Smoke back through hopper on shut down

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Java230

New Member
Sep 11, 2022
12
Washington
Grand teton ps20wts stove. Just installed.

On shutdown the exhaust dab seems to turn off and smoke fills the hopper and room.

Venting is straight out thr wall behind the stove, ~30" with vent cap.

Oak kit installed.

I get error 5 low pressure dectes at vacuum switch.

Do I need some vertical outside thr building? I thought that a straight out would be simple and effective. It works on my much older unit I have used in the past. But this one is far more modern.
 

johneh

Minister of Fire
Dec 19, 2009
4,395
Eastern Ontario
As soon as you turn the power off does the smoke start
or is it in about 15 min. that you get the smoke?
 
Last edited:

Java230

New Member
Sep 11, 2022
12
Washington
As soon as you turn the power off does the smoke start
or is it in about 15 minets that you get the smoke?
Immediately. It's like the exhaust fan just stops running.

I just had it running on medium, and dropped it to the lowest setting and it did the same error and went out....
 

Mt Bob

Minister of Fire
Oct 31, 2013
4,090
park county montana
I would say you have a control board or exhaust blower motor problem. Call your dealer, they will probably just want you to swap it out, give you another unit.
 

Java230

New Member
Sep 11, 2022
12
Washington
I would say you have a control board or exhaust blower motor problem. Call your dealer, they will probably just want you to swap it out, give you another unit.
Ugh hopefully it's just a control board. It's a heavy stove to get up the stairs..... It's in a treehouse.....
 

Mt Bob

Minister of Fire
Oct 31, 2013
4,090
park county montana
I agree. But it smokes me out really bad. It's a 200sf cabin.... And reeks.

Think jumpering the vac switch will help?
I doubt it will help. It sounds to me as if, when you turn stove down to low, the combustion fan dies, when it should not. That is what keeps the smoke going outside. If it doe have an issue, but the rest of the control board is still working, it throws a code of low vac, which shuts off the auger. Ideally, when you shut off stove, the combustion fan will keep running a long time, till there virtually is nothingleft in the burn pot that could burn. So perhaps do a few tests, watching closely.
 
  • Like
Reactions: Ssyko

Java230

New Member
Sep 11, 2022
12
Washington
I doubt it will help. It sounds to me as if, when you turn stove down to low, the combustion fan dies, when it should not. That is what keeps the smoke going outside. If it doe have an issue, but the rest of the control board is still working, it throws a code of low vac, which shuts off the auger. Ideally, when you shut off stove, the combustion fan will keep running a long time, till there virtually is nothingleft in the burn pot that could burn. So perhaps do a few tests, watching closely.
Yes my other (much older stove) runs for a very long time after shut down. It doesn't make sense to me that it would turn off the exhaust fan??

And running in low caused the vac error also?

Bad fan? The stove is literally new.
 

Mt Bob

Minister of Fire
Oct 31, 2013
4,090
park county montana
Yes my other (much older stove) runs for a very long time after shut down. It doesn't make sense to me that it would turn off the exhaust fan??

And running in low caused the vac error also?

Bad fan? The stove is literally new.
Does the combustion fan totally stop when the problem,smoke happens? Even if it should still be running? Then could be motor problem, or control board problem. If it "appears" to still be running, you could have a restriction in the flue, even at the back of the stove. Strange problems have happened to people when things like plastic packaging has been left inside the new pipes wen installed.
 

Java230

New Member
Sep 11, 2022
12
Washington
Does the combustion fan totally stop when the problem,smoke happens? Even if it should still be running? Then could be motor problem, or control board problem. If it "appears" to still be running, you could have a restriction in the flue, even at the back of the stove. Strange problems have happened to people when things like plastic packaging has been left inside the new pipes wen installed.
Yes fan stops, and the smoke from the firebox goes up the auger and out the hopper.

No restrictions (I looked in from the exterior and can see into the back of the stove) runs on high fine. Just on shut down cycle or very low.
 

Java230

New Member
Sep 11, 2022
12
Washington
Well...... The vac sensor has 3 wires.... Hard to jumper
20220916_215040.jpg
 

Java230

New Member
Sep 11, 2022
12
Washington
Well I have a theory. It's a 3 wire vac sensor, referencing 5v to ground.

I'm running the stove on an inverter and batteries. IE not always perfect 120v coming out.

Low voltage throws off the 5v converter and messes up the vac sensor signal?

It seems to not do it when running on the generator....
 
  • Like
Reactions: Ssyko

Mt Bob

Minister of Fire
Oct 31, 2013
4,090
park county montana
"I'm running the stove on an inverter and batteries."
Well that throws another iron in the fire, so to speak. Your vac code is because the fan stops too soon, not the other way around. The fan should stay running as long as the exhaust sensor sees heat, then for a bit of time after that, programmed in. I would bet your inverter is screwing up the control board itself, has been known to happen. Probably going to need a better inverter. Also, many electric motors do not like running off a inverter, and it can damage them quickly. Even my stove, when running on a quality UPS, both fams slow down. Not much, you have to be right at the stove to notice, and I can also see it on the Harman scan tool. They run hotter, and it takes life out of them. I would call the stove manufacturer, see what they say, they may say this may void your warranty, or they may have a reccomendation for a inverter. But it will not be a cheap inverter.
 
  • Like
Reactions: Ssyko

Java230

New Member
Sep 11, 2022
12
Washington
"I'm running the stove on an inverter and batteries."
Well that throws another iron in the fire, so to speak. Your vac code is because the fan stops too soon, not the other way around. The fan should stay running as long as the exhaust sensor sees heat, then for a bit of time after that, programmed in. I would bet your inverter is screwing up the control board itself, has been known to happen. Probably going to need a better inverter. Also, many electric motors do not like running off a inverter, and it can damage them quickly. Even my stove, when running on a quality UPS, both fams slow down. Not much, you have to be right at the stove to notice, and I can also see it on the Harman scan tool. They run hotter, and it takes life out of them. I would call the stove manufacturer, see what they say, they may say this may void your warranty, or they may have a reccomendation for a inverter. But it will not be a cheap inverter.
Yes, definitely add some complication. I have a better branded inverter I can try. The one I currently have is a pretty cheap unit so I'm not very confident. Running it off the generator is not the end of the world. We will be getting power at some point.

I have the sides off the stove, and can watch the exhaust fan, it stops within 10 seconds or so of the that code getting thrown.