# Wood boiler not enough?



## cschwinn (Mar 28, 2011)

I just finished a new heating system and went with a New Yorker 130 wood boiler with a wall-mount propane boiler as a secondary boiler.  I run both Radient heat and baseboard off this set-up as I have existing structure and a new addition.  My problem is that the wood boiler gets the water in the boiler up to temperature and then dumps it into the heating loop, and within a minute or two, the returning water from the house cools the boiler down and then starts the cycle of the boiler needing to get the returning 20 gallons of water back up to temperature.  This can take 7-9 minutes based on the fire.  By that time, the hot water that is circulating in the house is cold again.  When sizing my system, the heating contractor said I needed 80,000 BTU's, and we went with a 130 to allow for overage.  Therefore, it doesn't appear that I am undersized.  The propane works well, but it uses propane which is my problem there!  I would like to have a heating system that doesn't burn so much propane through the winter months.  I was hoping this wood boiler would be able to stand alone 80-90% of the time, but it is just not doing it.  I thought about even getting a different boiler such as a gasification boiler or coal that may be able to have a shorter recoup time.  I could really use some help here as I have had my heating guy and a field rep from the distributor come and look at my system.  The end result is both of them shaking their heads and walking away with no great ideas.  Thoughts?  Ideas?


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## Willman (Mar 28, 2011)

Hows you wood supply? Good species and MC?
Are you running return temperature protection? Primary combustion boilers don't get as hot as gassifiers, but you should be able to make it work. Others will chime in with their suggestions.

Will


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## Hunderliggur (Mar 28, 2011)

If you have a return protection loop (I use a 140F Danfoss Valve), the boiler will work up to a steady state.  My gassification boiler runs about a 20F delta T while charging a storage tank.  You don't have storage, but the idea is the same.  When the boiler is starting up and the house (or heating loop) is warming up, you will have a lower flow rate to the house as the return temp builds.  As the return temp builds, the flow to the house will be greater.  A wood boiler s not an "instant on" device like a propane (or electric) boiler, but it can be less expensive to operate.  You could use the boiler to "pre heat" the propane.  Until theboiler reaches a good steady stat, the propane will add heat to make up to the usable temp.  THis will get the return temps up quicker and then the propane will not have to fire.

Hope this helps.


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## cschwinn (Mar 28, 2011)

Interesting, I have been trying to find ways to slow down the returning water - possibly through Actuators in my Radiant loop manifold etc. This looks like a viable and less complicated alternative. One question I have is where it should be located. I have a bypass valve (manual valve) that I placed in the line right above the boiler with it staying at 1/4 open. This keeps the returning water from what I have termed "tanking" the boiler where the return temp drops the boiler temp 20+ degrees. Then it takes a day's age to recover. It helps slightly, but still is nowhere near what I need. This valve looks like this may be another good option and would probably solve or reduce my creosote issue - which can be substantial.

Placement is a question. I have so much water in the system, it takes so long for the boiler to affect the return water temp from the radiant (and to a lesser degree of the baseboard) - if at all. I could see my boiler running for hours before it is going full speed to the heating loops. I assume I would want it on the return line as in the attached diagram recommended by the manufacturer as close to the other loop as possible?


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## NYEDGE (Mar 28, 2011)

I agree that a Danfoss valve would help tremendously.
It should go at the return of the boiler in order to mix the water to 140 deg and therefore the water in the boiler will remain more consistent in temperature.


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## Fred61 (Mar 28, 2011)

NE Wonder said:
			
		

> Interesting, I have been trying to find ways to slow down the returning water - possibly through Actuators in my Radiant loop manifold etc. This looks like a viable and less complicated alternative. One question I have is where it should be located. I have a bypass valve (manual valve) that I placed in the line right above the boiler with it staying at 1/4 open. This keeps the returning water from what I have termed "tanking" the boiler where the return temp drops the boiler temp 20+ degrees. Then it takes a day's age to recover. It helps slightly, but still is nowhere near what I need. This valve looks like this may be another good option and would probably solve or reduce my creosote issue - which can be substantial.
> 
> Placement is a question. I have so much water in the system, it takes so long for the boiler to affect the return water temp from the radiant (and to a lesser degree of the baseboard) - if at all. I could see my boiler running for hours before it is going full speed to the heating loops. I assume I would want it on the return line as in the attached diagram recommended by the manufacturer as close to the other loop as possible?



I know nothing about the make of your boiler and how it burns but what you say is that you have a boiler firing flat out and not keeping up with demand yet you are saying you have a creosote issue. I will side with Willman and suspect you may have a moisture content issue with your wood.


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## cschwinn (Mar 28, 2011)

I burn Maple and White Birch - pretty much the staples around here which has cured under a lean-to for a year.  I don't doubt that it could be dryer, but it also seems that when the boiler returns such cold water it appears that there is condensation that occurs.  I notice this especially when I am not running the baseboard from the boiler and therefore turn down the set-point to accomodate just the radiant.  Then the return water may get below 120-130.  Earlier in the winter I turned the set-point up to 170-180 to accomodate the heating demands and the creosote was not as significant.  I appreciate the feedback as I continue to learn more about this system every day, and everything helps!  I also am happy to say that I finally got a year ahead on my wood pile for next winter which has been curing since last summer.


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## Kawliga (Mar 28, 2011)

NE Wonder....

Couple of questions...what is your boiler capaity? Do you know the fluid capacity of your radiant and baseboards? What temp does your boiler get up to...you should only need 110 to 120 degree water in your radiant loops? 

I had same issue with my Benjamin oil/wood combo...40 gallon capaity in boiler, 80 gallons in my radiant loops....when burning wood, my Benjamin could not keep up, but as another member noted, wood is nowhere near as fast as oil/gas/propane....so it take a while to get that water up to temp....and because of the cooler return water, it never will. If I used the oil part of my boiler it could keep up, barely, but it really sucked back the oil. The Danfoss will help as it will limit the cooler retrun temp water from cooling down the boiler....but IMO, sorry to say, will not fully solve your problem...depends quite a bit on what the temps are going out, and what the return temps are....if there is too much of a Delta, the Danfoss will just be recirculating to the boiler, and not to the emitters...

I think some form of well insulater storage is in order to bring up your capacity, in addition to the Danfoss....

I ended up switching to a CB 6048 which has almost 400 gallon capacity....I dont use the Benjamin anymore....

BTW, I do not think you have a wood issue or moisture issue IMO

Good Luck

Mike


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## willworkforwood (Mar 28, 2011)

NE Wonder said:
			
		

> ...  but it also seems that when the boiler returns such cold water it appears that there is condensation that occurs.  I notice this especially when I am not running the baseboard from the boiler and therefore turn down the set-point to accomodate just the radiant.  Then the return water may get below 120-130.  Earlier in the winter I turned the set-point up to 170-180 to accomodate the heating demands and the creosote was not as significant. ....


It sounds like you have 2 problems with your system.  As others have said, the 140+ return protection is mandatory.   Is there a near boiler return loop piped in, and just doesn't have a mixing valve?  Or, is there no near boiler return loop at all?  You mentioned a "heating guy" and a field rep.  Did they do the install?  In any case, you need to get that fixed ASAP, because your boiler is probably already starting to rust away.  
But beyond that big problem, it sounds like you might be trying to run your boiler with a combination of a big fire and too low of a set point.  If you run even close to a full firebox of wood, and a boiler water temp of less than 170, you would have nothing but a smouldering fire.  This would also explain the large amount of creosote that you describe (regardless if the wood is seasoned or not).  How much wood are you loading - do you always have a big fire going?  It's very hard to keep a good sized wood boiler under 170 (or even 180).  I do it occasionally, but never with anything other than a very small fire (i.e. 3-6 small splits).  Best of luck getting your boiler problems resolved soon.


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## cschwinn (Mar 28, 2011)

Kawliga, sounds like your earlier situation was similar to mine.  Basically what I have figured is that the boiler gets 20 gal (in the water jacket) up to temperature, then dumps it into the heating loop.  The return water drops the temperature 10 or so degrees and the circulator to the boiler stops (the heating loop keep circulating the previously heated water) and the fan kicks in to amp up the temperature and therefore bring the next 20 gallons up to temperature.  This process takes roughly 5-7 minutes until the boiler turns those 20 gallons loose into the system.   In the meantime, the previously heated water has cooled down to room temperature and therefore sends back colder water to the boiler where the circulator stops and the above cycle starts all over again.  After more thought, the Danfoss Valve would help if the set-point is close to the 140 degrees so it doesn't take so long to cycle, but once opening up to the heating loop, it would take presumibly hours for the heating loop to gain in temperature enough so the hot water will circulate all throughout and then return to the boiler.  I go back to the idea of acctuators that I had to basically make my 12 loop manifold (200 ft. per loop) break down into three zones which would reduce the demand on all that water coming back at once.  Right now, if I turn all but three loops off on my manifold, and only allow those three to circulate, the return temperature starts rising within 10-15 minutes or so.  Something that would never happen if I ran all 12 loops at the same time even if the boiler ran all night - it may rise 5-10 degrees on the return manifold.  My thoughts were if I only allowed a few loops to circulate at a time, I would reduce the volume of return water.

Now, when I run the propane, it works well!  Heat, comfortable, even warmth.  The reason is that the Propane is constantly applying heat and can keep up with the return water.  With the propane, the entire 12 loops on the radiant manifold jumps 15 degrees within the first 10 minutes.

Willworkforwood, I usually run the water temperature at 180 degrees (mixing valves on the Radiant bring it down to 120 on the Radiant loops) to account for the baseboard.  I tested it on a lower set-point and that was what I found out.  As mentioned above the circulator stops bringing back return water once I lose 10 degress on the set-point.  So, I can keep the water in the boiler above 140 degrees, it's just that the remainder of the water in the system cools down while the boiler is cycling.

I am in the process of finding out the fluid capacity of the boiler, I have a call into the company as I can't find it online.


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## Kawliga (Mar 28, 2011)

yup, sure sounds similar....we struggled with the Benjamin for 5 years....we didn't install actuators, but put in programmable tstats. We have 7 zones, all with a tstat and all with their own circulator. Set these so that no more than  2 or 3 zones would come on at a time and set them up to rotate.

The tstats, in combination with very hot fires saw us thru those 5 years but a huge PIA....we managed to keep the house reasonably comfortable, (nowhere near what my wife and family prefer but comfortable). It was high maintenance heating, albeit we didnt use hardly any oil the last 4 years, just when we went away. That said, the amount of time spent stoking the fire to keep it running real hot, (stack temps between 400 and 500 F), extra dry good quality hardwoods, (only maple and red oak), and the amount of cleaning required, (because we had to run the boiler as hot as we could, somewhat incomplete combustion means lots of coals), we had to clean out the boiler every 2 to 3 days....messy dirty job....the Benjamin is dutch overn type, round firebox....

Nowhere near what I would call ideal setup or efficient....but it worked....as I noted this year we had finally had enough and switched to the CB 6048 OWB...it literally has changed our lives during the heating season....for the better of course...no longer do we separate our zones, all the tstats are set to what we want when we want and the OWB keeps up with no issue....also house is a ton warmer than before....and you just have to love 12 to 24 or more hour burn times...especially when we were used to 2 or 3 hour burn time in the past....this year we wonder how we ever found the time to keep up....and now enjoy our extra spare time getting wood and doing other things that dnt eveolve around being a slave to your boiler...

Hope you can find a resolution....thinking some form of storage....and also you may want to consider some additional expert help...sorta sounds like your installer and his assistant arent going to be much help...
Mike


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## Singed Eyebrows (Mar 28, 2011)

NE Wonder said:
			
		

> I just finished a new heating system and went with a New Yorker 130 wood boiler with a wall-mount propane boiler as a secondary boiler.  I run both Radient heat and baseboard off this set-up as I have existing structure and a new addition.  My problem is that the wood boiler gets the water in the boiler up to temperature and then dumps it into the heating loop, and within a minute or two, the returning water from the house cools the boiler down and then starts the cycle of the boiler needing to get the returning 20 gallons of water back up to temperature.  This can take 7-9 minutes based on the fire.  By that time, the hot water that is circulating in the house is cold again.  When sizing my system, the heating contractor said I needed 80,000 BTU's, and we went with a 130 to allow for overage.  Therefore, it doesn't appear that I am undersized.  The propane works well, but it uses propane which is my problem there!  I would like to have a heating system that doesn't burn so much propane through the winter months.  I was hoping this wood boiler would be able to stand alone 80-90% of the time, but it is just not doing it.  I thought about even getting a different boiler such as a gasification boiler or coal that may be able to have a shorter recoup time.  I could really use some help here as I have had my heating guy and a field rep from the distributor come and look at my system.  The end result is both of them shaking their heads and walking away with no great ideas.  Thoughts?  Ideas?


It sounds like you might have a draft issue if your wood is dry enough. With dry wood & good draft you should get some decent heat out of that even though it isn't a gasser, Randy


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## Paver56 (Mar 29, 2011)

I feel your pain.  I too have a New Yorker WC 130.  My experience is that burning coal works great if you can tend it every 3 or 4 hours.  I put fire brick around the inside, replacing the steel that comes with it.  That allows me to have a deeper bed of coal.  The last 2 months I have been burning only wood.  I have over 7000 ft of pex in my house.  The wood burns good too but I still have to tend it every couple of hours.  I also have a creosote problem.  
Personally, I would not wish this boiler on my worst enemy unless they wanted to get very little sleep or deal with a cold house every morning.  I have not paid for the wc130 yet.  I know the guy that put it in for me and he knows that it is not getting sufficient burn times.  I have even talked to the factory and they told me that they aren't designed to get for than 4-6hrs of burn time.
I hope that you are able to work out your issues.  I am returning mine this summer and installing eithe a Froling or an Effecta with storage.  I am really looking forward to being able to sleep through the night next season.


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## Paver56 (Mar 29, 2011)

I forgot to mention that I have all radiant and that burning with coal seems to regulate the temp a lot better.  I also have a wall mounted condensing propane boiler.  
These boilers are a big investment and if you cannot get your problems solved, I would try to get them to return the boiler.  The thing that upset me the most is that they told me that I should not expect to get an overnight burn.  I told them that there literature is quite misleading if that is the case.  The factory guy I spoke to said that it is designed as and add on boiler and not meant to be the sole heat source.


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## cschwinn (Mar 29, 2011)

Ben, thanks for the reply, although feeling more disheartened about my ability to get this thing to work, it seems like I am facing reality.  I have 2400 ft. of pex radiant and 50 feet of baseboard.  I haven't turned on the basement radiant because the system can't sustain the living areas.  The wall-mounted condensing propane keeps the place comfortable, the wood on it's own doesn't.  It can't keep up with the baseboard by itself all night (not counting the radiant).  I called the rep. yesterday from New Yorker to figure out the "water capacity" answer as posted above.  Needless to say he didn't let me get a word in edgewise to explain my problem.  He was quick to say that the boiler is not a sole heat source and interrupted me when I explained how it would not handle the load.  Then he said the water in my system is "nothing" for the boiler and that it can handle it easily.  Yet I am confused if it can handle it "easily", why it can't work on it's own.  To me he sounded quite defensive and was looking for any opportunity to say it wasn't the boiler's issue.  I never placed the problem there with him, I was trying to figure out how I can best set-up this system.  Wonder how many of these calls he gets.

I'm toying around with the idea of storage, do you have any?  Thought that might help with the cycling issue as it can take 7-9 minutes to cycle another batch of hot water.  Can't figure it out, a friend has the same boiler and he gets 10 hour burn time and warm/cozy house running this as his primary during cold weather.  Just my luck...


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## willworkforwood (Mar 29, 2011)

Has this system been fully purged of air (all loops and both boilers)?


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## heaterman (Mar 29, 2011)

A couple comments...........

Any wood boiler needs to be maintained at 150* water temp or higher. Running below that point gets you into the condensation area and as you have discovered, that is not a happy situation.

As others have said, a solid fuel boiler is not an instant on appliance like a gas or oil fired boiler would be. It takes a while to get the fire ramped up to full output, especially when it's trying to meet the building load as well as warm itself up. When the boiler is sized closely to the required heat output, it can be a real struggle.

BTU storage of some type would really help your situation along with some kind of boiler protection mixing device. Either a Termovar type valve or an injection mixing circ set up to protect the boiler would help your situation out immensely.

If you have a high mass radiant slab, it is nearly mandatory to have some kind of storage to cope with the huge btu load dumped on the system when it calls for heat. Can it be done other ways? Yes, but you'll find that a healthy amount (minimum of 300-500 gallons of water stored at 180* or so is far simpler than trying to out engineer what is happening in your system. 

A stop gap measure you might consider would be to run your boiler at 180 all the time and use a mixing valve to drop the temp to your radiant floor rather than lowering the boiler temp. That would be far better for the boiler than trying to make it do something it is not designed to do. Namely, running at <150*.


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## cschwinn (Mar 29, 2011)

Yes, I isolated each loop to make sure and have an airscoop on the system that seems to work well.


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## cschwinn (Mar 29, 2011)

heaterman said:
			
		

> A couple comments...........
> 
> Any wood boiler needs to be maintained at 150* water temp or higher. Running below that point gets you into the condensation area and as you have discovered, that is not a happy situation.
> 
> ...



heaterman, I think you summed up the two options I have available to me.  The boiler protection mixing device may help, although I still wonder if I can see the difference in anything less than a few hours of run time given how slow it takes for my return water to warm.  Nevertheless, it theoretically should help.  As for the storage, that makes some sense as well, given the high mass I have in the radiant (gypcrete overpour) which again the return water takes forever to warm up.  I already have the stop gap measure in place and have mixing valves on the radiant loop and run my radiant at 120.  As mentioned before, I run the boiler at 170-180 unless I am "testing" a brainstorm.  What amazes me is that I roughly calculated that I probably have around 35 - 40 gallons of water in the system (not counting the 21 in the boiler).  This doesn't seem like a whole lot, and therefore makes me wonder if the storage will make a huge difference.


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## heaterman (Mar 29, 2011)

NE Wonder said:
			
		

> heaterman said:
> 
> 
> 
> ...



RE: storage

A radiant floor will pull all the "heat" out of 60 or so gallons of water in one round trip more or less. If you are working from storage you basically have a larger flywheel to counteract the flywheel in your floor. Without that, it comes down to nothing more than raw horsepower needed to meet the load as well as keep the boiler up to temp. 300 gallons of storage for example with a 30* drop 180-150 will provide roughly 80,000 btu's of heat to your floor unassisted by the boiler. This allows time for the fire to get rolling before having to actually meet the load head on. There are only two ways to fight a high mass "radiator" like your floor. Raw horsepower or with an equal amount of mass.


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## Paver56 (Mar 30, 2011)

NE Wonder-  I do not have storage.  I am going to install storage with my new gassifier (when I get it)  I too have thought of adding storage and I think that it would help but I came to the realization that a gasser would be much more efficient.  Burning coal in my wc130 makes a ton of heat.  The problem is that getting a good coal fire going takes at least an hour.  I would much rather be able to light a fire in a couple of minutes and walk away.  The other problem with coal is the amount of ash and this boiler seems prone to a lot of clinkers.  I figure if I am going to spend money on a boiler, I want it to be something I enjoy and look forward to lighting, not something I dread dealing with.  If you don't mind me asking, how much did you pay for the wc130?


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## heaterman (Mar 30, 2011)

Want storage? Want to light a fire and walk away? Want a boiler that is nearly impervious to low return temperature? Get a Garn. My 11 year old grand daughter can load theirs when dad is not around.


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## cschwinn (Apr 10, 2011)

I am working on storage ideas, can anyone direct me to some good DIY plans?  I have access to a 320 gallon propane tank that should cost next to nothing.  Seems like that is a preferred method from what I read on here.  Problem is it is 20 inches to tall to stand on end, which seems to be critical for stratification.  Contemplating blocking it up on an angle (possibly welding legs), but not a big fan of the idea.  Just trying to work with this cheap, hard to find tank.  Really not interested in spending another $1,000+ on storage.  Any thoughts or direction would be helpful!  Seems like 300 gallons is as low as I would like to go, need 80,000 BTU's per the "sizing" formula.


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## ewdudley (Apr 10, 2011)

NE Wonder said:
			
		

> I am working on storage ideas, can anyone direct me to some good DIY plans?  I have access to a 320 gallon propane tank that should cost next to nothing.  Seems like that is a preferred method from what I read on here.  Problem is it is 20 inches to tall to stand on end, which seems to be critical for stratification.  Contemplating blocking it up on an angle (possibly welding legs), but not a big fan of the idea.  Just trying to work with this cheap, hard to find tank.  Really not interested in spending another $1,000+ on storage.  Any thoughts or direction would be helpful!  Seems like 300 gallons is as low as I would like to go, need 80,000 BTU's per the "sizing" formula.



Vertical happened to be doable in my situation, but from from reading here and by the nature of the problem it's clear that horizontal tanks work quite well.  

The only trick is in avoiding vertical jets of water entering the tank when charging the top of the tank or when returning spent water to the bottom.  Some guys have had horizontal pipes welded in at the top and bottom of the horizontal tanks, others have  used simple diffusers in the existing ports, and others still just use fat pipes with the existing ports and find there's no big problem.

Plus if you're really feeding an 80,000 btu per hour load a 320 gallon tank would be more of a buffer tank than a storage tank and stratification wouldn't be such a big deal to begin with.  Definitely worth doing though, it would help insure than when the boiler is running it can run flat-out hot and clean for an hour or two at a time.

--ewd


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## Willman (Apr 10, 2011)

> Problem is it is 20 inches to tall



Is there a possibility of excavating a couple of feet for clearance ? Pour a new pad and allow space for insulation piping etc. Same gallons as horizontal but less of a footprint.

Will


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## cschwinn (Apr 10, 2011)

ewdudley said:
			
		

> Plus if you're really feeding an 80,000 btu per hour load a 320 gallon tank would be more of a buffer tank than a storage tank and stratification wouldn't be such a big deal to begin with.  Definitely worth doing though, it would help insure than when the boiler is running it can run flat-out hot and clean for an hour or two at a time.
> 
> --ewd



Is there a formula somewhere that would allow me to know what to expect from a 320 gallon tank?  I am concerned that I would go through all this work and still find that my reserve is not big enough.  The boiler struggles to keep up at full speed and I want to avoid that if possible.


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## cschwinn (Apr 10, 2011)

Willman said:
			
		

> > Problem is it is 20 inches to tall
> 
> 
> 
> ...



Nope, tubing in the floor.  Unfortunately not an option...


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## ewdudley (Apr 10, 2011)

NE Wonder said:
			
		

> Is there a formula somewhere that would allow me to know what to expect from a 320 gallon tank?  I am concerned that I would go through all this work and still find that my reserve is not big enough.  .


These might show up in Those Useful Tidbits but here they are:  A btu is the energy to heat one pound of water one degF, and a gallon of water weighs as close as you please to 8.333 pounds per gallon.

One thing these imply is that gallons per minute (gpm) times deltaT degF times five hundred equals btu per hour.  For instance if you had 3 gpm going to a section of baseboard and it goes out at 175 degF and it comes back at 150 degF, then btu per hour would be 3 * (175 - 150) * 500 = 3 * 25 * 500 = 37500 btu / hour.

And back to your storage tank: 320 gallons is 2667 lbs of water, so that's 2667 btus per degF of deltaT that you can store in the tank.  If you can go from 185 degF down to 135 degF that's 50 degF deltaT, or 50 * 2667 = 133000 btu, give or take.

You say your head load is 80000 btu per hour, so that's an hour and forty minutes of storage flat-out at 80000 btu per hour.

Which sounds discouraging.  But is your heat load really 80000 btu per hour? If you ever heated the system with fossil fuels exclusively you may be able to go back and figure a good estimate of the amount of fuel you were using in the middle three months of winter and use that to figure average heat load.  If your load is actually more like 35000 btu per hour, now you've got close to four hours of storage.

Also since you have a mix of baseboard and radiant, you can feed the baseboard first and then mix the baseboard return water down for the radiant loads and perhaps get you storage return temperature down below 100 degF.  This increases your storage deltaT (in the what-if example) from 50 degF to 85 degF, which gives you about 225000 btu storage, or about 6.5 hours storage at 35000 btu per hour (assuming your real heat load is as low as 35000 btu per hour).

But in any event 320 gallons is plenty to at least help solve a creosote problem caused by short-cycling of your current boiler.  The unit would be able to run hot and clean at full load for an hour or more and then could shut its draft off completely for a good while and then run at full load again when the tank is depleted.  This avoids having so many smokey start-ups and periods of smoldering limited draft.



> The boiler struggles to keep up at full speed and I want to avoid that if possible.


As others have suggested above, the fact that your boiler can't keep up without storage doesn't sound right.  If the fuel is going in the fire box and the ashes are coming out, then there are a few things to look at. 

First is inefficient burning with smoke going out the stack.  Storage may help this by allowing you to tune the unit burn correctly at the rate you choose to burn at.

Second would be excess combustion air, meaning you're burning clean but you're mixing in a lot of extra air that is cooling your exhaust gases and limiting the amount of heat you can extract from the mixture.

Third would be too much fire relative to your exhaust-to-water heat exchange surfaces.  This would mean high flue temperatures with heat going up the flue before it has a chance to heat your water.  You would need to limit the rate of burn and tune it to run clean to solve this problem.

--ewd


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## cschwinn (Apr 11, 2011)

As others have suggested above, the fact that your boiler can't keep up without storage doesn't sound right.  If the fuel is going in the fire box and the ashes are coming out, then there are a few things to look at. 

First is inefficient burning with smoke going out the stack.  Storage may help this by allowing you to tune the unit burn correctly at the rate you choose to burn at.

Second would be excess combustion air, meaning you're burning clean but you're mixing in a lot of extra air that is cooling your exhaust gases and limiting the amount of heat you can extract from the mixture.

Third would be too much fire relative to your exhaust-to-water heat exchange surfaces.  This would mean high flue temperatures with heat going up the flue before it has a chance to heat your water.  You would need to limit the rate of burn and tune it to run clean to solve this problem.

--ewd[/quote]

Thanks for the feedback, your three suggestions above sound reasonable, I just don't know how to go about testing/ruling them out.  I will have to think about that.  As far as I can tell, the recovery time for the boiler (7-9 minutes) is to long that the previous charge of hot water has already cooled down to room temperature.  I'm hoping that a steady load of hot water can avoid this happening.  The well insulated storage tank should help in holding that steady charge and allow the boiler to help the storage recover 20 gallons at a time.  Hopefully I'm not missing something with this plan!


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## cschwinn (May 25, 2011)

In fairness to the boiler manufacturer and for feedback to all of your great thoughts/assistance with my issue, I wanted to post an update.  I talked with a local rep who supports the boiler, and found someone that can be helpful!  Anyway, after sending pictures he noticed that the return piping came in the side of the boiler rather than in the back (allowing better water flow from the back across the firebox and out the supply).  I switched it and am noticing some benefit although have to wait until colder temps to really test it.  Seems like it was a worthwhile change as I am extending my run time already.  From my observations, even an extra 30 seconds to a minute will help tremendously.  Now onto the second step which is storage.  I am contemplating a DIY experience...considering fiberglass, propane tanks or some other structure.

Thanks again for the input!


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## Willman (May 25, 2011)

> considering fiberglass,



Tanks should be able to handle high temps. not certain if fiberglass can do that. I would go with the steel propane tanks.

Will


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## Singlemalt (May 26, 2011)

> I have 2400 ft. of pex radiant and 50 feet of baseboard.



Is this one loop? If not, how many loops do you have? and how long are they?

What size circulating pump are you using?


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## Urban Hillbilly (May 26, 2011)

I have had similar problems. The recomenations you are getting are probaly better than mine, but I found a simple fix. I have a Franco Belge wood boiler from the 70's tied into my natrual gas system. The wood and gas boiler use the same circulator signaled by the thermostat or a strap on aquastat on the wood boiler. I just added a second aquastat on a timer switch. This allows the wood boiler prime the whole system with a base line temperature. You will figure out how long this takes through trial and error. Once the timer switch turnes off the system should be primed, at which point the second aquastat circulates at a hotter temperature. Keep in mind, this is just what I had to do to get my old heap to heat the place.


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