I got a new woodchuck 526 this fall. I had an older woodchuck for many years that did not have a draft blower. This new wood furnace has a draft blower. It just doesn't seem to work consistently. It's hooked up to a fan limit control and its' own thermostat. Draft blower has an "on/bypass" setting and an "automatic" setting. (in addition to the on/off switch which is on) On automatic, I was told it's supposed to come on around 100 degrees and when ever the thermostat is calling for heat. As I've been testing it, I have the thermostat turned up to 80+ degrees. If I turn the draft blower to on it seems to work fine. If I switch it to automatic, even after a nice hot fire is going and the main circulating blower has kicked in, it doesn't always stay on. In fact, most of the time the draft blower turns off. But sometimes (25%) it works? I don't know what is going on with it. I ordered a new thermostat and tried it with the same results. Sometimes I turn it to Automatic and come back later and it will be on? Last night when I went to bed, I turned it to automatic when a good fire was going and the main blower was going. It wouldn't work. I left it in automatic, and when I woke up this morning, the draft blower was running and there were just a few warm coals in the firebox. I didn't stoke the stove, and as it cooled down, the draft blower did kick off like it's supposed to. The house temp has never been above 75 and I have always had the thermostat set above 80 so it should be calling for heat. Could it be a bad fan control limit switch? I called woodchuck and they said it shouldn't be intermittent. It should work or not work. But it's intermittent for sure and I don't know why?
Woodchuck 526 draft blower problem
- Thread starter Chaser77
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Sounds like there is a high limit in there. So it turns on at 100* but must turn off at a certain high limit temp, 130? so even though the t stat is calling, the high limit could be hit and not turn back on till it cools a bit with a call for heat.
In the fan limit control, there are three settings. One is set to 110, one to 160, and one at 200. When I called Woodchuck I think they told me the main circulating blower will come on at 160 then shut down when it drops below 110. They also said when the thermostat calls for heat and the firebox gets up to 110, the draft blower should go on when set to automatic. It doesn't? The other thing I noticed, is the main circulating blower is cycling on and off frequently even when the firebox has a good bed of coals. This morning the blower has cycled on and off over a dozen times in the past 30 or so minutes? Can the stove temp really be fluctuating that much? Do I just not understand how this system works? Is something wired wrong? It came all pre-wired from the factory. Is the fan limit control bad? In the past 5 minutes the circulating blower cycled on and off 3 times.
This is for the indoor blower only I think. indoor fan on at 160 off at 110, 200 is high limit. sounds like that is working. Do you have electrical schematics on what brings the induced draft motor on and off? If its the T'stat only, then you have a problem with that draft motor.
http://www.meyermfg.com/library_manuals/WOODCHUCK__12-21-15_.pdf
On Page 27 here, the wiring diagram can be found.
The draft blower works when turned on/bypass. Occasionally it comes on when the switch is in automatic. It should come on when the fire is hot and it is in the automatic position, but most of the time it doesn't. Every once in a while it does? I don't get it? I did try a new thermostat too with the same results.
On Page 27 here, the wiring diagram can be found.
The draft blower works when turned on/bypass. Occasionally it comes on when the switch is in automatic. It should come on when the fire is hot and it is in the automatic position, but most of the time it doesn't. Every once in a while it does? I don't get it? I did try a new thermostat too with the same results.
Ok, so your t-stat only operates the indoor fan. Your limit control, if it hits 200* shuts draft blower down. If your low limit does not reach 110* or falls below 90* your draft blower shuts down. According to the instructions you have to put the draft low limit in bypass till things get good and hot, then put it back to auto.
So you are either going off on high limit (not moving enough air) or going off on low limit (not preheating the unit) or (moving to much air) Hope this helps.
Man Makes me glad I got a set it and forget it unit.
So you are either going off on high limit (not moving enough air) or going off on low limit (not preheating the unit) or (moving to much air) Hope this helps.
Man Makes me glad I got a set it and forget it unit.
I think I understand that now. I'm thinking draft thermostat (labeled Draft low limit in diagram) is the problem. I had a good hot fire going, circulating blower was going. Draft blower was working when on bypass. I flipped it to automatic and the draft blower shut down. I took a wire and jumped it across the draft thermostat and the blower worked on automatic. I pulled the jumper wire out and the draft blower continued to work on automatic, but then in a couple minutes it shut off. I'm thinking something could be wrong/intermittent with that draft blower thermostat? So last night i just left the fan on bypass so it ran steady. This morning the fire was pretty much out, just a handful of coals. I flipped the draft blower to automatic thinking it would shut off, but it stayed running? I'm thinking of just ordering a new draft thermostat and trying that..it's only a few bucks.
laynes69
Minister of Fire
Your draft blower should not run when there is a hot fire. If the firebox gets too hot, the draft blower won't run. If your wall thermostat has a call for heat, and the firebox exceeded the limit temp, the draft blower should not be on. It should NOT operate all the time.
brenndatomu
Minister of Fire
??? Maybe I'm confused, (but I don't think so) but it sounds to me like it is working fine...
What t-stat you using? Some of them are setup to "cycle" the heat
I know it shouldn't run all the time. But even when the firebox is warm, and the wall thermostat is calling for heat, the draft blower won't run when on automatic as it should. If I turn it to bypass when the firebox is warm, it comes on. I know there is a high limit for the draft blower too at 200 degrees. That isn't being reached or the draft blower wouldn't work when turned to bypass I believe.
I'm using the wall thermostat that Woodchuck sent with the furnace. And I tried a new one of the exact same model. Honeywell Heat Only T87K1007. It's not working like I was told it should. The draft blower should come on at 110 degrees when the switch is on automatic and thermostat is calling for heat.I set wall thermostat at 80 while testing. Funny thing is a few times, like this morning, it seemed to be working like it should. It seems to be intermittent problem. Frustrating.
I don't think it's going off on high limit. It wouldn't work on the bypass setting if this is the case. And there's times where it isn't working when the fire is just warm, not even at 160 yet to kick the circulating blower on. You mention moving too much air? does too much air flow just cause the draft thermostat (snap disc type) to cool too much and reach low limit (90) therefore shutting off? Or are those things somehow sensitive to air flow somehow? Or strictly temperature controlled?
Yes, if your moving to much air it may be cooling the unit below 90. What fan speed do you have it on? Try lowering it and see what happens.
I have the 3 speed blower on low, but it is moving a lot of air. I think I figured out the "problem". The circulating blower was coming on at 160, like it should according to the fan/limit switch. The draft blower when on automatic was not coming on at that time even though it's on a separate click thermostat that is supposed to click on at 110. Seeing that those two sensors are right next to each other, I assumed that there couldn't be a 50 degree difference in temperature between those two locations that are only a few inches apart? Until I peeked inside the plenum and saw how the click disc thermostat of the draft motor is mounted basically flush with the side of the furnace and the sensor for the blower motor actually looks to extend about 6 inches into the furnace getting much closer to the smoke/exhaust pipe of the stove. Now it makes sense to me why the blower motor was kicking in at 160 and the draft fan on automatic would not run. I have an infrared temperature gauge. I used this last night to take the temperature of the side of the furnace near the click thermostat for the draft motor. When the blower kicked in on the circulating fan (I'm assuming at 160 like it is supposed too), the temperature near that click sensor was only 93 degrees. After the fire got nice and hot about 30-45 minutes later, I checked the temp near the click thermostat and it was 112. I switched the draft fan from bypass to auto and it stayed running, like it should. Part of the reason I may have been having so much trouble with this is because I have been starting smaller fires because the outside temp here hasn't been too cold. Most of the time the stove probably hasn't been getting hot enough to make the click disc thermostat trip on. I'm also thinking I may be moving too much air which is keeping that click disc cool. I'm not running the furnace connected to my cold air return. I have a filter on the blower box and restricting the air flow. I'll have to play around with that to get the right flow. I don't have a gauge to measure the air flow.
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