# Quadrafire 1200i convection blower snap disc behavior



## Rainforest (Nov 14, 2009)

I'm posting first some info about how the Quadrafire Classic Bay 1200i works, and then asking for some advice.

We've been running the 1200i with a fairly low feed rate and heat output switch set to low. Fire looks nice, but we noticed it takes more than 30 minutes after fire ignite for the convection blower to come on. By this time, the unit seems crackling hot, so we wondered why the snap disc thinks it's not. We got out our handy temperature meter with thermocouple wire (we're scientist, so have such stuff lying around) and slightly unscrewed snap disc #1 to insert the thermocouple wire so it's touching the disc, retighten, and then we could measure the temperature at the snap disc location. (BTW - snap disc #1 and #2 are behind the LEFT side door, not the RIGHT side door as it says in the manual. At least they got the wire colors right, #1 has purple wires.)

Our thermocouple indicated that the snap disc #1 turns on the convention blower when the disc reaches about 125F, just like the manual says it should. So that means our sneaker thermocouple is making good thermal contact so we can know what's going on, and that indeed the snap disc is functioning as indicated on the tin. As I said, before the snap disc says its 125F, the nice fire has much of the insert crackling hot, but at the snap disc location it's staying cool. Indeed, we measured the temperature at the heat exchanger tubes at >300F while the snap disc location is still below 125F. It took more than 30 minutes of a nice fire for the snap disc to finally reach 125F. How silly is that? Behind the right side door where the electronics are, it feels much hotter to touch than it does behind the left side door where the snap discs are. Again, just how silly is that? We conclude we're using more pellets than necessary to heat the room because this convention blower is so slow to come on.

Next step (after unit cooled down) was to restart, but this time with the blower set on high. We did not change the feed rate. Once ignited in 2 minutes, we had a really blazing fire - it was scary big to our eyes. Just ten minutes after the fire ignited, our thermocouple and snap disc are at 125F and the convention blower comes on - blasting out almost unbearable heat. Prior to the convention fan coming on, the snap disc area was heating up fast - it only took about 3 minutes to go from 100 to 125F. But after the convention fan came on, the temperature in that area stablized and held around 127F. That's all good stuff. Except I don't really want to listen to the noise of all the fans running on high.

I'm currently waiting for the unit to cool, so I run the test again at Medium heat setting, but in the meantime, I thought I would post this info, as I see some older posting where people are thrashing with this same problem. They always seem to decide to run on high to get the convection fan to turn on faster (which our tests show definitely does work if you don't mind a scary blinding fire and lots of noisy fans).

I'm wondering about 2 possible alternatives:
1) Change to a fan control snap disc that turns on at 100F. Using our sneaker thermocouple, we decided that 100F at the left side would be a good temp for the convention blower to come on with the heat output on low. I've searched the internet for a replacement snap disc, but the only one that looks like the quadrafire snap disc is this one from Senasys being sold exclusively via Amazon.
http://www.amazon.com/Senasys-100Â°...ch/dp/B0026RYU4W/ref=pd_ts_hi_10?ie=UTF8&s=hi

The description says this is 3/4", which no matter how you measure it, seems lots bigger than the snap disc quadrafire are using. I tried sending the vendor an email asking for dimensions, but I guess for a <$10 part, no one was interested enough to respond.
So my question is - does anyone know where I can get a properly sized snap disc that closes at 100F?

2)OR - we thought maybe we could keep the 125F snap disc, but add a little copper braid (or some other material that transfers heat well) between a heat exchanger tube the the snap disc to allow the heat to get to the left area better. Like I said, there must be better thermal contact between the right side of unit than the left side where the snap discs are, because the right gets lots hotter than the left. And remember, my heat exchanger tubes are way over 300F while the snap disc area is still around 100F. If we could just get a little more heat flow to the left, then the snap disc would activate sooner.
So my question is - has anyone tried delivering more heat over to the left side where the snap discs are?

And finally, if there are any Quadrafire designers who reads this posting, could you please consider changing the position of your snap discs so they are in a better location to sense the insert temperature. That left side is just too chilly a location for the snap disc. Maybe you should have stuck with the right side where its hotter, which is where the manual says they are supposed to be located.

I guess that means a third alternative is for us to physically move the 125F snap disc over to the right side. We've not looked into that yet, so don't know how changing the wire locations would work out.

Of course, all 3 of my proposed mods are going to void my warranty, so I really wish Quadrafire would come out with an approved solution.


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## kilbury (Nov 14, 2009)

Quadrafire makes different temp snap disc to fit various stoves (gas-wood-pellet), of lower temps. I don't have part numbers on hand but can look them up when I get back to the shop. Or you can do a little leg work and check different owners manual on their website. I can't see any ill effects of replacing it with  a lower temp disc. Maybe in an extreme situation you could move too much heat out of the unit and the thermocouple would not sense the 200 and 600 degrees at the firepot. Good luck and let me know if you want those part #'s


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## CanadaClinker (Nov 14, 2009)

Hey Rainforest... welcome..... I have the free standing cb1200 and had similar observations as yourself.  My snap disc for the convection blower is at the right at the back of the exchanger.  I used a remote turkey thermometer to discover that the 'output' of my exchanger tubes reached 300 deg before the convection blower would come on.

It takes 2 minutes for the flame to catch hold from a dead start.  In another 2 minutes, the output of the exchanger tubes was 80 deg and above from a cold start.  I made a 4 minute timer (using a 555 timer)  that was triggered by the thermostat coming on.  After 4 min, a relay which is in parallel with snap disc 1 closes and starts the convection blower. 

By the time the thermostat says the room is warm enough and shuts off, snap disc 1 has already come on by itself and now holds the convection blower on till the exchanger cools down enough (which is around 93 degrees at the output of the exchanger).  

I was thinking the same as you..... that I was wasting heat ($$) by not getting it into my room as soon as it was available.  IMO, the snap disc #1 is located too far back on the exchanger (which is also lower, and we know heat rises to the front as the exchangers are on a slope up to the front).

Anyway, had fun experimenting and making the circuit.  I built it in such a way that it can be unplugged from the stove in a matter of minutes without altering the stove circuitry itself.  I would have moved snap disc 1 but stove is still under warranty and the bracket holding it is welded firmly to the rear of the exchanger.  ........cc  :cheese:


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## Rainforest (Nov 14, 2009)

Balls of Fire - thanks for the suggestion and offer to look up part numbers. I just spent some time doing that, and only found 1 snap disc for Quads that is less than 125F (it was 110F), but its not the right form factor from the pic. So I think that idea won't fly.

CanadaClinker - you just reposted my posting. Did you want to add a comment?

An update - I ran the stove on medium with same feed rate, and measured time & temp again. The stove was a little warm when I started, so test may be skewed. Anyway, again, it took only 10 minutes after ignition for convection blower to start. Once started, the snap disc temp stablized about 116F. When running on high, the snap disc temp stablized about 127F. So clearly high means hotter, which is obvious from the leaping scary flames on high. The Medium fire size was more reasonable, and fan noises are bearable, but I sure wish low was a feasible run setting. Why did they offer low if the unit works so poorly when set to low???


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## slls (Nov 14, 2009)

I run mine on medium with the thermostat. The stove going into start up mode. It runs that way which is high until the thermocouple reaches 600 F, it then goes to medium mode, before then the convection fan has already turned on, mine works normal to me. 
In start up mode the flame will at times hit the top plate, lots of flame and lots of heat.


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## CanadaClinker (Nov 15, 2009)

Rainforest said:
			
		

> CanadaClinker - you just reposted my posting. Did you want to add a comment?



Sorry about that..... finger hit the wrong button too quick ...then had to go back and edit..... see my message above .......cc :cheese:


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## Rainforest (Nov 15, 2009)

CanadaClinker - that 555 timer idea is very clever!  I'll study the pinout when I get a few minutes, and if I cannot figure out how you did that, I'll get back with you if you don't mind. Thanks!


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## CanadaClinker (Nov 15, 2009)

Rainforest said:
			
		

> CanadaClinker - that 555 timer idea is very clever!  I'll study the pinout when I get a few minutes, and if I cannot figure out how you did that, I'll get back with you if you don't mind. Thanks!


.....here's what the final product looked like before I paralleled it into the stove..... cc


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## GenghisJon (Nov 15, 2009)

Wow, I just ordered this stove today, this is good to know!


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## jtakeman (Nov 15, 2009)

I found this PDf of snap discs. But they are 1/2 not 3/4.

http://www.alliedelec.com/Images/Products/Datasheets/BM/SELCO_PRODUCTS_COMPANY/557-0001.PDF

I will keep looking!

Edit:

Here's a 3/4" PDF 

http://datasheet.octopart.com/SE-L165-Selco-datasheet-15322.pdf

Manufactors link:

http://catalog.selcoproducts.com/category/3-4-disc-thermostats?


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## Marbleguy (Nov 15, 2009)

Something not right there. I have the same 1200I and it works just fine on the low setting. Only thing that I notice happening on the low setting is the glass get dirty a lot quicker. From a cold start on low the convection blower comes on after about 8 to 10 minutes of the lighting of the pellets. Any chance they for some reason your fireplace would be colder on the left side? I know that the blower for the firepot is on that side. Is the right side maybe drawing extra inside air thru that side keeping it colder than the other? Just a couple of thoughts.


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## CanadaClinker (Nov 15, 2009)

Marbleguy said:
			
		

> Any chance they for some reason your fireplace would be colder on the left side?



I know that the back of my stove (where the snap disc 1 is located) is next to a large cold window in the winter.  I think if they had the snap disc more forward (nearer the firebox) then the delay for the blower to come on would be shorter.... most of the time (but not always), the 'back' of most pellet stoves are in a corner or (as for an insert), in a cold concrete fireplace.......my delay used to  be anywhere from 10 to 15 min (300 deg at output of exchanger)..... now with my timer cct, its 4 min on the nose from cold start with at least 90 deg air coming out of the exchanger...... cc   ;-)


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