# Quadrafire Castile Experiment



## tjnamtiw (Nov 28, 2010)

For quite a while, I have been thinking of ways to upgrade the caveman technology that Quad uses to transfer heat using the smooth aluminum tubes in their Castile and Sante Fe stoves.  The nice round, smooth tubes give the least amount of surface area for heat transfer both on the outside where they are exposed to the fire's heat and inside where they are supposed to transfer heat to the room air.  Why they aren't made of corrugated or finned material is beyond me based on the asking price for the stoves.  In any event, because of the mechanical wiper system, the outside didn't afford much opportunity for easy improvement.  I, therefore, focused on the inside of the tubes looking for ways to break up the assumed laminar flow of air that promotes lousy heat exchange and at the same time increase the surface area exposed to the air flow for more heat transfer.
As an experiment, I purchased from McMasterCarr some 36" long 1 1/4" diameter spring material (9662K46) and cut it into 9" lengths.  I then bent the one end so that I could grab it with pliers and push and rotate it clockwise into the 8 center tubes, leaving the first and last tube as is since little air flows through them.  Here is hopefully a picture.

Next I let the stove reach steady state at Medium with a flame height just barely out of the fire pot.  Then I measured the exhaust temperature just past the quick disconnect on the stove.  Finally, starting from the left, I measured the room temperature air coming out of each tube.  Then I inserted the springs in tubes #2-9 and waited 1/2 hour for stabilization and then measured everything again.  Here are my results:

Exhaust temp before = 170F   after = 160F
Tube 1 before = 150F  after = 135F
Tube 2 before = 145F  after = 152F
Tube 3 before = 140F  after = 161F
Tube 4 before = 142F  after = 162F
Tube 5 before = 160F  after =  158F
Tube 6 before = 160F  after = 172F
Tube 7 before = 141F  after = 150F
Tube 8 before = 140F  after = 150F
Tube 9 before = 160F  after = 165F
Tube 10 before = 200F  after = 165F

Conclusions >  The exhaust temperature appears to show that less heat is going up the chimney, which logically means more is going into the room.
Tube 1's lower temperature is a bit of a mystery since it is the first tube to see the fire's heat.  Very little airflow comes out of that tube so effect is minimal.
Tubes 2 through 9, except 5, show an increase in heat output due, I imagine, from the added surface area and the spiral effect of the air flowing through the tubes and breaking up the laminar flow.  Tube 5 was really a wash for increase.
Tube 10 has very, very little airflow through it so it had plenty of time to pick up heat before the exhaust exits the stove.  The fact that the temperature dropped dramatically could be and indication that the previous tubes have removed much more of the heat from the exhaust, leaving less to transfer to the tube #10.

Next, I will order enough springs to do my Sante Fe PLUS order a Dwyer Meter, which will supply one important bit of information, the air flow rate out of each tube.  This will answer the question as to if the springs severally limit the airflow, which would explain the higher temps.  However, the lowering of the exhaust temperature points toward a positive net gain in efficiency.

Sorry it's so long but some may find this interesting.  Others may be asleep by now.   %-P


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## Countryboymo (Nov 29, 2010)

That is a great idea but I would be afraid of cutting the airflow.  I am curious of the results.


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## tjnamtiw (Nov 29, 2010)

Without an airflow meter, I can't really tell but, to me, it's still blowing like gang busters and the air is definitely hotter than before.  The real telling piece of evidence is the exhaust temp going down.  Twice today I overshot my thermostat setting by an extra degree also, meaning it was putting out more heat faster before the thermostat could shut it down.  That never happened before.
No worries on cutting the airflow, IF THAT IS HAPPENING, because of the overheat snap disc, which hasn't tripped.  
It's definitely working.

Thanks for reading the thesis.  )


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## flynfrfun (Nov 29, 2010)

Very interesting.  Thanks for doing this experimentation.  Like you I have wondered why something that would be so simple for a manufacturer to design is not done?  I like how your spring idea is so easy to do for the rest of us if your final result is positive.
Flynfrfun


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## tjnamtiw (Nov 29, 2010)

flynfrfun said:
			
		

> Very interesting.  Thanks for doing this experimentation.  Like you I have wondered why something that would be so simple for a manufacturer to design is not done?  I like how your spring idea is so easy to do for the rest of us if your final result is positive.
> Flynfrfun



Thanks flynfrfun (full scale or RC planes????).  I wish I could figure a way to clamp some fins on the outside of the tubes and lose the scrapers.  I'm ordering spring material tomorrow for my Sante Fe and I will redo the experiment with it.  All in all, I think it's a positive step for very little money and completely reversible if questions of warranty arise.


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## Wi Thundercat (Nov 29, 2010)

Very interesting  :gulp:  Please keep us posted!  ;-)


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## Countryboymo (Nov 29, 2010)

I am curious what could be done inside the stove in conjunction to this.  The more I ponder the more I am intrigued.  Great job!


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## Nicholas440 (Nov 29, 2010)

I have a Castile insert,  and  I've always thought they used the cast aluminum for the fastest heat absorption like the aluminum discs used in good cookware.   I'm not sure what the idea is about the round tubes, I just assumed the engineers at Quadrafire researched this and came up with the round tube design.  The hot air flows over the tubes and gets them very hot.  Personally I think the idea of fins sounds  fine however,  have you seen how much ash gets on the topside of those tubes? This is I think why  those tubes are round. Any excess ash build up will not stick to the round sides of the tubes it drops off onto that stainless steel baffle plate just below it.    If you had fins in there  those fins would be clogged with ash in no time and they would be a real pain to clean. You want something in that hot air flow that will be quick to absorb a lot of heat  and not load up with fly ash the could eventually clog the air flow thus making the cleaning job a lot more work. 


I dont think putting springs or anything inside the tubes is going to improve their efficiency. What it will do is cut the air flow down in the tubes and you have less air coming out.  It might be hotter air because you have restricted it somewhat so its slower, and the air sits in the tubes a second or so longer therefore it is hotter.  The trick is to push a lot of air through a heat exchanger and into the room thats carrying with it the greatest amount of heat.  

My thinking long ago was they could have used a second heat exchanger , in other words pass the air over the main heat exchanger, then instead of having the hot air exit the stove right away  pass it over a smaller secondary exchanger just as it exits up the exhaust vent pipe.  A larger diameter vent pipe with hollow copper coil in it could capture some heat also and being hollow this tube could have air flowing through it back into the main exhanger or have its own vent into the room.  Anything to pull more heat out of the exhaust air and into the room would be a good thing.   You could have a  long copper tube inside the vent pipe that goes up about 5 feet which would capture a lot of escaping heat thats in the exhausting air. 

This is a good topic for discussion for sure.  I think many of us, with whatever brand stove we have has often thought about how to get more heat out of them.    It would be interesting to hear what ideas some of the others here in the forum might have to get more heat out of their stoves.


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## tjnamtiw (Nov 29, 2010)

Nicholas440 said:
			
		

> I have a Castile insert,  and  I've always thought they used the cast aluminum for the fastest heat absorption like the aluminum discs used in good cookware.   I'm not sure what the idea is about the round tubes, I just assumed the engineers at Quadrafire researched this and came up with the round tube design.  The hot air flows over the tubes and gets them very hot.  Personally I think the idea of fins sounds  fine however,  have you seen how much ash gets on the topside of those tubes? This is I think why  those tubes are round. Any excess ash build up will not stick to the round sides of the tubes it drops off onto that stainless steel baffle plate just below it.    If you had fins in there  those fins would be clogged with ash in no time and they would be a real pain to clean. You want something in that hot air flow that will be quick to absorb a lot of heat  and not load up with fly ash the could eventually clog the air flow thus making the cleaning job a lot more work.
> 
> 
> I dont think putting springs or anything inside the tubes is going to improve their efficiency. What it will do is cut the air flow down in the tubes and you have less air coming out.  It might be hotter air because you have restricted it somewhat so its slower, and the air sits in the tubes a second or so longer therefore it is hotter.  The trick is to push a lot of air through a heat exchanger and into the room thats carrying with it the greatest amount of heat.
> ...



Enjoyed your input.  Yes, the aluminum tubes (not sure they are cast though) are four times better conductors of heat than steel; however, copper would be almost twice as good as aluminum!  Also, you're also right about the fins on top of the tubes collecting ash.  If you put fins up there, an alternate means of cleaning would have to be available, such as access holes for a small brush or scraper.  

40 Years ago I had a heat extraction mechanism in my fireplace that doubled as andirons.  It was curved tubes that were open at the top and bottom and served to heat the air flowing through them.  That's the SAME technology used today on these stoves!  We now have the capability of extruding all shapes of aluminum that would present much more surface area on both the inner and out surfaces for better heat transfer.  One glaring problem with using smooth walled tubing is that you get laminar flow.  With laminar flow, you have a stagnant, slow-moving layer of air at the surface, which is not mixing with the central, faster-moving stream of air.  Heat transfer is poor.  Pushing even more air faster through the tubes, as you suggest, would only compound the problem.  What you need is some means of breaking up that stagnant layer and mixing it with the rest of the air.  You can use corrugations, a rough surface, fins or other irregularities to do that.  At the same time, these irregularities present a greater surface area to the air for more heat transfer.

I can't argue with the assumption that POSSIBLY I am restricting air flow by putting the springs in the tubes since I have no data to refute it.  That WOULD allow the air more time to pick up heat before exiting.  However, I am NOT reducing the inside diameter of the tube by the thickness of the spring since it is a spiral and still allows air to flow along the spiral and out the exhaust.  Certainly there is some restriction but, based on the fact that the exhaust temperature has gone down, the NET effect of heat transfer improvement is positive.  I have broken up the laminar flow.  Because the springs fit tightly against the tubing, I have also increased the surface area presented to the airflow significantly, thereby putting more heat into the air stream.  

I also agree with you that a second heat exchange mechanism would be great to extract more heat from the exhaust.  By my measurement, the exhaust is about 160F, so there is still some heat going up the stack.  One more pass over another set of tubes would have been possible to design.  Of course, if they would use more modern designs of heat exchangers such as in the AE, there would not be a need for this.  I wonder what the measured exhaust temperature of the AE is.......  Can someone measure that?????  Caution: infrared temperature measuring devices act differently on dark and shiny surfaces.  Check to see if you have a switch or setting for each type.  

Finally, even if you wanted to stay with smooth tubing, Quad could have used two or three times as many smaller diameter copper tubes in a staggered pattern, which would have reduced the room airflow resistance and at the same time, presented much more surface area of tubing having twice the heat transfer coefficient of aluminum.


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## tjnamtiw (Nov 29, 2010)

Countryboymo said:
			
		

> I am curious what could be done inside the stove in conjunction to this.  The more I ponder the more I am intrigued.  Great job!



me too!  Maybe we need a Quad Testing Lab, but I don't want to go to China!


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## Czech (Nov 29, 2010)

Excellent post TJ. I've own a Castile for around 6 years now, yes I've played with a bit because that is my nature. One question I've always had on this stove, why the baffle that covers the tubes and collects ash? The only big mod I've done is the door gasket, I like the cheap less than 10 dollar 3/4 stuff and not the $50+ tad pole! Keep us posted please.


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## tjnamtiw (Nov 29, 2010)

Czech said:
			
		

> Excellent post TJ. I've own a Castile for around 6 years now, yes I've played with a bit because that is my nature. One question I've always had on this stove, why the baffle that covers the tubes and collects ash? The only big mod I've done is the door gasket, I like the cheap less than 10 dollar 3/4 stuff and not the $50+ tad pole! Keep us posted please.



Thanks!  I've tried to make sense out of that baffle too   :ahhh:   There's some really half-arsed technology in the whole heat transfer system IMHO.  

Like the 'Czech' sig.  Mine should be 'Slovak'..  Jasenov, Slovakia > grandpop's home


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## flynfrfun (Nov 29, 2010)

tjnamtiw said:
			
		

> flynfrfun said:
> 
> 
> 
> ...



I fly small RC electric planes & helis from my driveway and a paramotor from local farmer's fields.  Lots of fun!  I like your idea of the spring (if it works out) because it is an easy retrofit to existing pellet stoves.  I know we can all come up with different designed heat exchangers that would be more efficient, but unless you want to cut apart your stove and re-weld it all back together, very few people will be willing to do that.  I would think that a corrugated or star shaped tubing could have just as easily been used on a lot of these stove heat exchangers and been a lot more efficient.  It would still be easy to have a scraper with a star shape instead of a circle.  I think it's about time pellet stove manufacturers put a lot more thought into the heat exchanger.  I know Quad did the airfoil exchange on the Mt Vernon and I think Harman has a fluted type of setup.  The airfoil is neat, but I haven't heard any discussions about how it compares side by side to plain round tube exhanger stoves.  In other words, how much air flow at a certain temp with a measured rate of pellet usage for both stoves.  I see manufacturers efficiency ratings, but have to wonder how they come up with them.  For instance my Enviro M55 cast insert was advertised a week ago with 76.5% efficiency (round tube heat exchanger).  I noticed this week they have updated their website and now they claim 83.5% efficiency.  That's a big difference.  I emailed them to find out just what changed?  No response yet.  Do these mfg just grab a number out of thin air similar to the other stove's specs to keep their stoves selling?
Flynfrfun


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## Czech (Nov 29, 2010)

The name follows me from forum to forum on the 'net, thanks. Rather than springs, how about flat alum stock cut to fit the diameter? Say 1 foot (whatever the top tube length is) by 1 1/2" (whatever diameter tube are) by 1/8 thick? I know it would take some shop time, but what else do we have to do all winter except fill the stove and blow snow? And let's get some measurements without that darn baffle all other varibles controlled.


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## skidozer (Nov 29, 2010)

I work for a large company that makes heat exchangers for power industry.

Sometimes we use twisted strips inside of the tubes like czec mentioned above then you gain surface area.
Its always a balance of heat transfer and pressure drop.


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## tjnamtiw (Nov 29, 2010)

skidozer said:
			
		

> I work for a large company that makes heat exchangers for power industry.
> 
> Sometimes we use twisted strips inside of the tubes like czec mentioned above then you gain surface area.
> Its always a balance of heat transfer and pressure drop.



That's interesting!  Twisting the 'Czech' strips would spiral the airflow and break up the laminar effect!  hmmmmmmmmmmmmmmm.  We might actually come up with something effective for all the tube exchangers.  The Quad tubes are 1.25" ID.  I almost got thrown because I measured them with a mike but didn't go in far enough and measures 1.32".  Here they have a little flare at the end for some reason.  

Too bad there isn't a Quad factory rep on here to tell us what that baffle is for.  Maybe just to slow down the exhaust speed?  It almost looks like it's BLOCKING the flow!


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## tjnamtiw (Nov 29, 2010)

flynfrfun said:
			
		

> I fly small RC electric planes & helis from my driveway and a paramotor from local farmer's fields.
> Flynfrfun



I fly RC too.  1/3 scale 9' wingspan Sopwith Pup, .60 size YouCanDo, .40 size Kaos, .60 size Stuka.  etc etc.  Boy's toys.............


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## B-Mod (Nov 29, 2010)

I think the plate is there to slow down the exhaust. I know a few have tried removing the plate on a Bixby, and all the heat went straight out the exhaust.........


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## slls (Nov 29, 2010)

And to keep from warping the tubes, even though some have warped the tubes with baffle plates installed.


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## tjnamtiw (Nov 29, 2010)

slls said:
			
		

> And to keep from warping the tubes, even though some have warped the tubes with baffle plates installed.



So people have removed the little plate that is welded to the upper stainless steel plate that covers to tubes?  Just want to make sure we are talking about the same thing.

I ordered two of those adjustable snap discs, Bmod.   Just timed my Castile.  It took 7 minutes to start the blower after establishing a flame.


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## Czech (Nov 29, 2010)

I'm talking the baffle that is removable, slot hooks on the edges and covers the tubes on the top inside of the firebox, side forward and down to remove. Reasons above make sense I guess.


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## SmokeyTheBear (Nov 30, 2010)

That's a nice easily reversible little experiment you are running TJ.

Most of the baffles I've seen are used to direct the exhaust gases so they don't exit the stove before they have somewhat of a chance to heat the heat exchanger instead of making a beeline for the vent.


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## tjnamtiw (Nov 30, 2010)

SmokeyTheBear said:
			
		

> That's a nice easily reversible little experiment you are running TJ.
> 
> Most of the baffles I've seen are used to direct the exhaust gases so they don't exit the stove before they have somewhat of a chance to heat the heat exchanger instead of making a beeline for the vent.



Thanks, Smokey, I appreciate the compliment!


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## Wachusett (Nov 30, 2010)

I do agree, is there a better way to extract/transfer heat out of the stove.
However is this really increasing the heat gained. The total net. difference in temperature output
only appears to be about 3 degrees. (before avg. temp =153.8 after avg. temp=157). I would think the
springs also would cause more friction vs. a smooth tube = less velocity and fan working harder.

Just my 2 pennies, interesting idea though.


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## SmokeyTheBear (Nov 30, 2010)

It is quite possible that the convection fan hardly knows those springs are there.

How big is the fan outlet on the convection fan?   Before the reduction the fan was seeing a 12.27 square inch outlet at the stove front.


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## smalltown (Nov 30, 2010)

Nice testing and some interesting ideas. I especially like the idea that these changes are reversible. I wonder if the baffle plate was cast iron wouldn't it heat up and radiate more heat toward the tubes?


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## B-Mod (Nov 30, 2010)

How many heat tubes does everyone have??? My stove is one of the first ones, Oct 2001, if I remember right. I only have 8 tubes, every picture I can find and parts books show 10. My owners manual shows 8..........Brian


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## smalltown (Nov 30, 2010)

Mine has 10 tubes the #1 and #10 are partially blocked by the decorative casting.


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## tjnamtiw (Nov 30, 2010)

Wachusett said:
			
		

> I do agree, is there a better way to extract/transfer heat out of the stove.
> However is this really increasing the heat gained. The total net. difference in temperature output
> only appears to be about 3 degrees. (before avg. temp =153.8 after avg. temp=157). I would think the
> springs also would cause more friction vs. a smooth tube = less velocity and fan working harder.
> ...



Sorry, but that's a bad assumption to just average the temperature gains and losses because you don't take into account the flow rates through each tube which equates to btu's coming out of each tube.  Unfortunately I haven't been able to spring for the cost of a flow meter to put this to rest.  You are adding the tubes 1 and 10 into the equation and they have almost no flow at all.  Throw them out and see what you get.  Also, you're missing the point of less heat going up the flue..  Where is it going???  Out into the room.  Rather than readdress the basic premise of the test, I'll let you read what I wrote again.  I'm just looking for a way to break up the flow and get some turbulent flow to better extract the heat and at the same time present more surface area to the flow.


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## tjnamtiw (Nov 30, 2010)

SmokeyTheBear said:
			
		

> It is quite possible that the convection fan hardly knows those springs are there.
> 
> How big is the fan outlet on the convection fan?   Before the reduction the fan was seeing a 12.27 square inch outlet at the stove front.



Right on Smokey.  It's actually two squirrel cage fans.  Don't know the fan outlet size.  One other thing is that the tubes are in parallel, which, like an electrical circuit, reduces the resistance to flow of air.  That's why I wished that they had put three times more COPPER tubes in there even if they were smaller.  I think that's what they did to the Bixby, but not sure.

After the springs, I'm not sure how you would compute the outlet area because they really aren't blocking the air as much as they are rerouting it into a spiral flow.  you would need some very sensitive pressure gauges at both ends to see the difference.   I still like the alternate idea of a spiral piece of flat stock fitted snugly down the tube to cause the flow to divert plus give more surface area.


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## tjnamtiw (Nov 30, 2010)

smalltown said:
			
		

> Nice testing and some interesting ideas. I especially like the idea that these changes are reversible. I wonder if the baffle plate was cast iron wouldn't it heat up and radiate more heat toward the tubes?



also a good idea.  As a 'doable' alternate, you could weld some fins on the bottom side to increase surface area and pick up more heat.  Maybe AFTER the warranty runs out.   %-P


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## Countryboymo (Nov 30, 2010)

We need a honeycomb like material that would slide down the tubes that wouldn't restrict airflow much but would have a lot more surface area.  It could be slid out and rinsed down or washed in the dishwasher every ton of pellets or so.  Wow I can picture it in my head and its made out of that space age material that is super thin but a super conductor of heat.... unobtanium.  I apologize, I started daydreaming and woke up at the point of my skin melting from walking in front of the 'pellet reactor'.


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## Wi Thundercat (Nov 30, 2010)

My st.croix has 16 tubes that are approx 3/4"-7/8" in diameter. Seems to me that they used the spiral flat inside the flues on some of the oil burners we cleaned. Imagine this was to improve heat transfer!


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## tjnamtiw (Nov 30, 2010)

Countryboymo said:
			
		

> We need a honeycomb like material that would slide down the tubes that wouldn't restrict airflow much but would have a lot more surface area.  It could be slid out and rinsed down or washed in the dishwasher every ton of pellets or so.  Wow I can picture it in my head and its made out of that space age material that is super thin but a super conductor of heat.... unobtanium.  I apologize, I started daydreaming and woke up at the point of my skin melting from walking in front of the 'pellet reactor'.



Actually, that is not so far-fetched an idea!  There are also things called 'heat pipes' that move heat from one place to another through a tube without any moving parts.  They could be used to bring heat back from the exhaust and into a secondary blower system.  All sorts of things are possible.


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## tjnamtiw (Nov 30, 2010)

Wi Thundercat said:
			
		

> My st.croix has 16 tubes that are approx 3/4"-7/8" in diameter. Seems to me that they used the spiral flat inside the flues on some of the oil burners we cleaned. Imagine this was to improve heat transfer!



With the 16 tubes, you are probably ahead of the game.  There's another example of the spiral flats!  Someone knows what they are doing!


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## Czech (Nov 30, 2010)

Venturi Effect? Mine has 10 tubes, two partially blocked as mentioned.


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## tjnamtiw (Nov 30, 2010)

Czech said:
			
		

> Venturi Effect? Mine has 10 tubes, two partially blocked as mentioned.



Didn't think about that, but it would help, I guess.  Why would they incorporate that and not use any of the other things people have brought up??  Crazy Chinamen!


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## tjnamtiw (Dec 1, 2010)

Well, I cut the springs for my Sante FE, took initial readings, inserted the springs, waited for the same fire volume and took second readings.  The readings are very similar to those I measured on the Castile, which probably is not surprising since their guts are basically the same.  Both stoves were given the monthly cleaning prior to readings being taken.

Tube 1 before 170 after 160
Tube 2 before 165 after 182
Tube 3 before 140 after 170
Tube 4 before 140 after 160
Tube 5 before 170 after 175
Tube 6 before 190 after 200
Tube 7 before 145 after 155
Tube 8 before 140 after 155
Tube 9 before 180 after 180
Tube 10 before 190 after 165

Exhaust temp before 170 after 160

As with the Castile, the lowering of exhaust temp shows that less heat was going up the chimney and therefore going into the room.  Very little airflow comes out of the first and tenth tubes so those readings are moot IMO and no springs were installed.  For tube 10, I can only assume that less heat is available to transfer there since more has been extracted with the previous tubes.


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## slls (Dec 1, 2010)

Would not a larger stove be more practical than trying to get more heat out of a smaller stove.
My CB1200 gives all the heat I need on medium setting.


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## tjnamtiw (Dec 1, 2010)

slls said:
			
		

> Would not a larger stove be more practical than trying to get more heat out of a smaller stove.
> My CB1200 gives all the heat I need on medium setting.



Hindsight is a wonderful thing.  After dropping over $6K for two stoves plus installation, it's really not in the equation.  If you're happy blowing 170 degree air out the exhaust, then there's not a problem.  When you talk to Bixby owners and they tell you they can lay their hand on a barely warm exhaust pipe outside, you know that you have something less than efficient.

Because of my floor plan, one stove would not have heated my family room at all, so I needed a second stove anyway.  If you buy these things, you have to either be a tinkerer or insane.  I like to think I'm the first but don't ask my wife.


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## Trail_Time (Dec 3, 2010)

I am interested to see further discussion on this.  Thanks for taking the time to post.

Have you tried removing the springs from tube 1 and 10 and see what happens to the temps on those tubes?


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## slls (Dec 3, 2010)

tjnamtiw said:
			
		

> slls said:
> 
> 
> 
> ...



Well I run mine on medium heat and high fan, I can hold my hand on the vent pipe 6 inches from the stove adapter and leave it there all day.
My oil furnace vents at 500 deg F, nothing I can do about that either.


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## YooperD2 (Dec 3, 2010)

tjnamtiw said:
			
		

> Well, I cut the springs for my Sante FE, took initial readings, inserted the springs, waited for the same fire volume and took second readings.  The readings are very similar to those I measured on the Castile, which probably is not surprising since their guts are basically the same.  Both stoves were given the monthly cleaning prior to readings being taken.
> 
> Tube 1 before 170 after 160
> Tube 2 before 165 after 182
> ...



That makes me want to go to the spring store to modify my Santa Fe. Thanks for posting your test.


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## tjnamtiw (Dec 3, 2010)

Trail_Time said:
			
		

> I am interested to see further discussion on this.  Thanks for taking the time to post.
> 
> Have you tried removing the springs from tube 1 and 10 and see what happens to the temps on those tubes?



Actually, I don't have springs in tubes 1 and 10 because the springs I bought were 36" long each and I cut them into 9" lengths so I ended up with 8 springs from the 2 initial 4' springs.  I figured that with the small amount of air coming out of the outer tubes, it would not be worth the effort to buy and insert springs in them.  In hindsight, I could have bought an extra spring when I bought my second set of springs for my second stove but I didn't think of it.   :red:


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## tjnamtiw (Dec 3, 2010)

[quote author="slls" date="1291415542
Well I run mine on medium heat and high fan, I can hold my hand on the vent pipe 6 inches from the stove adapter and leave it there all day.
My oil furnace vents at 500 deg F, nothing I can do about that either.[/quote]

Wow, you're either 'tougher' than I am or the Classic Bay had upgraded their design for better heat extraction because I can't keep my hand on 170 degrees.  Now I'm measuring on an insert right after the stove's detachable outlet.

How do you get the high fan on medium heat?  We don't have those choices on Sant Fe's and Castile's unless you rewire it like b-mod did.  

Oh, I forgot to mention that the Classic Bay would not fit in the width of my little fireplace.  If I remember it was like 1/2" too wide.  My Sante Fe JUST fits!!


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## tjnamtiw (Dec 3, 2010)

[quote author="nuYooper" date="1291416680

That makes me want to go to the spring store to modify my Santa Fe. Thanks for posting your test.[/quote]

You're welcome.  Yes, give it a try.  I got my bill from McMasterCarr and it was $18 including shipping.


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## thz123 (Dec 3, 2010)

Keep me posted too. I have the Castile too. I like this idea, and might try it. I have wondered why there arn't blower motors for the side walls. I have tried to move air through these side walls, and haven't figured out quit how to do it correct. If I put a small fan blowing under the stove I do get some heat out of the side "vents". Instead of the springs would flat aluminum or copper metal work like someone suggested above? Or I wonder if steel wool in the tube somehow would work too? It would have to be easily removed too, and I don't know how to do that. Great idea!


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## slls (Dec 3, 2010)

tjnamtiw said:
			
		

> [quote author="slls" date="1291415542
> Well I run mine on medium heat and high fan, I can hold my hand on the vent pipe 6 inches from the stove adapter and leave it there all day.
> My oil furnace vents at 500 deg F, nothing I can do about that either.



Wow, you're either 'tougher' than I am or the Classic Bay had upgraded their design for better heat extraction because I can't keep my hand on 170 degrees.  Now I'm measuring on an insert right after the stove's detachable outlet.

How do you get the high fan on medium heat?  We don't have those choices on Sant Fe's and Castile's unless you rewire it like b-mod did.  

Oh, I forgot to mention that the Classic Bay would not fit in the width of my little fireplace.  If I remember it was like 1/2" too wide.  My Sante Fe JUST fits!![/quote]

Yes different stove, 3 heat settings, low ,med, hi, fan settings, low, hi. the fan speed is different for the 3 heat settings, each higher for each mode.

I work with my hands a lot, maybe that's why I can take the heat.


----------



## tjnamtiw (Dec 4, 2010)

slls said:
			
		

> Yes different stove, 3 heat settings, low ,med, hi, fan settings, low, hi. the fan speed is different for the 3 heat settings, each higher for each mode.
> 
> I work with my hands a lot, maybe that's why I can take the heat.



So you have a high and low setting for each of the three heat settings?  Damn, I wish mine had that!  The low fan on low heat is about useless.

Like the comment on the 'take the heat'.   Hey, I'm married so I CAN TAKE THE HEAT TOO  ha ha ha.  I have a feeling with the high fan setting on the lower heat levels you are getting better heat transfer.


----------



## tjnamtiw (Dec 4, 2010)

thz123 said:
			
		

> Keep me posted too. I have the Castile too. I like this idea, and might try it. I have wondered why there arn't blower motors for the side walls. I have tried to move air through these side walls, and haven't figured out quit how to do it correct. If I put a small fan blowing under the stove I do get some heat out of the side "vents". Instead of the springs would flat aluminum or copper metal work like someone suggested above? Or I wonder if steel wool in the tube somehow would work too? It would have to be easily removed too, and I don't know how to do that. Great idea!



I like your thinking on a fan to extract heat from the sidewalls.  This would help with an insert since that heat is going into the chimney area instead of the room but it wouldn't make any difference with a free standing one, I don't think.

I wouldn't think the steel wool would work because it would REALLY restrict airflow and maybe even trip your overheat snap switch.  I really DO like the idea that was brought up earlier about a 1 1/4" wide piece of flat stock twisted in a spiral and inserted into the tubes.  It would be less restrictive and give about 2/3 more surface area.  It is certainly worth a try.  Original surface area is pi X 1 1/4".  The flat stock would have two surfaces each 1 1/4" long.  Pi is 3.14 so we end up with 5.14 diameters of surface area.


----------



## YooperD2 (Dec 4, 2010)

The spring stock is on the way for the Santa Fe. At such a small up front cost, less than 4 bags of pellets, any long run gain is worth it to me.


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## tjnamtiw (Dec 4, 2010)

nuYooper said:
			
		

> The spring stock is on the way for the Santa Fe. At such a small up front cost, less than 4 bags of pellets, any long run gain is worth it to me.



Good for you.  Let us know what you think!


----------



## Wi Thundercat (Dec 4, 2010)

Now this is getting interesting !!    Stay tuned! :bug:


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## tjnamtiw (Dec 4, 2010)

Wi Thundercat said:
			
		

> Now this is getting interesting !!    Stay tuned! :bug:



We're waiting for you to get some flat stock to put in those 16 tubes!  Join the party!


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## Wi Thundercat (Dec 4, 2010)

tjnamtiw said:
			
		

> Wi Thundercat said:
> 
> 
> 
> ...



Believe me i have been thinking of what material to use! Copper, stainless,........Will have to pull cover off tubes and mic them and see what i can find!


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## tjnamtiw (Dec 4, 2010)

yea, I just was on McMaster Carr and the copper is EXPENSIVE!  So is the aluminum.  More than I thought.  That's disappointing but it still might be worth it with that much increase in surface area.  Maybe buy some at a scrap yard and find a friendly machinist to mill it down to the right width........  Try just a few tubes to see results.


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## Countryboymo (Dec 4, 2010)

I think even one small piece of thin flat stock in a slow spiral would make a huge difference.   I am thinking of what material to use and how or where to get the nice even swooping twist.


----------



## Wi Thundercat (Dec 4, 2010)

Cousin owns a scrap yard and is quite the machinist too! We have built and tried some crazy s#*t over the years ! Most with great results but some were a bust


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## tjnamtiw (Dec 4, 2010)

Countryboymo said:
			
		

> I think even one small piece of thin flat stock in a slow spiral would make a huge difference.   I am thinking of what material to use and how or where to get the nice even swooping twist.



I think you are right.  I know I've seen that same thing employed in furnaces as someone else commented.  Anchor one end in a vise and twist the other end with vise grips or even a slow speed drill (if it's thin metal like 20 gauge or so).


----------



## tjnamtiw (Dec 4, 2010)

Wi Thundercat said:
			
		

> Cousin owns a scrap yard and is quite the machinist too! We have built and tried some crazy s#*t over the years ! Most with great results but some were a bust



It sounds like you are in the driver's seat!


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## jtakeman (Dec 4, 2010)

Interesting thread. I wonder if it will work or have an effect on other round convection tubed stoves? Like the Breckwell bigE for instance. 

Lowering the exhaust temps without playing with combustion air has to be a plus to the stoves overall efficiency.


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## thz123 (Dec 4, 2010)

Last night I cut up some different shaped aluminum to 9", and inserted them except the outside 2. I had flat pieces of different thicknesses and widths. Two pieces were shaped like this  [ . Those 2 pieces were smaller than the I.D. This was all scrap material. I tried each piece in different configurations inside the tubes. I feel they restricted air flow. I took them all out. At 9" the flat stuff may be too long causing a restriction all the way in the back of the tube were the air comes up from the fan. I did pull a few further to the front of the tube, but they still felt restricted to me. I did drill holes in the ends of them, thinking that I could shorten them and use a piece of wire so that I can pull them out. I haven't cut them down yet, waiting to see what others try. They were good and hot when removed. I plan to watch this thread to see what the outcome is.


----------



## slls (Dec 4, 2010)

tjnamtiw said:
			
		

> slls said:
> 
> 
> 
> ...



Very good heat transfer on high, another bonus is the fan is low, so it acts like a cold air return. 
It took me a while to figure out why the mud room, 2 doors away, was warm like the other rooms.


----------



## B-Mod (Dec 4, 2010)

Not sure If I posted it in here or not.....but I am heating my whole house 1600 sq ft with stove on low heat, convection fan on high, springs (thanks tjnamtiw!) in tubes 2 thru 7 (my stove only has 8 tubes, early model). 71 degrees in the house, 20 degrees outside air temp, and snowing. I am burning straight corn, top airwash sealed off, bottom gasket removed. 9 Years and this stove has burnt nothing but corn. I only tried pellets once or twice when it was warm in the spring to use the room thermometer.............


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## tjnamtiw (Dec 4, 2010)

j-takeman said:
			
		

> I
> Lowering the exhaust temps without playing with combustion air has to be a plus to the stoves overall efficiency.



Yep, that's what I have been assuming.  If it isn't going up the stack, it's going into the room.


----------



## tjnamtiw (Dec 4, 2010)

thz123 said:
			
		

> Last night I cut up some different shaped aluminum to 9", and inserted them except the outside 2. I had flat pieces of different thicknesses and widths. Two pieces were shaped like this  [ . Those 2 pieces were smaller than the I.D. This was all scrap material. I tried each piece in different configurations inside the tubes. I feel they restricted air flow. I took them all out. At 9" the flat stuff may be too long causing a restriction all the way in the back of the tube were the air comes up from the fan. I did pull a few further to the front of the tube, but they still felt restricted to me. I did drill holes in the ends of them, thinking that I could shorten them and use a piece of wire so that I can pull them out. I haven't cut them down yet, waiting to see what others try. They were good and hot when removed. I plan to watch this thread to see what the outcome is.



It sounds like you were on the right track.  I could see if they were all the way in back and horizontal that they might cut the airflow.  But if they were further forward, I can't see how they would do much restricting.  I still haven't gotten my EBay airflow meter 'bargain'.  (   Don't give up yet.


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## tjnamtiw (Dec 4, 2010)

B-Mod said:
			
		

> Not sure If I posted it in here or not.....but I am heating my whole house 1600 sq ft with stove on low heat, convection fan on high, springs (thanks tjnamtiw!) in tubes 2 thru 7 (my stove only has 8 tubes, early model). 71 degrees in the house, 20 degrees outside air temp, and snowing. I am burning straight corn, top airwash sealed off, bottom gasket removed. 9 Years and this stove has burnt nothing but corn. I only tried pellets once or twice when it was warm in the spring to use the room thermometer.............



That's amazing, b-mod!  Who said tinkering doesn't pay?


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## thz123 (Dec 4, 2010)

I am about to order the springs, How did you cut them to 9"?


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## tjnamtiw (Dec 4, 2010)

thz123 said:
			
		

> I am about to order the springs, How did you cut them to 9"?



I put the spring in a vise and used a side grinder to cut through.  You could also use a Dremel tool with the cutoff wheel.  Use the wheels with the reinforcement in them.  They also sell a wheel that is just a thin disc and they have a habit of exploding into nasty pieces of shrapnel.  Don't know how they can sell them.


----------



## SmokeyTheBear (Dec 4, 2010)

tjnamtiw said:
			
		

> j-takeman said:
> 
> 
> 
> ...



You have to watch out for condensing crap out of the exhaust, where are you measuring the exhaust temps at?


----------



## thz123 (Dec 4, 2010)

I just ordered 2 sets of springs, they ship out Monday.


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## tjnamtiw (Dec 4, 2010)

SmokeyTheBear said:
			
		

> tjnamtiw said:
> 
> 
> 
> ...



hi Smokey.  I measured the surface temp of the exhaust pipe just above where it is attached to the stove's two part exhaust stack.  I used that as a reference point for all my tests and measurements.


----------



## tjnamtiw (Dec 4, 2010)

thz123 said:
			
		

> I just ordered 2 sets of springs, they ship out Monday.



Good for you.  Keep us up to date on your testing, please.


----------



## SmokeyTheBear (Dec 4, 2010)

tjnamtiw said:
			
		

> SmokeyTheBear said:
> 
> 
> 
> ...



Just thought you should know that as the exhaust gets colder things will condense out in the exhaust that you are likely not going to want to see there.

So just keep an eye on it while playing.


----------



## tjnamtiw (Dec 5, 2010)

SmokeyTheBear said:
			
		

> tjnamtiw said:
> 
> 
> 
> ...



Yea, you're right but I have 17' of flex going up my chimneys so I imagine I'll have plenty of condensation.  Luckily (I guess) I'm not burning corn like b-mod is so I won't have the acid to contend with.  Thanks for your comments and suggestions.  Always a pleasure.


----------



## B-Mod (Dec 5, 2010)

I only have 3' of pipe, no condensation here.........


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## tjnamtiw (Dec 5, 2010)

B-Mod said:
			
		

> I only have 3' of pipe, no condensation here.........



3" pipe here also. (oops, I thought I saw 3" and not 3')  

 Hey, I meant to ask you if you run a B modified dirt car, hence the 'handle'...


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## B-Mod (Dec 5, 2010)

No, only 3 feet of exhaust pipe here, not much chance for it condensing in that short of a distance.

No dirt car. Long last name, so kinda initials of first and last name. I have drag raced, and vintage snowmobile raced for years.


----------



## tjnamtiw (Dec 5, 2010)

Countryboymo said:
			
		

> We need a honeycomb like material that would slide down the tubes that wouldn't restrict airflow much but would have a lot more surface area.  It could be slid out and rinsed down or washed in the dishwasher every ton of pellets or so.  Wow I can picture it in my head and its made out of that space age material that is super thin but a super conductor of heat.... unobtanium.  I apologize, I started daydreaming and woke up at the point of my skin melting from walking in front of the 'pellet reactor'.



http://www.fuelefficiencyllc.com/fehxturb.html
This company makes turbulators and other products that fall into the realm of your ideas, which are very practical.  Probably more practical than my springs!


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## slls (Dec 5, 2010)

Shutting down the air wash will increase convection and radiation heat.


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## B-Mod (Dec 5, 2010)

slls said:
			
		

> Shutting down the air wash will increase convection and radiation heat.



Been working on this for a week or so now. It works good. I had top air wash door. I removed the seal from the bottom, and installed a new one at the top. Door glass is dirtier, but heat went up greatly in the low heat setting.


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## YooperD2 (Dec 7, 2010)

IT'S LIKE CHRISTMAS  The UPS tracking  said "out for delivery".  My springs are on the way maybe? I measured the pre-install temp. on the exhaust @ 190*. I'll post later what I find after I install the springs.  UPS guy just pulled in.....
ll post what I find later.


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## B-Mod (Dec 8, 2010)

Where I take my air temps it is normally 125 to 135 degrees on low, tonight I turned it up on high just to see and had temps around 210 degrees. She was hot..............


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## skidozer (Dec 8, 2010)

I had some scrap 1" stainless turbulators and I threw them out before I got the stove.

We used to chuck one end of the metal in a big lathe and hook the other end to the drill chuck and keep it loose so it could travel down the bed. Its been a long time since we made that product.

Going to see If I can make some to try sometime.


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## thz123 (Dec 8, 2010)

My springs arrived yesterday, and I plan to cut them up today. Insert them tonight. I do not have a way to measure the air temp. though.


----------



## tjnamtiw (Dec 8, 2010)

skidozer said:
			
		

> I had some scrap 1" stainless turbulators and I threw them out before I got the stove.
> 
> We used to chuck one end of the metal in a big lathe and hook the other end to the drill chuck and keep it loose so it could travel down the bed. Its been a long time since we made that product.
> 
> Going to see If I can make some to try sometime.



Yea, that's a great way to make the twist!  I could shear some galvanized I have laying around and use my wood lathe but I would have to hand turn it!  I can't go that slow.  worth a try, though.


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## tjnamtiw (Dec 8, 2010)

thz123 said:
			
		

> My springs arrived yesterday, and I plan to cut them up today. Insert them tonight. I do not have a way to measure the air temp. though.



In a pinch, a meat thermometer will do if you can keep it off of the wall of the tube.


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## YooperD2 (Dec 8, 2010)

I installed the springs today and found a 11* drop in exhaust temp. I don't have a proper way to measure the heat or air flow from the exchanger tubes. All seems well though. I should mention to people that are sensitive to odors to clean the springs before installing them as they will give off a little smell as the "new" burms off.


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## tjnamtiw (Dec 8, 2010)

nuYooper said:
			
		

> I installed the springs today and found a 11* drop in exhaust temp. I don't have a proper way to measure the heat or air flow from the exchanger tubes. All seems well though. I should mention to people that are sensitive to odors to clean the springs before installing them as they will give off a little smell as the "new" burms off.



That's GREAT!  I didn't have the problem with the oil burning off the springs.  My wife would have DEFINITELY brought it to my attention

well, it's good to hear that it's working though.  I just got my Dwyer wind speed meter but it is so darn cold here in Ga. (20 at night and 32 for a high today) that I haven't had a chance to screw with wind speeds with and without.  I would expect to see higher speeds with the springs installed IF I am restricting the flow.  However, the telling thing will be to find the relationship of speeds versus effective diameter to determine how many btu's are coming out of each tube.  That will take some serious thermodynamic computing.  Not sure I'm up to that after 45 years out of college.   %-P


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## thz123 (Dec 8, 2010)

I have the free standing Castile. I cut my springs to 9 inches. I tried to put them in tonight. I can't get them in. There is a heat deflector above my tubes. I can't get them in because of the angle due to the heat deflector. Its not a straight shot in. How did you get them in there? I am bummed, I was excited to try this....help me


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## B-Mod (Dec 8, 2010)

Turn and push them in at the same time. Kinda like screwing them in. My stove is older than yours but it should fit......


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## YooperD2 (Dec 9, 2010)

tjnamtiw:  I'll take your cold weather, as it will be close to 0*F here tonite. The shoulder season is just about over. I'll be looking forward to your future tests.


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## tjnamtiw (Dec 9, 2010)

nuYooper said:
			
		

> tjnamtiw:  I'll take your cold weather, as it will be close to 0*F here tonite. The shoulder season is just about over. I'll be looking forward to your future tests.



My 'shoulder season' used to be 50-60....   :cheese:   I lived through 9 years in Chicago with -30 one weekend.   Nooooo Thanks.............  

I am really interested in the idea of the turbulators.  Gotta try some and compare to the springs.


----------



## tjnamtiw (Dec 9, 2010)

thz123 said:
			
		

> I have the free standing Castile. I cut my springs to 9 inches. I tried to put them in tonight. I can't get them in. There is a heat deflector above my tubes. I can't get them in because of the angle due to the heat deflector. Its not a straight shot in. How did you get them in there? I am bummed, I was excited to try this....help me



Like B-mod said, turn and 'screw' them in.  That's why I bent the beginning of the spring in.  You can put pliers on them and turn CLOCKWISE.  My Castile doesn't have a deflector close enough to interfere BUT my Sante Fe DOES.  On that one, I had to bend the spring in an arc and turn it to get them in.  Also, of course, on the Sante Fe I had to take off the grill to get them in.  You can do it.  I have faith in you.


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## thz123 (Dec 9, 2010)

I was not able to bend the ends of the springs either, could that be the problem? could the ends be digging into the tube? I cut them with a bolt cutters at work. I tried the dremal but it was taking too long. I tried to put it in the 5th tube from the left and I pushed and turned at the same time. I tried two springs and they both stuck. How did you bend the ends over? How tight are they in the tubes? Thanks for the help. Tom


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## tjnamtiw (Dec 9, 2010)

thz123 said:
			
		

> I was not able to bend the ends of the springs either, could that be the problem? could the ends be digging into the tube? I cut them with a bolt cutters at work. I tried the dremal but it was taking too long. I tried to put it in the 5th tube from the left and I pushed and turned at the same time. I tried two springs and they both stuck. How did you bend the ends over? How tight are they in the tubes? Thanks for the help. Tom



Not bending in the ends is most likely your problem.  The bolt cutters probably put a nice burr on the ends.  I used channel lock pliers across the last loop of the spring and bent the free end in just a little on one end and then, if you look at my picture, I bent the other free end in almost to the center.  I also had to go and 'adjust' the first loop so that it wasn't sticking out of alignment.  The ends are dragging so if you fix that, you will see that the springs will go in quite easily with a twisting motion.  In fact, I have found after taking them in and out during measuring that they go in VERY easy when the tubes are hot.

If you have problems understanding what I was trying to convey, just ask!  We're here to help!

Tom


----------



## B-Mod (Dec 9, 2010)

I heated the ends of the spring with a map gas torch, bent like a wet (hot) noodle, lol..............


----------



## tjnamtiw (Dec 9, 2010)

B-Mod said:
			
		

> I heated the ends of the spring with a map gas torch, bent like a wet (hot) noodle, lol..............



that will definitely work, too!  It actually bends pretty easily with big pliers.  "If it won't fit, get a bigger hammer''


----------



## B-Mod (Dec 9, 2010)

I like playing with fire, lol..............


----------



## thz123 (Dec 9, 2010)

I used a torch to bend mine, they bent like butter, very easy. Then I "aligned" the spring ends using a vise. I will try to put them in tonight. When I tried to insert them yesterday the tubes were good and hot. Last night I shined a flashlight into the tube and I could see where the ends of the springs were digging into the tube. It doesn't take long for the spring to get hot, since I had to get a pair of leather gloves on in order to pull the spring back out. It was hot after only a few minutes. I hope they go in easy now.


----------



## thz123 (Dec 9, 2010)

I used a torch to bend mine, they bent like butter, very easy. Then I "aligned" the spring ends using a vise. I will try to put them in tonight. When I tried to insert them yesterday the tubes were good and hot. Last night I shined a flashlight into the tube and I could see where the ends of the springs were digging into the tube. It doesn't take long for the spring to get hot, since I had to get a pair of leather gloves on in order to pull the spring back out. It was hot after only a few minutes. I hope they go in easy now.


----------



## jackiec (Dec 9, 2010)

I ordered 3, 36" springs today for Santa Fe insert.  Am I correct in leaving tubes 1 and 10 empty? It looks like the best way to insert them is by taking the grill bars off in the front. Anyone try that?  Santa Fe does a nice job but if I had to it over again, I would treat the purchase like I was buying a TV.....Get the biggest one possible that fits.....


----------



## tjnamtiw (Dec 9, 2010)

jackiec said:
			
		

> I ordered 3, 36" springs today for Santa Fe insert.  Am I correct in leaving tubes 1 and 10 empty? It looks like the best way to insert them is by taking the grill bars off in the front. Anyone try that?  Santa Fe does a nice job but if I had to it over again, I would treat the purchase like I was buying a TV.....Get the biggest one possible that fits.....



Yea, I did my Sante Fe too.  You have to take the darn grate off the front.  For some reason, it's in two pieces.  The top single bar comes off first and then the bottom two screws release the rest of it.  You'll find that you have to bend the springs like a banana to get them in but they go in OK.  No special reason that I didn't put any in the outer two tubes other than I didn't think it would make much difference since little air comes through them but you will have the extra springs so put them in and let's see what happens!  )

I agree on the size.  If I had it to do over, I would get the 1200 and try to jam it into my little opening.


----------



## tjnamtiw (Dec 9, 2010)

thz123 said:
			
		

> I used a torch to bend mine, they bent like butter, very easy. Then I "aligned" the spring ends using a vise. I will try to put them in tonight. When I tried to insert them yesterday the tubes were good and hot. Last night I shined a flashlight into the tube and I could see where the ends of the springs were digging into the tube. It doesn't take long for the spring to get hot, since I had to get a pair of leather gloves on in order to pull the spring back out. It was hot after only a few minutes. I hope they go in easy now.



Sounds like you are good to go!  Tonight's the night!  I saw a night light with that saying on it!!  Should have bought it.


----------



## jackiec (Dec 9, 2010)

If you could not measure the temp. would you notice the extra heat?


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## thz123 (Dec 9, 2010)

Well they didn't fit into my Castile. I tried tube 9 and 6. They would only go in half way. Then I had to literally pull them out, the stove moved forward when I pulled. Yes I pushed, arched, and turned at the same time. I am worried if I force them in they will never come out. Its not me either, I am good at putting big things in a small hole, thats why I paid child support for 10+ years...LOL

My tubes taper in inside the tube @ about the 3 inch mark. They went in further than last night but I could only get them in 6 inches. Then they were totally stuck. I measured the outside diameter of the spring and its correct at 1.25". I did bend both ends all the way to the center and the outsides are alligned. Do they sell these springs with a slightly smaller diameter?

If yours go in easy and come out easy, your tubes are larger than mine...What could I be doing wrog?


----------



## tjnamtiw (Dec 10, 2010)

thz123 said:
			
		

> Well they didn't fit into my Castile. I tried tube 9 and 6. They would only go in half way. Then I had to literally pull them out, the stove moved forward when I pulled. Yes I pushed, arched, and turned at the same time. I am worried if I force them in they will never come out. Its not me either, I am good at putting big things in a small hole, thats why I paid child support for 10+ years...LOL
> 
> My tubes taper in inside the tube @ about the 3 inch mark. They went in further than last night but I could only get them in 6 inches. Then they were totally stuck. I measured the outside diameter of the spring and its correct at 1.25". I did bend both ends all the way to the center and the outsides are alligned. Do they sell these springs with a slightly smaller diameter?
> 
> If yours go in easy and come out easy, your tubes are larger than mine...What could I be doing wrog?



Yes, my tubes taper at the beginning too.  I almost bought the wrong size!  Are you turning the spring CLOCKWISE as you insert it?  That is the key.  I can't believe they would put a different size tube in some models.................. although they are made in China........................  By turning clockwise, you are actually winding up the spring and reducing its diameter so it goes in easier.  Without turning, it's not going in.


----------



## tjnamtiw (Dec 10, 2010)

jackiec said:
			
		

> If you could not measure the temp. would you notice the extra heat?



IMHO, yes you can.  I also see that I am overshooting my setpoint on my thermostat by an extra degree which means to me that it is putting out heat faster and there is more mass transferring heat after the fire is out.


----------



## thz123 (Dec 10, 2010)

Yes, I am turning it clockwise, and it gets really stuck. Tonight when I first put it in I thought great their going to go in, but then they got stuck. When it stuck I couldn't turn it in or out. I was using my hand to put it in, not a needle nose. I will try again, but it really scares me that it would never come out again or it may get stuck half way for good. How hard is it for you to take yours out? Maybe a needle nose pliers would do the trick? I really feel like a Da.


----------



## tjnamtiw (Dec 10, 2010)

thz123 said:
			
		

> Yes, I am turning it clockwise, and it gets really stuck. Tonight when I first put it in I thought great their going to go in, but then they got stuck. When it stuck I couldn't turn it in or out. I was using my hand to put it in, not a needle nose. I will try again, but it really scares me that it would never come out again or it may get stuck half way for good. How hard is it for you to take yours out? Maybe a needle nose pliers would do the trick? I really feel like a Da.



Oh, you've got to use more than your hands to put them in!  I use a large pair of pliers to get some torque on the spring.  It's really not that hard to get them in if you use the right tools.  By hand I imagine it would be tough.  Needle nose MIGHT work but I would go for something a little more hefty.  I don't mean to make it sound like you need to force them in.  it's just that you have got to wind up the spring a little bit and you can't do that by hand.


----------



## B-Mod (Dec 10, 2010)

I used regular pliers to put mine in. I would do it with the stove on as the tubes will be hot. Mine fit in pretty easy..........


----------



## Countryboymo (Dec 10, 2010)

I received a call back on the turbulators and without a decent sized order he would have to cut a piece of stock shorter than they usually do as small as the job would be.  He said it would probably be in the 250.00 range unless they found some scrap stainless to use.  He told me to call him back on a multiple order but I am not sure if it would be worth it.


----------



## tjnamtiw (Dec 10, 2010)

Countryboymo said:
			
		

> I received a call back on the turbulators and without a decent sized order he would have to cut a piece of stock shorter than they usually do as small as the job would be.  He said it would probably be in the 250.00 range unless they found some scrap stainless to use.  He told me to call him back on a multiple order but I am not sure if it would be worth it.



Well, that sucks!  But not totally shocking.  I guess it's time to do some mocking up to prove the concept!


----------



## skidozer (Dec 10, 2010)

does he have any longer ones that could be cut in half or cut down.


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## tjnamtiw (Dec 10, 2010)

jackiec got me thinking about turbulators versus the springs.  I was originally thinking of using the turbulators as a replacement for the springs; however, since the springs are actually increasing the heated surface area, wouldn't it make sense to put turbulators INSIDE of the springs?  I doubt that the turbulators will increase flow resistance by any appreciable amount so maybe that's the way to go.  What do you all think?


----------



## smalltown (Dec 11, 2010)

tjnamtiw I was cleaning my Castile freestanding last evening, and was thinking about the springs you inserted into the heat exchanger tubes. How long are the tubes?. Looking at mine they appear to go back about 12" then turn downward and drop lower out of sight? Are your springs about 12" in length?

Just re-read your post from the start and see that your cutting them about 9" in length. Still I wonder how far the tubes go in total length.


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## tjnamtiw (Dec 11, 2010)

smalltown said:
			
		

> tjnamtiw I was cleaning my Castile freestanding last evening, and was thinking about the springs you inserted into the heat exchanger tubes. How long are the tubes?. Looking at mine they appear to go back about 12" then turn downward and drop lower out of sight? Are your springs about 12" in length?
> 
> Just re-read your post from the start and see that your cutting them about 9" in length. Still I wonder how far the tubes go in total length.



yea, I wondered that my self.  I did some probing and ran into resistance at about 10" so I figured I'd make them a little shorter so I wouldn't block the flow as it made the turn.  Someone mentioned that the tubes are cast and I thought that, perhaps, they were cast into a manifold at the back so I didn't want to screw with that either.  so far so good.  I've been searching for some way to put some fins on the areas of the tubes that don't get swept by the pull rods.  Too bad they aren't copper!  Besides having 4 times the transfer efficiency of aluminum, I could also sweat on some fins easily.


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## smalltown (Dec 11, 2010)

Just thinking out loud here!
After looking down the tubes with a flashlight and seeing how dirty they are I have been trying to figure a way to clean them. I imagine that the dirt interferes with the heat transfer? Just now I thought what if I used a shotgun bore cleaning swab, and run it down the tubes by hand or in a drill bit:maybe it would fit on the flexible rods from my stove pipe cleaning kit, and go beyond that rear corner, and down?

Next spring (if I wait that long) when I do my final cleaning and remove the convection fan assembly I am going to place a mirror under the stove and look upwards to see if the other end of the tube assembly is visible. If I can a product called a "BoreSnake" could be pulled thorough from the bottom back of the stove through too the front grill.


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## ablejoy (Dec 11, 2010)

smalltown
 How about a bottle type brush I just tried my dryer brush tapered and worked good. Never looked down those tubes they were dirty.
The tube is 9" long from end to end plus 1"gap at the end = 10" total


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## tjnamtiw (Dec 12, 2010)

AZ Pellet Guy said:
			
		

> smalltown
> How about a bottle type brush I just tried my dryer brush tapered and worked good. Never looked down those tubes they were dirty.
> The tube is 9" long from end to end plus 1"gap at the end = 10" total



Wow, I wouldn't have expected them to be that dirty.  A bottle brush is a great idea.  Tomorrow I have got to find my bore scope which is a camera on a flexible shaft that puts a picture on a small screen.  Should be interesting if I can find it!


----------



## ablejoy (Dec 12, 2010)

Brush I used pulled a lot dust out, I am  going to hit the tubes with compressed air tomorrow.

The bore scope pictures should be interesting to see.


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## Countryboymo (Dec 12, 2010)

I use windex on a old piece of sock and tape it to a small rod.  If it does get loose I just reach in with a wood bit that has a threaded point and catch it and pull it back out.  I did snag a piece on the drill bit and use the drill and rag to clean it which started to really polish the pipe which I don't think is the hot ticket.  I also thought about searching for a flap disk sander that would fit in the tubes snug.  I would think an 80 to 120 grit spiral  in and out each tube would help create a touch of turbulence.  I blew the shop vac into each hole and WOW did the dust bunnies ever fly.  A leaf blower would do good this way also.  I still think a thin piece of copper or stainless with a nice gentle twist sitting in the tube would make the most difference.


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## tjnamtiw (Dec 12, 2010)

Countryboymo said:
			
		

> I use windex on a old piece of sock and tape it to a small rod.  If it does get loose I just reach in with a wood bit that has a threaded point and catch it and pull it back out.  I did snag a piece on the drill bit and use the drill and rag to clean it which started to really polish the pipe which I don't think is the hot ticket.  I also thought about searching for a flap disk sander that would fit in the tubes snug.  I would think an 80 to 120 grit spiral  in and out each tube would help create a touch of turbulence.  I blew the shop vac into each hole and WOW did the dust bunnies ever fly.  A leaf blower would do good this way also.  I still think a thin piece of copper or stainless with a nice gentle twist sitting in the tube would make the most difference.



I agree with the last part, for sure.  That would definitely help.


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## tjnamtiw (Dec 16, 2010)

Hey THZ123, did you ever get your springs installed?????  

I got my Ridgid SeeSnake out and took a look down the tubes.  They don't curve downward but, instead, end in a chamber or plenum.  I'm trying to experiment to find a decent way to record what I see and then put it on youtube with a link here.  Pretty interesting.


----------



## B-Mod (Dec 16, 2010)

Did you ever get any readings with your air flow thingy?


----------



## tjnamtiw (Dec 16, 2010)

B-Mod said:
			
		

> Did you ever get any readings with your air flow thingy?



To be honest, I'm not sure my 'air flow thingy'   :lol:  is what I was hoping for,  It is used to read wind speed outside.  With the springs in place I get about 5 mph and without them, I get about 3 mph.  So the springs have definitely restricted the flow somewhat causing a higher speed OR the spiraling of the air is causing strange things to happen to the readings.  I haven't really had time to compare areas with and without the springs to see if I can draw any conclusions such as 'are the springs really restricting total cfm?'  Have to also look at btu's coming out too but I'm not ready for that one!


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## thz123 (Dec 16, 2010)

No, I did not ever get the original set (diameter of 1.25") in. Last weekend I cut a piece of wood to gauge the I.D. of my tubes. Best I can tell, in the back my tubes are 1 1/8". So I purchased the springs that had an O.D. of 1.12", the wire size was a little smaller in diameter. I installed them last night.

I am currently having an issue with my convection blower motor, its squealing and grinding. I have a new part on order with my dealer, and it may take another week to get the part. My stove is 6 years old now. last night I ran the stove with the noise from the convection blower. I am not sure if it is running properly, since the convection blower is what brings the air to the burn pot. So I am not sure if the stove is getting its normal heat. 

The air coming out with the springs installed is for sure hotter, no doubt about it. I was running on high and couldn't keep my hand in front of the tubes - the air was that hot. I felt like my hands were going to get burned in that air stream. Normally, with out springs, I can keep my hands in front of the tubes no prooblem. 

The air coming out is spiraling around in a strange pattern, you can feel it by standing a few feet away.

I made a accordian style tubulator out of some aluminum roofing material. I tried to put that in last night, but couldn't get it in due to its flexibility, and I should have made it only 1" wide rather than 1 1/8". It keep tring to fold as I pushed in. I will try when its cold. It will only redirect the air, its too thin to absorb much heat.


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## tjnamtiw (Dec 16, 2010)

Sounds interesting, thz123.  Somewhere along the way, the diameters of the tubes must have changed or the Chinese wanted to use up some old tubing.  )  Sorry you had to double order springs but maybe someone else will be willing to buy them from you.  
You said convection blower but it sounds like you meant combustion blower.  That's got to cost a king's ransom for one of them from the dealer. 

I think your idea of a turbulator should work.  It doesn't have to absorb heat but just disrupt the flow so it is turbulent and mixes in the tubes.  Keep us informed on that one.  You're the first to put something like that in there so I'm interested.  If you put a hole through the leading end of the accordian, you could hook a piece of coat hanger (wish they still made metal ones as much as they used to!) in it and 'pull' it down the tube.


----------



## jackiec (Dec 16, 2010)

I have had the springs for a few days now and I have been holding off installing them because it seems improvements/adjustments are imminent. It would be nice to hear from a physics professor on how to maximize heat gain. It would also be nice to hear from a Quad engineer to get opinions and ideas. Surely, there is a scientific equation to achieve maximum results? Or should I just install the springs and start gaining heat?


----------



## thz123 (Dec 16, 2010)

Your correct combustion blower motor. The noise comes and goes, but its loud. Your right its a kings ransom, but cheaper than buying a new pellet stove. I have over 200 bags of assorted pellets in my garage. I love the heat from a pellet stove, so its getting fixed no matter what.

Exhaust blower motor $216
Gasket (if needed) $38
In home install $79.00 for one hour (I live in the country)
Total with Iowa 7% tax - $356.31

This is the only problem I have had, besides the tad pole gasket, in 6 years.

In a way I feel lucky that those are the only problems I have had, so i have no complaints. I don't know if they warrent the repair. This is pricing directly from the Quad dealer in town.


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## tjnamtiw (Dec 16, 2010)

thz123 said:
			
		

> Your correct combustion blower motor. The noise comes and goes, but its loud. Your right its a kings ransom, but cheaper than buying a new pellet stove. I have over 200 bags of assorted pellets in my garage. I love the heat from a pellet stove, so its getting fixed no matter what.
> 
> Exhaust blower motor $216
> Gasket (if needed) $38
> ...



You're right.  In the long run, $356 is a cheap price to pay for 6 years of enjoyment.  They really have no shame charging $36 for a gasket.  Amazing!
I wish I had 200 bags in my garage!  (At the price Lowes is charging up North).


----------



## tjnamtiw (Dec 16, 2010)

jackiec said:
			
		

> I have had the springs for a few days now and I have been holding off installing them because it seems improvements/adjustments are imminent. It would be nice to hear from a physics professor on how to maximize heat gain. It would also be nice to hear from a Quad engineer to get opinions and ideas. Surely, there is a scientific equation to achieve maximum results? Or should I just install the springs and start gaining heat?



Put them in and enjoy  It takes no time to take them back out.  Yea, I would love to get some 'official' info on our ideas.  I know that boiler people have used turbulators for many, many years but is there something better now?  I majored in physics............................................ 45 years ago!  I just threw out my thermodynamics texts this summer after no one at the garage sale would even TAKE them for nothing.  Same thing with 45 years of Nat'l Geo's.  Amazing that no one reads anymore.  Not even the library wanted my ~300 books


----------



## thz123 (Dec 16, 2010)

I love National Geographics, and don't care how old they are. I pay 10 cents a piece at St. Vincent De Paul for the ones I am interested in.

 I pay $4.00 a bag per ton for pellets, other wise they are $4.50 a bag. I have Blazers, White lighting, OHP (Ozark hardwood products), Indeck, and fuel King. 

Fuel Kings are awesome pellets, which were made in Waterloo Iowa, the plant has been closed for two years now. I scored 2 tons of Fuel king from our local feed supply store (they had 300 bags of old stock), and they delivered the 2 tons for $10.00. When unloading the driver and I did it by hand and he helped me stack the 2 tons in my garage! One hell of a deal! Fuel Kings came from a company that manufactured furniture, they made pellets from the saw dust. Saw dust is Oak, NO Bark! I love Fuel Kings, too bad they closed 2 years ago. So I couldn't pass on the fuel kings, Thats why i have over 4 tons of pellets in the garage. I started the season with about 250 bags, i probably have 225 bags. How does one become a member of the pellet pig club? I wonder if i qualify?


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## tjnamtiw (Dec 16, 2010)

It sure sounds like you qualify for pellet pig!  I just got off of the phone with my closest supplier and they want $4.97 a bag whether you buy one bag or one pallet!  Lowes is a little further away in Clemson, SC and they want $5.97 a bag.  That's just plain crazy.  I just opened another bag of these %^&&*** Carolina Wood Pellets and I swear that the AVERAGE length is 2" with many at 3"+.  I told my supplier that I was hoping he would get another source because these people clearly don't know what pellet burners have to deal with when they get pellets like that.  I've been fighting my Castile all day with bridging at the top of the chute.

My Nat'l Geo's were a complete set from June of 1965 to present.  Now you can get the entire collection on DVD's!


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## G00k (Dec 17, 2010)

Countryboymo said:
			
		

> I think even one small piece of thin flat stock in a slow spiral would make a huge difference.   I am thinking of what material to use and how or where to get the nice even swooping twist.



Here I am again, the aluminum foil kid!

If one of the aims here is to defeat the laminar effect, *how much of the airflow in the tube needs to be affected* to better mix the heated air?  

For example, if it doesn't need to be a strip as wide as the inside diameter, (say, for an inside diameter of 1.25 inch, maybe a strip of .75 inch wide and as long as the length of the pipe)  Maybe aluminum foil folded over several times into the correct width for strength, folded back at the inside edge to prevent being forced open by the air flow (no restriction), and maybe a gentle twist to generate enough turbulence to disrupt the laminar effect.  

Everyone has aluminum foil, and it could be used to test the hypotheses.  I will try it, but I don't have much access to the exhaust area or (more importantly) the test equipment to properly gauge the result.



Don't laugh.  I've seen testing laboratories.


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## tjnamtiw (Dec 17, 2010)

Yes, I have been more involved with DOT testing lab in Pa and I shake my head in disbelief at how ignorant they were of testing methods that manufacturers were required to use.  

I'm not sure how stiff you could get the aluminum foil but it sure might surprise me.  Worth a try.  Isn't the exhaust on your Castile just behind the cast door?  I have an insert so maybe the free standing one is different.  There have been quite a few good ideas here!


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## G00k (Dec 17, 2010)

Yeah, it's behind the door.  Like I said, I'll try it and report back how it feels to me.  Maybe a meat thermometer of some other crude method...


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## tjnamtiw (Dec 17, 2010)

G00k said:
			
		

> Yeah, it's behind the door.  Like I said, I'll try it and report back how it feels to me.  Maybe a meat thermometer of some other crude method...



Great!  A meat thermometer works as long as it doesn't sit on the tube.


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## tjnamtiw (Dec 18, 2010)

One thing I am learning from these experiments is that evidently the Chinese have no quality control (big surprise).  One person can't fit the springs into the tubes and had to order 1/4" smaller diameter and another one just had the springs slide right down the tubes to the plenum!!


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## SmokeyTheBear (Dec 18, 2010)

tjnamtiw said:
			
		

> One thing I am learning from these experiments is that evidently the Chinese have no quality control (big surprise).  One person can't fit the springs into the tubes and had to order 1/4" smaller diameter and another one just had the springs slide right down the tubes to the plenum!!



That means that HHT/Quadrafire also has no quality control either.


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## tjnamtiw (Dec 18, 2010)

SmokeyTheBear said:
			
		

> tjnamtiw said:
> 
> 
> 
> ...



10-4 on that one, good buddy!


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## G00k (Dec 18, 2010)

So far, I'm trying the foil experiment on two tubes only.  A full width (~12") of foil approx 15' long, folding so that the 15" dimension folds to ~ .5 - .75 inch strip.  Folded the "hot end" back about .5 in.  At the "cool" end, I peeled a tab down about .5" to keep it from sliding out of reach into the tube.   I twisted the resulting strip to resemble the "turbulators" from the other site's picture.  I only got about 5 twists on it.

Once the blower turned on, I could feel a distinctly lower rate of air flow using the two center tubes.  I pulled the strips out and put them into two of the tubes that had the most flow.  It knocked the flow down in thise tubes appreciably*, BUT the two end tubes (either end) started having more air flow (They had much less flow originally).  Perhaps one can tune the total heat output doing this.  

Has anyone using the spring inserts noticed a similar effect?

*The test equipment I'm using for the moment is just my hand (relative airflow).


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## tjnamtiw (Dec 18, 2010)

G00k said:
			
		

> So far, I'm trying the foil experiment on two tubes only.  A full width (~12") of foil approx 15' long, folding so that the 15" dimension folds to ~ .5 - .75 inch strip.  Folded the "hot end" back about .5 in.  At the "cool" end, I peeled a tab down about .5" to keep it from sliding out of reach into the tube.   I twisted the resulting strip to resemble the "turbulators" from the other site's picture.  I only got about 5 twists on it.
> 
> Once the blower turned on, I could feel a distinctly lower rate of air flow using the two center tubes.  I pulled the strips out and put them into two of the tubes that had the most flow.  It knocked the flow down in thise tubes appreciably*, BUT the two end tubes (either end) started having more air flow (They had much less flow originally).  Perhaps one can tune the total heat output doing this.
> 
> ...



I can answer that question about changing airflows IF I ever get off my lazy butt and use my airflow meter with and without the springs.   :red:   Football time now, though.  My priorities are slightly warped.


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## G00k (Dec 18, 2010)

No, you priorities are okay.  I don't need heat when in the heat of battle!   Go RAVENS!


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## tjnamtiw (Dec 19, 2010)

Well, now I know why they have half times!  Gave me time to take some airflow measurements with and without the springs in place in tubes 2 thru 9, with 1 being on the left side.  First with the stove convection fan on high WITH THE SPRINGS  and then next to those readings are the readings with no springs in any tubes.  All measurements taken with my Dwyer wind speed meter resting against the side of the tube and the frame so that all tubes were presented with the same angle to the measuring tube.   Also, the measuring tube end was presented to the center of the tube.  All readings are in mph.

Tube   w/spring  wo/spring
1           2.9**        4.7
2           8              7.5
3           6.5           4.5
4           7.5           4.6
5           6.7           3.2
6           6.4           3.6
7           6.5           4.8
8           6.7           6.5
9           5.5           4.8
10         4.5**        0.0

** = no spring

One thing to notice is that the springs force airflow through the final #10 tube, so we get heat from it whereas we get none without the springs.  
Also, in all tubes except the first one, the speed of air increased with the springs in place.  I think this could be expected since we are, undoubtedly, reducing the effective diameter to some extent.  However, with the higher speed we are blowing the hot air further into the room plus the springs, IF FITTING TIGHTLY, have heated up and present more surface area to the turbulent flow.  Now we need a thermodynamic whiz kid to analyse all this!


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## B-Mod (Dec 19, 2010)

tjnamtiw said:
			
		

> Now we need a thermodynamic whiz kid to analyse all this!




And here I thought that was you, lol...........


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## tjnamtiw (Dec 19, 2010)

B-Mod said:
			
		

> tjnamtiw said:
> 
> 
> 
> ...



ha ha ha.  Yea, maybe 40 years ago before I destroyed most of my brain cells with torpedo juice in the Navy (190 proof) and an 'occasional' sip after that!  Maybe we can find something we can use by googling.  We shall see.  Those readings were interesting, though.

I was really surprised that the aluminum foil turbulator retricted flow so much.  Gotta try that with some sheet metal.


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## jackiec (Dec 19, 2010)

Installed the springs in Santa Fe insert today. I can still hold my hand in front of the tubes but it is definitely hotter. I can feel the heat being thrown from 10 feet away now and not before. Skytech remote temp was overshot by a degree....Never before has that happened.


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## B-Mod (Dec 19, 2010)

I think the key (using my hand as a flow meter) is leaving out the springs in the outer pipes. I put them all in and it killed off some flow. Keep in mind I only have 8 tubes total, so your results could differ...........


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## tjnamtiw (Dec 19, 2010)

jackiec said:
			
		

> Installed the springs in Santa Fe insert today. I can still hold my hand in front of the tubes but it is definitely hotter. I can feel the heat being thrown from 10 feet away now and not before. Skytech remote temp was overshot by a degree....Never before has that happened.



I noticed the same thing with my Skytech!  I actually turned the span down from 2 degrees to one degree.  Even at that, it overshoots by 2 degrees before all the heat is out of the stove! I'm glad you got the springs in successfully!


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## tjnamtiw (Dec 19, 2010)

B-Mod said:
			
		

> I think the key (using my hand as a flow meter) is leaving out the springs in the outer pipes. I put them all in and it killed off some flow. Keep in mind I only have 8 tubes total, so your results could differ...........



You are probably right seeing that there is no airflow through the  last tube without springs and a 'moderate amount' with springs in the other tubes.  If a spring was in there,.....................  Hmmmm, maybe I'll move one over there just to see what happens.  I shut it down for the night in the family room.  The Castile is a lot easier to play with than the Sante Fe with that aggravating grill on the front.  I'd just as soon leave it off since it restricts the flow, but the 'boss' says 'No way, Jose'......


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## B-Mod (Dec 19, 2010)

Boss? I have one of those at work, none at home, lol. (Crap here she comes again)

I will get you those pics tomorrow when I shut the stove down. I did a cleaning on it today, and was then in a rush to get the stove back on to keep it toasty in here, only a high of 10 degrees here......


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## tjnamtiw (Dec 19, 2010)

B-Mod said:
			
		

> Boss? I have one of those at work, none at home, lol. (Crap here she comes again)
> 
> I will get you those pics tomorrow when I shut the stove down. I did a cleaning on it today, and was then in a rush to get the stove back on to keep it toasty in here, only a high of 10 degrees here......



No problem.  Tomorrow's going to be 50  Heat pump time again but below freezing every night for the next week so I'll use about a bag a day between the two stoves.


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## thz123 (Dec 19, 2010)

Using springs in tubes 5 & 6, new meat thermometer, glove on hand, touching no metal. Castile running on medium. Using an all oak pellet (Fuel King pellets from Waterloo, Iowa). My name for them is "Rocket Fuel"! (Fuel King Pellets have been out of business for 2 years now, I happened to find 2 tons this year.)

springs         no springs
210              200 degrees

Using Indeck Brand Pellets, Ladysmith Wisconsin (I really don't like these - smoldering ash build up in firepot, a lot)
springs         no springs
200              190 degrees

It feels to me that the air is restricted a bit, except when running on low. 
My home made trubulator restricted air flow too.
Thats my 2 cents worth.


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## tjnamtiw (Dec 19, 2010)

Nice start,thz123.  It 'feels' like the air is restricted but my readings above show it is actually faster.  I think, as b-mod said, it's because the air is swirling and maybe spreading out kinda like taking the choke out of a shotgun.  I'll be interested when you put the rest of the springs in to see the readings.  Too bad about the turbulator.  I don't think we've given up on that one yet.

I took the spring out of tube 2 and put it in the empty tube 10 to see what happens.  It WAS 4.5 mph and with the spring, it went up to 5.0 mph, so there was a little improvement there.


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## smalltown (Dec 20, 2010)

My only wish for the Castile Quad would be for the convection fan operation to be quieter. I was wondering after you install the springs is there any change in the noise level.

P.S. I am not sure if all the noise is the actual combustion fan assembly running or the way Quad pushes the air through the tubes or a combination. Just imagine how great these stoves would be if we could quiet down these noises.


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## jackiec (Dec 21, 2010)

The number one reason I chose SantaFe/Castile Insert was because I found them to be the most quiet operating insert on the market. It could be that they are smaller than most others. I wonder if something is wrong with yours?


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## tjnamtiw (Dec 21, 2010)

I haven't noticed any increase in noise level with the springs inserted.  Has anyone else?  The Castile's cast front end sure doesn't help the issue since it partially blocks the passage of air.  In fact, if I'm not 'forced to make it look pretty'......., I leave the door open to get better airflow.


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## smalltown (Dec 21, 2010)

jackiec  No nothing wrong here: no bearing noises etc. It's just the blowing of air noise I think. They are just so quiet before the convection blower kicks in that's all.


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## YooperD2 (Dec 21, 2010)

On my Santa Fe the noise level stayed the same after I installed the springs. I also find these stoves are somewhat loud, like most forced air stoves.


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## thz123 (Dec 21, 2010)

No added noise with the springs in. I also leave my cast door open for more heat, when the grand kids arn't around. I have a set of springs that are OD 1.25", that I will sell to someone at my cost plus shipping.


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## tjnamtiw (Dec 21, 2010)

thz123 said:
			
		

> No added noise with the springs in. I also leave my cast door open for more heat, when the grand kids arn't around. I have a set of springs that are OD 1.25", that I will sell to someone at my cost plus shipping.



Hope you can sell them for a reasonable % of what they cost you.  Shipping should be minimal since they are already cut to length.  They would fit in the small Priority Mail box, I think.


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## G00k (Dec 23, 2010)

THZ123, 

How much you want for them?  Shipping to Parkton, Maryland? 


And Merry Christmas to all y'all!


G00k


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## thz123 (Dec 24, 2010)

I paid $18 shipped to my house. I believe they will fit in the USPS priority box, and thats I think $4.95 to you. So a total of $22.95. Thats a deal because you won't have to cut them or turn the ends in, which I did with these using a torch. I have 8 of them cut to 9". Let me know. Its snowing here and the satilite may go out, we have a winter storm expecting 8+" . So if I don't get back to you quickly thats why.


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## skidozer (Jan 11, 2011)

I just found gold, I was in the back storage room at work and found some old turbulators.
They are stainless about 3/4" wide and 8 feet long they were going to be thrown out today.
going to measure the tube length and give them a try. I wish I had more spare time I have data loggers for up to 80 channels of thermocouples.


----------



## tjnamtiw (Jan 11, 2011)

skidozer said:
			
		

> I just found gold, I was in the back storage room at work and found some old turbulators.
> They are stainless about 3/4" wide and 8 feet long they were going to be thrown out today.
> going to measure the tube length and give them a try. I wish I had more spare time I have data loggers for up to 80 channels of thermocouples.



Oh man, you lucky b^&^rd!  The data logger would be the ticket for great information.  Can't wait to see what you find out.  Keep us posted, please.

Things are still clicking along here.  I just did the B-Mod mod  :cheese: to my Castile to keep the blower on high no matter what the feed rate is.  It worked good over nite and didn't use nearly as many pellets to keep the room at temp even though the temp outside is COLD and windy.


----------



## skidozer (Jan 11, 2011)

where do I find info on the B-MOD?

Im going to cut one up at lunch time and see how they fit.


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## tjnamtiw (Jan 11, 2011)

skidozer said:
			
		

> where do I find info on the B-MOD?
> 
> Im going to cut one up at lunch time and see how they fit.



B-Mod's a regular on here.  He has an older Sante Fe.  I posted this on another thread that explains what I did. >

Yesterday I finally got around to making the small modification that B-Mod has been talking about in several posts.  That is, he rewired the stove (Sante Fe) so that there was always 110 volts going to the #1 snap disk, which controls the convection blower.  One complaint I have with the stoves is that on low (especially) and medium feed rates, the blower is just too darn slow and a lot of heat isnâ€™t getting transfered to the tubing.  Now, with the convection blower on high, I am blowing a lot of air strongly out no matter what the feed rate is.  I am able to heat the same room on medium that I was on high.  Another side effect is that on medium the combustion blower slows down and gives the combustion air more time to transfer heat to the tubing rather than blowing it out the exhaust.  With the air moving faster inside the tubes (with my installed spring mod), I am, I believe, sucking more heat out of the tubes and creating a larger delta T across the tube/combustion air interface and more heat transfer.
All of this will have to be measured when I get a chance.

For those like Foos, who are having problems cutting back on the feed rate, this presents a solution.  Since Iâ€™m on medium, my feed rate is reduced to a more reasonable level.  For Foos, this might bring his feed rate down to where he has a â€˜normalâ€™ flame height and no build up of pellets.

Since on my Castile insert and the Sante Fe the only 110 volt feed wire that is fused is the one going to snap disk #3, this is where I had to get my power.  The gauge of the wire going to the snap disc and the wire originally feeding snap disk #1 is the same.  I found the FEED side of the wire going to snap #3 and made up a harness that would plug into that feed wire after disconnecting it from the snap disk.  The other end is a Y that connects back to snap disk #3 and to the FEED side of snap disk #1.  The wire I removed from snap disk #1 is tapped off and left to hang in the stove.  By tapping the power BEFORE the snap disk #3, I am not altering the function of or bypassing its very important function of shutting down the stove in the event of a drop chute fire.


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## G00k (Jan 12, 2011)

You DID take pictures of it, didn't you?  This sounds like a logic mod to make.  I hope it does everything you want it to.  Keep us posted, please.


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## tjnamtiw (Jan 12, 2011)

You have a Castile too so you know where snap disc #3 is.   %-P   No way in heck can I get a picture of that!  I should have taken pictures of the springs in the tubes.  Did you do that mod?  I also relocated snap disc #1 from low on the side to the top front corner of the side so it senses the 110 degrees quicker and turns on the fan.  I'll have to take pictures of those two things and post.


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## tjnamtiw (Jan 13, 2011)

Here are pictures of my Castile with my springs in the heater tubes and with one view where I pulled the spring part way out so you can see what it looks like.  Also you can see how I bent the end for a better grip with a pair of pliers.  That way I can twist them into the tubes.  You can see if you look closely that the ends of the tubes are tapered and don't quite touch the first part of the spring.
The last picture shows a side view of the firebox.  You can see that I moved and replaced snap disc #1 with an adjustable version as suggested by B-Mod.  Also you can see that I have run a 110 volt line directly to it rather than the variable voltage line that is seen taped off.


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## skidozer (Jan 13, 2011)

I got the turbulators installed last night.
I did not get a chance to do any scientific measurements with the snow we got, I was out on snow removal duties.

The most notible thing I noticed is it is now much warmer in the perimiters of the room.
I have the stove in a 20 by 24 room with a short cathideral ceiling. I have a window on the far side of the room with a indoor outdoor thermometer, I used to see about a 4 0r 5 deg diff between that reading(its by a window) and one I have in the center of the room. Last night it was cold 12f and that therm was only 1 deg different.

The room also seemed to come to temp a bit quicker than before from 60 to 68.

I took a couple pics like the ones above of the springs, I will try to post them later.


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## tjnamtiw (Jan 13, 2011)

Well, that sure sounds encouraging  It has got to be a step in the right direction.  Can't wait for some more data.


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## thz123 (Jan 13, 2011)

Hey tjnamtiw, I would like to complete B-mods modification, based on your description, however I am not electrically inclined and I didn't follow your explaination about how to wire it so the fan is on high constantly. Can you help with a easier description? Maybe a better picture?Thanks again for all your help, Tom


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## tjnamtiw (Jan 13, 2011)

thz123 said:
			
		

> Hey tjnamtiw, I would like to complete B-mods modification, based on your description, however I am not electrically inclined and I didn't follow your explaination about how to wire it so the fan is on high constantly. Can you help with a easier description? Maybe a better picture?Thanks again for all your help, Tom



If you're not electrically inclined, then you probably don't have crimpers for wire terminators, a voltmeter or the parts either.  I am trying to be nice  :red: but maybe you shouldn't do it.....  If you have a friend who has the tools, get him to make up a Y harness from 20 gauge wire for you with a female spade connector at each end and about 24" long.  Out of one end also crimp in a short length of wire about 6" long and put a male spade terminal on it.  
Now you've got to reach around behind the stove and (OH, UNPLUG THE STOVE) find snap disc #3 and pull off both connectors.   Bring them around front so you can measure the voltage.  Plug the stove back in but don't turn it on that it calls for heat.  Connect one end of the voltmeter to the frame of the stove anywhere and with the other voltmeter lead find out which of the snap disc #3 terminals has 110 volts.  Label it with a piece of tape.  Plug the male spade lug on your new wiring harness you made up into that female end.  Then take the female end on your new harness that is near the male end you just used and attach it to snap disc #3.  Plug the other connector of the original leads onto the other terminal of the snap disc.
Now go to snap disc #1 and do the same thing to find out which wire has 110 volts going to it.  Since this one is a normally open contact, you can just probe the two sides of the snap disc.  Unplug the stove and remove the wire that had the 110 volts and tape it up securely.  You won't use it.  Connect the other end of the new wiring harness that is 24" from the other end to the open terminal on snap disc #1.  You're done.  Plug it back in and hope it doesn't smoke!!  

I'm no lawyer but I have to say that you do this ALL AT YOUR OWN RISK!  I CANNOT CONTROL WHAT  YOU DO OR HOW YOU DO IT!   %-P 

Now you see why a picture would not tell the story.


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## B-Mod (Jan 15, 2011)

tjnamtiw, glad you find my mod works well for you also. My little quad is just burning happily along, keeping the whole house warm. Your spring mod is working great also. Got some really cold air headed this way again next week. Not much else new here, just dead of winter here, and not much snow. Might actually drag out a snowmobile today to make a few tracks in the yard, lol.............


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## tjnamtiw (Jan 15, 2011)

Yea, it works great, B-Mod.  I haven't been on a snowmobile in about 30 years!  That used to be fun up in Pa running across corn fields at night about 60 mph hoping and praying there weren't any barb wire fences up ahead  Funny how a few beers can make you invincible.    ;-P


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## BradH70 (Oct 19, 2012)

Just ordered some springs. I'm also going to take a look at doing the B-Mod for the convection blower.


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## BradH70 (Oct 24, 2012)

Got my springs today. Just in time for daytime temps to go back into the 60's and 70's Once I get them in and it is cold enough to run the stove again, I will post a report on results.


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## Harvey Schneider (Oct 24, 2012)

I worked on high speed centrifuges for a few years. In the process I learned a little about controlling air flow. I want to suggest that you experiment with the amount of spring that you install. Sometimes less is more. You only need to introduce some turbulence in the flowing air. Flowing air can't really be directed where to go. If you add too much resistance to flow near the walls the air will flow down the open center or may not flow at all. 
I one of our designs it only took a twisted piece of aluminum in the flow path to cause the turbulence we needed to get good heat transfer. In another design a wad of stainless window screen was stuffed into the tube. It takes some experimentation to determine the optimum amount of turbulence for good heat transfer. A flat piece of aluminum the width of the tube diameter and a few inches long with a quarter twist should work well in this situation. 
I hope this is helpful.


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## BradH70 (Nov 12, 2012)

Ok, so I finally had a chance to get the springs into the heat exchanger tubes yesterday. I have to admit that I did not get the results that I had hoped for or the results that some of the other have. What I noticed was a decrease in air flow out of the heat exchanger tubes and an increase in the exhaust temp by about 8 degrees. My stove has 8 tubes versus the 10 tubes of the new stoves so maybe that is were the issue is. Either way, I'm going to remove them and keep the stove stock for now.


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## SmokeyTheBear (Nov 12, 2012)

Brad,

Can you post a picture of your stove looking at the tubes with the spring installed.  It sounds like you are blocking the air flow and that can happen if there isn't enough of a gap between each section of the coil.   Blocking air flow will result in exhaust temperature rise.  The goal with the springs is to make the air path both more turbulent and the heat transfer area of the exchanger larger.


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## BradH70 (Nov 12, 2012)

Hi Smokey. I will get a picture posted tonight. I am pretty sure that the main issue is lower air flow. The springs consume a good portion of the volume of the heat tubes, maybe a spring with less twists over its length would be better.

Either way, I am going to take them out. My next step is to start to decide on a new control box or not. Mine is dated 2 7 2001 so I know that it is not running the stove nearly as efficiently as the new control boxes do. See thread https://www.hearth.com/talk/threads/quad-castile-combustion-fan.92374/

The stove does run good. No CSS to speak of and the heat is decent but I think it could be much better if the combustion fan speed was being controlled based on the heat setting.

And it is about as loud as a freight train, but then again I'm used to my M55 (pre-blower upgrade).


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## SmokeyTheBear (Nov 12, 2012)

I saw that other thread and didn't want to get into the middle of the control box argument. Your box is likely in the era of we are trying to perfect things.

I notice whenever I search for Quad Control Boxes there are quite a number of them out there for the various models and even for the same model stove so something was changed and more than one change took place.

You can see the same thing with other stoves made by other manufacturers(kit builders).

ETA: I'm following this thread because I can make the same mods to my unit if I feel like it.


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## openat60 (Nov 25, 2012)

tjnamtiw said:


> If you're not electrically inclined, then you probably don't have crimpers for wire terminators, a voltmeter or the parts either. I am trying to be nice :red: but maybe you shouldn't do it..... If you have a friend who has the tools, get him to make up a Y harness from 20 gauge wire for you with a female spade connector at each end and about 24" long. Out of one end also crimp in a short length of wire about 6" long and put a male spade terminal on it.
> Now you've got to reach around behind the stove and (OH, UNPLUG THE STOVE) find snap disc #3 and pull off both connectors. Bring them around front so you can measure the voltage. Plug the stove back in but don't turn it on that it calls for heat. Connect one end of the voltmeter to the frame of the stove anywhere and with the other voltmeter lead find out which of the snap disc #3 terminals has 110 volts. Label it with a piece of tape. Plug the male spade lug on your new wiring harness you made up into that female end. Then take the female end on your new harness that is near the male end you just used and attach it to snap disc #3. Plug the other connector of the original leads onto the other terminal of the snap disc.
> Now go to snap disc #1 and do the same thing to find out which wire has 110 volts going to it. Since this one is a normally open contact, you can just probe the two sides of the snap disc. Unplug the stove and remove the wire that had the 110 volts and tape it up securely. You won't use it. Connect the other end of the new wiring harness that is 24" from the other end to the open terminal on snap disc #1. You're done. Plug it back in and hope it doesn't smoke!!
> 
> ...


 

Does this look right for my own knowledge...and if it is might make it easier for some...Hopefully I decipherd your instructions right.


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## tjnamtiw (Nov 25, 2012)

openat60 said:


> Does this look right for my own knowledge...and if it is might make it easier for some...Hopefully I decipherd your instructions right.


 
That should do it!  Basically you are feeding both the convection fan snap disk and the safety snap disk with the same fused 110V supply.


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## tjnamtiw (Nov 25, 2012)

SmokeyTheBear said:


> Brad,
> 
> Can you post a picture of your stove looking at the tubes with the spring installed. It sounds like you are blocking the air flow and that can happen if there isn't enough of a gap between each section of the coil. Blocking air flow will result in exhaust temperature rise. The goal with the springs is to make the air path both more turbulent and the heat transfer area of the exchanger larger.


 
That was also my aim.  I see what Harvey was saying and it may bear some fruit to play around with the turns and other mods.  The last thing he was talking about was a twisted piece of metal which is the turbulator that we also have in there!  From my studies, they helped the situation too.  The best way, in my opinion, to see if you are extracting more heat is to monitor the exhaust temperature at the same exact spot on the exhaust side of the combustion blower under steady state conditions.  Both experiments yielded a lowered temperature meaning less heat up the flue.


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## openat6 (Nov 25, 2012)

tjnamtiw said:


> That should do it!  Basically you are feeding both the convection fan snap disk and the safety snap disk with the same fused 110V supply.





tjnamtiw said:


> That should do it!  Basically you are feeding both the convection fan snap disk and the safety snap disk with the same fused 110V supply.



Just conversation the fuse is else where on the harness, there was no mention of a fuse in your instructions??


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## openat6 (Nov 25, 2012)

And also can you break down the springs and the blower mod for the slower folk in he room one more time.  Haha.   What they do and what the gain in general.


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## tjnamtiw (Nov 25, 2012)

openat6 said:


> Just conversation the fuse is else where on the harness, there was no mention of a fuse in your instructions??


I was referring to the main system fuse.  
The mods are, I think, pretty well spelled out in this LOOOOONG thread plus there's another thread about 'turbulators' somewhere.


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## openat60 (Nov 26, 2012)

tjnamtiw said:


> I was referring to the main system fuse.
> The mods are, I think, pretty well spelled out in this LOOOOONG thread plus there's another thread about 'turbulators' somewhere.


 
haha  i was trying to cheat...


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## tjnamtiw (Nov 26, 2012)

openat60 said:


> haha i was trying to cheat...


I just didn't have the stamina to go all the way through the experiments.    I'm not saying that what we did is the BEST solution to getting more heat out.  It's just A solution that does indeed extract more heat.  There very well could be other ways but the smooth tube heat exchangers have been around and UNIMPROVED for probably 50 years in fireplaces.  You know the ones that you build the fire on top of and the tubes curve back out into the room.  There's a small blower on them.  
Why they couldn't extrude tubes with fins internally and externally is beyond me!  What an improvement it would make in efficiency.  I guess the Chinese aren't as ingenious as we think they are.  They just stole another old idea!


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## Augmister (Nov 27, 2012)

I have been following this thread for about a year and this is my first comment.  I will disclose that I am not an engineer and at best, a poor tinker.  The goal is get the most heat out of the stove and into the room with as little loss as possible from the heat generated in the fire box.  I agree, at best, some sort of "add on" can achieve an increase of heat transfer, over the stock (current) design, as you are mindful that you only can work with what you have (the current design of the two QF stoves).   By adding geometry (springs) to the tube walls you immediately improved your heat transfer from your stove to the room.  Here, it is most important that you have the best contact possible between the tube wall surface and your added geometry to achieve maximum heat transfer.  There has been a lot of suggestions about the materials for the added geometry (springs) but what is important to remember is that thermal conductivity and heat transfer are not linear.   The more thermally conductive the material is, is not directly related to the amount of heat transfer the specific application calls for to move the heat from point A to point B.   All you trying to do is moving heat as efficiently as you can from point A to point B.   You are not going to move more heat by using copper instead of aluminum or a stainless steel.   You just need enough thermal conductivity to satisfy the requirements of your application.   If you were to make springs of all three materials and measure them, the temperature measured at ends of tube would be amazingly close.   Think of it this way, you are cooling the stove by dumping the hot air that doesn't go up the flue, into a room.  You are turning a straight tube into a more efficient heat sink with forced convection.    Air flow is the other critical factor (as I see you have learned from the blower mods you have made to the snap disks).   If you decrease the airflow by adding resistance, you don't transfer as much heat to the room.   I think what you have done is excellent and has made me think of this "experiment" a great deal for a long time.   What is the OD (thickness) of the spring material you are using?   I am trying to get a metal fabricator I know to produce an insert coil with a smaller OD thickness but more twists which will increase air flow but not decrease the heat transfer surface between coil and tube.  Or, keep the same OD of your current spring and decrease the number of coils.  I would like to get those metrics and then move ahead with tuning those tubulator rods inside the coils.   As you have already seen with the work you have done, tjnamtiw, what seems as a nominal increase in efficiency makes a big difference.


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## tjnamtiw (Dec 24, 2012)

tjnamtiw said:


> That should do it! Basically you are feeding both the convection fan snap disk and the safety snap disk with the same fused 110V supply.


Looking at your diagram again, what you WANT is to feed the #1 snap disk from the INPUT side of the #3 safety snap disk and NOT its output side.  This way, if you have an overheat condition and #3 opens up, you will still have the convection fan running to cool the stove down to safe levels.  You don't want to feed a snap disk from another snap disk.


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## Andy1 (Jan 7, 2014)

How do you go about increasing the speed of the convection blower without increasing pellet feed?


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## Andy1 (Jan 7, 2014)

Minister of Fire, you may want to take a look at a heat transfer method other than steel springs good test though it may be.  With the close proximity of steel to aluminum at elevated temperatures you are encouraging significant galvanic or catholic corrosion of the aluminum tubes. I'd be less concerned if the tubes were steel but as it is the tubes will go away if the springs are left in place. The ideal replacement is a 11/4" spiral fin this would restrict air flow but I doubt this would do anything but positively impact performance.


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## tjnamtiw (Jan 7, 2014)

Andy1 said:


> Minister of Fire, you may want to take a look at a heat transfer method other than steel springs good test though it may be.  With the close proximity of steel to aluminum at elevated temperatures you are encouraging significant galvanic or catholic corrosion of the aluminum tubes. I'd be less concerned if the tubes were steel but as it is the tubes will go away if the springs are left in place. The ideal replacement is a 11/4" spiral fin this would restrict air flow but I doubt this would do anything but positively impact performance.


That IS interesting, Andy.  The next time the stoves are down for cleaning or warm weather, I'll pull a couple of the springs and take my inspection camera and feed it in the tubes to see if there is any evidence of corrosion.  I would think after a couple of years that, if it's happening, I would see a spiral pattern of corrosion.  Thanks for the warning.  I'll feed back for the others who have made this mod.  Worst cast would be to give the springs a 1/4 turn to put the contact at a different spot on the tubes.
Oh, thanks to one of the other guys, I have the twisted spirals inside of the springs!  But filling the space completely with 1 1/4" spirals would be good but you wouldn't get the contact area that the springs afford.  We're looking for anything to improve the caveman technology in the standard Quads and many others.  All suggestions are welcome.


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## Andy1 (Jan 7, 2014)

I'm interested to hear the result, I'm all about improving the efficiency of the Castile and I firmly believe they could be more efficient than they are either by modifying the tube or installing a secondary heat exchange?? I did see in an earlier thread that the convection blower control could be modified so it ran high all the time. How do you do this? Also do you know what the selector switch does located on the control board? From what I can see there are four positions. Many thanks Andy


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## Andy1 (Jan 7, 2014)

BTW, just pulled the convection blower off of the back of the stove and cleaned all the crud out of it. What a difference that made to the stove noise.


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## PoolGuyinCT (Jan 7, 2014)

tjnamtiw said:


> Yea, it works great, B-Mod.  I haven't been on a snowmobile in about 30 years!  That used to be fun up in Pa running across corn fields at night about 60 mph hoping and praying there weren't any barb wire fences up ahead  Funny how a few beers can make you invincible.    ;-P





Being drunk & 30 years younger... Great combo!


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## Harvey Schneider (Jan 7, 2014)

tjnamtiw said:


> That IS interesting, Andy.  The next time the stoves are down for cleaning or warm weather, I'll pull a couple of the springs and take my inspection camera and feed it in the tubes to see if there is any evidence of corrosion.  I would think after a couple of years that, if it's happening, I would see a spiral pattern of corrosion.  Thanks for the warning.  I'll feed back for the others who have made this mod.  Worst cast would be to give the springs a 1/4 turn to put the contact at a different spot on the tubes.
> Oh, thanks to one of the other guys, I have the twisted spirals inside of the springs!  But filling the space completely with 1 1/4" spirals would be good but you wouldn't get the contact area that the springs afford.  We're looking for anything to improve the caveman technology in the standard Quads and many others.  All suggestions are welcome.


Thermal contact between a round spring and an enclosing cylinder is never very good. Theoretically there is only a line of contact. As a result heat transfer is not usually through the spring. The spring serves primarily as a means of creating turbulence. The turbulence improves heat transfer from the cylinder to the air. In a design that I worked on many years ago we used a twisted piece of aluminum dropped into the pipe to enhance turbulence. Creating too much turbulence hurts heat transfer because it reduces the volume of air moving through that path. As with all engineering, it's a juggling act.


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## tjnamtiw (Jan 7, 2014)

Andy, what kind of stove do you have?  You should put it in your signature so all can see.  The high speed convection mod was first done by B-Mod and I copied him and added the springs and 'turbulators'.  To get the fan to always be on high, I feed the snap disk for the fan (purple wires) from the infeed side of snap disk #3 instead of from its normal feed.


Harvey Schneider said:


> Thermal contact between a round spring and an enclosing cylinder is never very good. Theoretically there is only a line of contact. As a result heat transfer is not usually through the spring. The spring serves primarily as a means of creating turbulence. The turbulence improves heat transfer from the cylinder to the air. In a design that I worked on many years ago we used a twisted piece of aluminum dropped into the pipe to enhance turbulence. Creating too much turbulence hurts heat transfer because it reduces the volume of air moving through that path. As with all engineering, it's a juggling act.


You're right, it is a line contact but a contact none the less.  Most benefit comes from the turbulence.  Most of my experience was with heat transfer in water where you wanted ALL the turbulence you can get.  My experiments showed that I was removing more heat than before but whether I would gain more or less with more turbulence is a ???.  I did add turbulators too, which improved heat transfer even more so I was still moving in the right direction when I stopped messing around.
If I could get springs or spirals made out of square stock, they would provide much more contact area and would really improve heat transfer.  Hmmmmm.  Anyone have a spring making machine and some aluminum square stock?????  You could sell a bunch of springs to people here and maybe even Quad.


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## Themlruts (Jan 8, 2014)

*tjnamtiw*
I see you have done some mods to your castile. I just picked up a castile this year since i bought a new house. In the old house I had classic bay 1200 and man could that put out some heat. Heated my entire 2000sqft split level.
My wife want to get the castile because of looks. I did know that it put out less BTU. But our house is now a small 1200 sqft ranch. I am just not happy with performance of the stove.
I see a lot of people do the air wash mod. But how do you do it? Do I buy different gaskets? 3 sides of my door have gasket but the bottom doesn't .
What about the springs? I have 10 tubes in my stove. I see people say they have ordered them but what size and where? Link?
Snap disk mod - Can you do it with the existing snap ring or do you have to buy the variable one?
Let me know what else i can do to increase efficiency. 
Thanks
Mike
PS I think we should make a sticky with all this info instead of having to fish through the whole thread


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## tjnamtiw (Jan 8, 2014)

Themiruts, all the info is right in this very long post plus use the search tool to look for other threads that speak of 'springs' and 'Quads'.  Also, look for threads by a fellow experimenter 'B-Mod' who is the 'author' of the constant blower speed.
Don't mess with your gasketing around the door.  You have the latest version.  That Castile should be able to heat your 1200 sq ft.  Make sure you have the flame height set per the instructions by adjusting the feed gate while on HIGH heat.


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## rcc (Jan 14, 2014)

tjnamtiw said, "That IS interesting, Andy. The next time the stoves are down for cleaning or warm weather, I'll pull a couple of the springs and take my inspection camera and feed it in the tubes to see if there is any evidence of corrosion. I would think after a couple of years that, if it's happening, I would see a spiral pattern of corrosion. Thanks for the warning. I'll feed back for the others who have made this mod. Worst cast would be to give the springs a 1/4 turn to put the contact at a different spot on the tubes."

tjnamtiw ......

Have you checked for corrosion in the tubes? I've got my springs cut to length and ready to install

Thanks.....


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## B-Mod (Jan 14, 2014)

I looked in mine, and the springs have been in for years (check the start of this thread), no corrosion. They were dusty, so I cleaned them, put them back in....


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## tjnamtiw (Jan 14, 2014)

rcc said:


> tjnamtiw said, "That IS interesting, Andy. The next time the stoves are down for cleaning or warm weather, I'll pull a couple of the springs and take my inspection camera and feed it in the tubes to see if there is any evidence of corrosion. I would think after a couple of years that, if it's happening, I would see a spiral pattern of corrosion. Thanks for the warning. I'll feed back for the others who have made this mod. Worst cast would be to give the springs a 1/4 turn to put the contact at a different spot on the tubes."
> 
> tjnamtiw ......
> 
> ...


Just now checked and I, like B-Mod, see no signs of corrosion.  Plenty of spider webs and 'future food', though.  Spiders were really bad this year.


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## rcc (Jan 14, 2014)

tjnamtiw said:


> Just now checked and I, like B-Mod, see no signs of corrosion.  Plenty of spider webs and 'future food', though.  Spiders were really bad this year.



Excellent


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## B-Mod (Jan 14, 2014)

tjnamtiw said:


> Just now checked and I, like B-Mod, see no signs of corrosion.  Plenty of spider webs and 'future food', though.  Spiders were really bad this year.


How do they like the heat?


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## Themlruts (Oct 19, 2014)

It starting the heating season here in CT i have my springs on order.  I will keep you posted


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## Themlruts (Oct 22, 2014)

I got my springs in i cut them to 9.  My question is do you let them fall all the way down?  They seem to really cut the airflow down.


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## Themlruts (Oct 22, 2014)

chickenman said:


> I havent read through the thread so maybe I have already made this suggestion;
> WE took a Santa Fe and slowed down the combustion fans as we thought the flue temp wastage was too high.
> THis transforms the Santa Fe as the heat exchange tubes absorb more heat.  It does make the stove body warmer but not to the point it is alarming.  Works perfect as the standard combustion airflow is insanely high.


How did you make that change.  I thought the mod was to keep the combustion fan on High while on medium?


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## SwineFlue (Oct 22, 2014)

Themlruts said:


> How did you make that change.  I thought the mod was to keep the combustion fan on High while on medium?



Two different quad mods here:   chickenman reduced the speed of the *combustion *blower, while tjnamtiw runs his *convection *blower on High.  

From chickenman's description of warmer stove temperatures,  I suspect these two mods (three mods with the springs) would work very well together.


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## tjnamtiw (Oct 22, 2014)

Themlruts said:


> I got my springs in i cut them to 9.  My question is do you let them fall all the way down?  They seem to really cut the airflow down.



The springs SHOULD be a tight fit!  The only way we got ours in was to twist them as we inserted them to reduce the diameter a little.  If yours are falling down, then either your springs are too small or they changed the ID of the tubes!  As for reducing airflow, you can see in one of my posts how much the airflow was reduced which, combined with more surface area gave time for more heat transfer.  Yes, we run our circulating fans on high all the time to get more turbulent flow.  Don't judge the air flow as 'really cut down' by feeling a particular tube as you will see some are reduced while others actually increase IIRC.  Been a while.


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## tjnamtiw (Oct 23, 2014)

chickenman said:


> THis offers the best possible heat exchange regardless of the fire.  THe noise drives me nuts though!!
> I actually put a trim pot. on the convection fan to slow it too.  Yes it does cut the efficiency a tad but atleast I dont get a headache from the noise.
> Wouldn't putting springs in the tubes make extra wind noise?


My fans are not that bad at all as far as noise goes.  I noticed no change in noise level with the springs.


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## Harvey Schneider (Oct 23, 2014)

tjnamtiw said:


> combined with more surface area gave time for more heat transfer.



I had some experience with using a twisted flat plate  to improve heat transfer from a flowing gas to a heat exchanger. The twisted plate was not well coupled to the heat exchanger, but was very effective in improving heat transfer.
It is hard to get good heat transfer from a round coil spring in contact with a cylindrical surface. The contact between the two is basically a line where the curvature of the spring touches the cylinder, not a surface.
In all likelyhood the improvement in heat transfer is caused by the turbulence introduced by the springs.
If I am right about that, it is not necessary to have a tight fit of the spring in the cylinder. A spiral twisted piece of sheet metal placed in the cylinder should do the same thing.
The turbulence caused by any object in the gas flow will cause some back pressure and will reduce flow. So even though you are running the blower at full speed you have, in fact, reduced it's output.


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## tjnamtiw (Oct 23, 2014)

Harvey Schneider said:


> I had some experience with using a twisted flat plate  to improve heat transfer from a flowing gas to a heat exchanger. The twisted plate was not well coupled to the heat exchanger, but was very effective in improving heat transfer.
> It is hard to get good heat transfer from a round coil spring in contact with a cylindrical surface. The contact between the two is basically a line where the curvature of the spring touches the cylinder, not a surface.
> In all likelyhood the improvement in heat transfer is caused by the turbulence introduced by the springs.
> If I am right about that, it is not necessary to have a tight fit of the spring in the cylinder. A spiral twisted piece of sheet metal placed in the cylinder should do the same thing.
> The turbulence caused by any object in the gas flow will cause some back pressure and will reduce flow. So even though you are running the blower at full speed you have, in fact, reduced it's output.


This is true.  The main reasons for the high speed blower and the springs IS to cause turbulence and prevent laminar flow in the otherwise smooth tubes.  Yes, there is not a lot of surface contact between the springs and the tubes but THERE IS SOME and every little bit counts.  Oh, and don't forget I also have 'turbulators' in the middle of the springs for even more help.  You can't knock success and all my measurements prove success.  

Themiruts maybe just needs to figure a way to 'suspend' the springs such as a tab on their ends or a bar across the end.


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## Harvey Schneider (Oct 23, 2014)

tjnamtiw said:


> You can't knock success and all my measurements prove success.


I wasn't knocking it, I was trying to explore understanding of what is going on in the heat exchanger. 
I'm not suggesting that you undo what you have, but I am curious if you have tried just turbulators and if the results were similar. The turbulators are cheaper and easier to fabricate.


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## tjnamtiw (Oct 23, 2014)

Harvey Schneider said:


> I wasn't knocking it, I was trying to explore understanding of what is going on in the heat exchanger.
> I'm not suggesting that you undo what you have, but I am curious if you have tried just turbulators and if the results were similar. The turbulators are cheaper and easier to fabricate.


No problem, Harvey.  You know, I don't remember if I just tried the turbulators.  They came from a fellow burner whose name escapes me right now (sorry).  They certainly have been proven effective in industrial and military applications but these are pretty small in comparison to the diameter of the tubes.


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## Themlruts (Oct 24, 2014)

tjnamtiw said:


> This is true.  The main reasons for the high speed blower and the springs IS to cause turbulence and prevent laminar flow in the otherwise smooth tubes.  Yes, there is not a lot of surface contact between the springs and the tubes but THERE IS SOME and every little bit counts.  Oh, and don't forget I also have 'turbulators' in the middle of the springs for even more help.  You can't knock success and all my measurements prove success.
> 
> Themiruts maybe just needs to figure a way to 'suspend' the springs such as a tab on their ends or a bar across the end.


I may just try to to widen one end.  That should do it.


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## tjnamtiw (Oct 24, 2014)

Themlruts said:


> I may just try to to widen one end.  That should do it.


Yea, you could just spring one end open so it would not fit down in.  Good idea.  I still think that there is enough contact to transfer heat, though, but what do I know, I'm just a 'dumb Dutchman'.


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## Themlruts (Oct 24, 2014)

K so not to sound like an idiot but i'm looking at b-mod mod.  
1. Convection blower is what blows the air into room
2. Combustion blower is what feeds air to the fire.  Is this also the exhaust blower?
If I understand his mod correctly is that the convection blower will always be set to hi even when you switch it to medium?
Will I have to change my feed rate if i put it on medium?


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## tjnamtiw (Oct 24, 2014)

The combustion blower and the exhaust blower are the same thing.  Just two terms for the same blower.

When you put it on medium, you ARE changing your feed rate and the combustion blower speed.  Only the convection blower remains on high.  You don't need to adjust the feed gate except when you change pellet lots or you see a change in pellet length from the last bag.  Always adjust that on HIGH, but in most cases you will only do this a few times a season unless you are looking for something to play with.


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## B-Mod (Nov 1, 2014)

B-Mod? Did some one ring? Lol, 12 degrees here this AM, snowed yesterday, the heating season is on. Hauling corn in today!


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## tjnamtiw (Nov 1, 2014)

Hi BMod.  24 here tonight in sunny Georgia!  You can keep that 12 degree crap!


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