Smoking XXV Update

[mtnbiker727]

So I haven't posted in a while, and I've done a lot, and am still unsuccessful.

I discovered the two holes on the top of the burnpot were totally plugged, so I cleaned them out and sucked out the burnpot and air intake.
I scraped the hard creosote off the inside of the stove. I tried to take the burnpot off to check the gasket, but couldn't get the nuts to turn, so I gave up on that.
I pulled off the combustion fan motor and discovered it had 20 years of dust on the fans and 20 years of creosote on the internal fan. (When I bought the stove, I was told these parts were all brand new installed by a Harman Technician). Yeah... I cut the old fan off so I could get to the other fans and clean them. I put a new fan on and sanded the combustion plate (whatever it's called) to get the rust off so hopefully it would make a good seal to the stove.

I also discovered the little yellow thing inside the pellet hopper is some kind of filter for the vacuum system when I unscrewed it and heard a clunk down inside the stove. That's not a fun part to put back together when blindly reaching through the inner-workings of the stove. I found out the stove will not run without that thing hooked up (it won't shut itself off without it either).

After all of that I tried the stove and still smelled smoke.

So tonight I replaced the ash pan gasket, which wasn't as bad as I thought... the gasket is definitely better sealing than the previous one, but alas, my efforts were in vain (again). When the stove lit there was a lot of smoke inside, so I checked the door glass to see if it was leaking around it. I could not see or smell any smoke.

After about 5 minutes we could smell the wood-burning smell (sort of) starting to emanate from the stove. We debated back and forth whether it was paint curing or smoke... and previously we thought it was cigarette smoke that baked onto the stove from the previous owner (no idea if they smoked or not). So I was pondering how I could clean the fan side of the heat exchanger with compressed air without making a horrible mess inside the house when I decided to smell the vents on the side of the stove where the heat exchanger meets the top of the stove. This is where the smell is coming from.

When I cleaned the inside of the stove, I noticed the heat exchanger is held in with nuts. The heat exchanger is too big to fit out the door, and I can't figure out how to disassemble the stove to get to it. If I could get it apart, I can't find the heat exchanger for sale anywhere, so I'm not sure what that would accomplish. I would like to try to get the heat exchanger off and at least use stove cement to try to seal all the way around it. I guess I could do this without removing the heat exchanger...

I can't remember if my last post I talked about my local Harman dealer... but after the first "professional" install 7 years ago not using an appliance adapter, and puncturing the vent with screws, I wasn't happy with them. I called them and asked about the ash pan gasket, which they assured me was the normal rope gasket, because they have 40 years experience with Harman stoves, and that what I had read on the Internet was wrong. I ignored them and bought the correct part and will never call them or go to their store again.

When I discovered the burn pot holes were totally plugged, I decided to call another local dealer to ask for help. I discovered the guy who orchestrated the failed "professional" install 7 years ago now works for that dealer! He assured me there were no holes in that location on the burn pot, then when I told him to look at the stove in his show room, he then told me that he'd been doing it for 15 years, and those holes don't do anything. So yeah, I don't need to call them again either...

Sorry for the rant.

I'm just at a loss.

We paid way too much for this stove to not be able to use it, and I can't bring myself to sell it in this condition. And ultimately we still need to heat the back room with something...

 

[johneh]

The one thing to remember is that the pellet stove is a negative-pressure stove.
This means that any leaks before the combustion fan will draw air into the stove.
Smoke will only leak after the combustion fan. So smoke comes from after the
combustion fan, the chimney connection to the stove or the chimney pipes.
Does the chimney have a clean-out tee at the stove or close to it? the clean
out cap tends to leak on a lot of stoves if not properly sealed
Just my nickel's worth

 

[mtnbiker727]

The one thing to remember is that the pellet stove is a negative-pressure stove.
This means that any leaks before the combustion fan will draw air into the stove.
Smoke will only leak after the combustion fan. So smoke comes from after the
combustion fan, the chimney connection to the stove or the chimney pipes.
Does the chimney have a clean-out tee at the stove or close to it? the clean
out cap tends to leak on a lot of stoves if not properly sealed
Just my nickel's worth

If there was a leak because of a crack in the cast, or some gasket or weld that failed, I find it hard to believe that no smoke would ever come out of that crack.

The cleanout T is outside the house. I put RTV on the pipe joints inside the house twice. The only thing left back there is to put RTV around the stove connection with the cast iron pipe, which has a good gasket in it that I checked already. It's possible this gasket is leaking and the smoke is getting pulled in by the distribution fans which are right there, then blown out the front of the stove... I guess I'll try that tonight.

 

[Ssyko]

If it takes to long to ignite it will fill the firebox with smoke and go “poof” its lit. With that fire comes a positive pressure that can exit the stove around the heat exchanger tubes thus the smell of smoke. It is only momentary, but does implicate a lack of vacuum in the stove. Tired exh. Fan, dirty exh pipe's

 

[Golfeur]

The ESP probe at the stove outlet has a hole for the probe and a hole for the screw to secure it. If the probe isn't properly inserted or the screw isn't in place, a hole will be created allowing smoke to escape because this section is under positive pressure.

 

[mtnbiker727]

If it takes to long to ignite it will fill the firebox with smoke and go “poof” its lit. With that fire comes a positive pressure that can exit the stove around the heat exchanger tubes thus the smell of smoke. It is only momentary, but does implicate a lack of vacuum in the stove. Tired exh. Fan, dirty exh pipe's

That's possible... but the burning wood smell gets worse the longer the stove is lit.

 

[mtnbiker727]

The ESP probe at the stove outlet has a hole for the probe and a hole for the screw to secure it. If the probe isn't properly inserted or the screw isn't in place, a hole will be created allowing smoke to escape because this section is under positive pressure.

There's no screw for the ESP anymore.... but I put RTV where the probe meets the stove, because I thought this could be an issue.

 

[Oregun]

What if you put a smoke bomb in the firepot and ran the stove in test mode with the fans running without lighting the stove.
Maybe those would put out enough smoke to see where the smoke is coming out of the exhaust chimney or the distribution vent.
Could also try it in the dark and use a flashlight to better show the smoke.

 

[mtnbiker727]

What if you put a smoke bomb in the firepot and ran the stove in test mode with the fans running without lighting the stove.
Maybe those would put out enough smoke to see where the smoke is coming out of the exhaust chimney or the distribution vent.
Could also try it in the dark and use a flashlight to better show the smoke.

That's an interesting idea....

I have been behind the stove numerous times with a flashlight in the dark. I've never seen any smoke from anywhere back there.

 

[mtnbiker727]

So another attempt and another failure. I put RTV on the back of the stove where the cast iron pipe is bolted to the back of the stove. The white gasket didn't appear damaged, but I'm grasping at straws at this point. The stove smells the same as it did after every other attempt at fixing it.

What are the chances that there's a crack or a busted weld somewhere in the stove? How would I ever find it if there is one?

 

[doneill127]

Do you have an OAK. If not is it possible the smoke smell is actually outside and is getting sucked into the house though cracks around doors, windows etc ?

 

[Washed-Up]

Another method I’ve used…disconnect the igniter…put in test mode…smoke bomb/generator at the air intake and use a flashlight like you have been trying. Hope you get it figured out.

 

[Dataman]

They use Colored Smoke for leaks too. https://peacocksmoke.com/products/color-smoke-bombs-hvac-leak-detection-airflow

 

[mtnbiker727]

Do you have an OAK. If not is it possible the smoke smell is actually outside and is getting sucked into the house though cracks around doors, windows etc ?

yes, there is a 2 inch OAK hooked up.