We have a Harmen P43 Pellet Stove that is relentlessly smoking inside. I will note that we got it for free and it was in good condition but sooty when we picked it up. The combustion air smell of smoke fills quickly once we turn on the stove. Husfriend has been in HVAC for 30 years and we can't seem to figure out why the stove is throwing smoke through the warm air holes from the top of the stove. He's replaced ALL exhaust venting, high temp silicone on all connections, cleaned the freaking stove endlessly and we're using a high quality pellet. Door gasket is in excellent condition. There is no signs of smoke when he uses his laser in the dark. Not a single puff of smoke coming from the guts of the stove in the rear of the stove. Just a ton of smoke coming out of the hot air vents. He did notice the that there is exhaust smell coming out of the hole from the exhaust fan shaft. Should the hole be positive or negative pressure? What would cause the smoke to be present in the house but not anywhere in the rear of the stove or in the venting? It seems as thought that the exhaust is coming out of the exhaust fan shaft hole and being sucked into the circulation fan. Is there supposed to be a gasket in that area? Any help is much appreciated!
Harmen P43 ~ smoke smell inside
- Thread starter Travis Towsley
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If there is only a smell & no visible signs of smoke. I would check the top of the accordion heat exchanger, inside the distribution ports. Since it’s a used unit, that area may have been neglected & who knows what has settled on that surface. Pet hairs & dander, dust, aerosol residue… Once you fire it up, any of that stuff on the exchanger will heat up & smell. You can try to get in there with a bottle brush to loosen any debris & then vacuum it out, or simply run it in high until it burns off. Let us know how you make out.
Thank you Dasky for your thoughts on this ! We have had the stove plenty hot for a few hours on different occasions trying different things to try and see where the smell of smoke is coming from , We don't see any visible cracks in the upper heat exchanger part but ..... maybe there is something , the spot we smell smoke is from the rear at the exhaust fan shaft where it goes through the back of the stove , and i feel as though it is being sucked into the blower fan and being blown into the house , we will try to block some of the exhaust fan shaft hole and test it again and let you know .
ARC
Minister of Fire
Does smell go away after it runs for a while? Described your venting length, elbows? Smell should not come out of fan shaft hole it should suck in not out, if partial venting blockage you might get some to come out. I would especially check around the adapter that attaches to the exhaust housing that the vent pipe connects to seems to be a problem area for leaky venting.
Hello ARC , The stove is on a 45 in the corner with a 45 coming off the adapter to a 3 foot piece straight through the wall, a clean out tee and up 3 feet to a 90 with a exhaust tip
With The joints, high temp siliconed ,
The smell does not go away after long run times, I feel as though the smell is coming out of the shaft hole, even though I thought it should be sucking inward, but it is very possible that it is coming from another gasket in the system somewhere?
One other thing I noticed, the exhaust fan adapter plate on the inside of the stove is slightly warped, so high was able to straighten that out slightly, I did notice that the fresh air damper is wide open when it is running and it is blowing ash/smoke out the exhaust tip pretty well so I am assuming there is good draft, I do not know if the smoke coming out of the Shafter, because of that slightly warped plate? Should the exhaust fan shaft hole have a gasket there?
I have the same stove. I'm a little unclear on your post though. It sounds like you smell it, but can't see it, even with the laser. Since the stove is under constant negative pressure, you shouldn't smell smoke from the firebox area, even if the door gaskets were leaking. It's possible I suppose that there is a crack in the heat exchanger, but it would be rare.
The exhaust is another story though. If there are any leaks from the point where the pipe connects to the stove to after it leaves the house, that can give a smoke smell because it's under positive pressure. Leaks in the exhaust can smell, but not be seen once the fire is fully hot since there should be almost no smoke from the fire one it's going. The best way to see actual smoke from an exhaust leak is to watch with a flashlight as the stove starts up and there's actual smoke going out of the exhaust. I had a leak on mine in the pipe connection between the appliance adapter and the pipe going through the wall and that's the only time I could actually see it. I sealed it with silicone and aluminum tape.
I know that shaft area you are talking about, depending on the year, most models have a fiber gasket that goes between the motor and the housing that makes the shaft hole smaller. That gasket could be bad or missing, but it's not a tight seal around the shaft anyway. If the exhaust is good, clear, and sealed, and the gasket is good, the tiny bit from the shaft shouldn't be noticed at all. I don't get any hint of smoke smell from mine except when I open the door and scrape the pot twice per day. Here is a video that shows replacement of the combustion motor where you can see the gasket for the motor shaft.
The exhaust is another story though. If there are any leaks from the point where the pipe connects to the stove to after it leaves the house, that can give a smoke smell because it's under positive pressure. Leaks in the exhaust can smell, but not be seen once the fire is fully hot since there should be almost no smoke from the fire one it's going. The best way to see actual smoke from an exhaust leak is to watch with a flashlight as the stove starts up and there's actual smoke going out of the exhaust. I had a leak on mine in the pipe connection between the appliance adapter and the pipe going through the wall and that's the only time I could actually see it. I sealed it with silicone and aluminum tape.
I know that shaft area you are talking about, depending on the year, most models have a fiber gasket that goes between the motor and the housing that makes the shaft hole smaller. That gasket could be bad or missing, but it's not a tight seal around the shaft anyway. If the exhaust is good, clear, and sealed, and the gasket is good, the tiny bit from the shaft shouldn't be noticed at all. I don't get any hint of smoke smell from mine except when I open the door and scrape the pot twice per day. Here is a video that shows replacement of the combustion motor where you can see the gasket for the motor shaft.
ARC
Minister of Fire
There is no gasket around the shaft hole it should suck air in not out. Yes there is a gasket between the mounting plate and the exhaust housing but the shaft hole itself does not have one. Most leaks are around that adapter area, as Ocelot stated look very closely with a regular flashlight on start up. I just replace part of my venting to include the adapter it took me 3 tries to get the adapter to seal using rtv sealer it only leaked enough to see on start up and then only a small puff that you could see under the adapter. After it heated up you could still smell it behind the stove but could not see anything.
ARC
Minister of Fire
Get some kids bubble maker from the dollar store (or dish soap) bubble maker works better. Using a small paint brush paint it on the area around the exhaust blower, adapter and vent pipe it will bubble just like looking for a leak on a tire. I have gone as far as directly wiring the exhaust blower to direct power with a old lamp cord so it will run and the venting will not warm up evaporating the bubble liquid. It will show you were the leak is.
![[Hearth.com] Harmen P43 ~ smoke smell inside](https://www.hearth.com/talk/data/attachments/332/332489-2ea38f26e0936d043f62b0327d2833b0.jpg?hash=0Ld0rOdt7Z "[Hearth.com] Harmen P43 ~ smoke smell inside")
so what i did was , i lit some paper in the ash pot and let it smoke up real good , i could not see smoke anywhere , i let the exhaust fan turn on for 5 seconds and i unplugged the heater , it was then that i could see ( in the smallest amount ) using a flashlight , smoke coming from two super small pin holes in the siliconed joint at the collector and at the 45 , because i guess the smoke was built up in the piping , i have since replaced the 2 the parts and re siliconed the joints , so far so good
THANK YOU
AND THANK YOU to everyone that gave advise with this stove ,.Similar threads
