Smoke when door open


New Member
Mar 11, 2019
I got a Harman P68 installed on January 4th of this year. Worked great for the first month and a half, then I started getting smoke when I opened the door to scrape the burn pot. I did a thorough cleaning inside the stove, including the combustion fan blades, and the pellet cleanout hatch, but that didn't fix the problem.

I called the dealer and he said that because of the wet year we had, the pellets are creating a lot more ash than normal, and even he himself had to clean the stove pipe midseason because of smoke in his house. So I cleaned the entire stove pipe and the square exhaust channel, and recaulked all of the vent pipe seams (thinking the tape I used wasn't working). I have less smoke now when I open the door, but as soon as I start scraping I get smoke, which quickly travels through the house.

The stove is in the basement, with 3 inch vent pipe running 6 feet vertical, then 2 feet horizontal out the house. The dealer said the outside air kit wasn't necessary, because our house isn't tight enough to need it.

I'm running room temp manual mode (which is awesome!), and using a feed rate of 4. I have about 2 inches of ash in front of the fire, so I know I'm not running it too rich.

I don't get any error messages, everything works just fine, except when I open the door it's not sucking the smoke out like it used to.

I'm starting to wonder if manual mode just creates smoke because of the amount of burning pellets in the burn pot when I scrape it..... when I ran it in room temp auto for the first month, I did not have this problem, but I didn't like the stove turning on and off many times throughout the day, and much prefer a constant heat source.

I will be calling the dealer back to let him know the cleaning didn't completely fix the problem. He's probably going to want to send someone out to look at it, but I would rather not pay for service on a stove that's 2 months old, especially if it's something simple!

Any thoughts or comments?


Minister of Fire
Dec 2, 2017
agree with the oak. without it you are creating a negative pressure in the house. This is probably part of teh reason its pulling smoke into the house when you open the door...


Feeling the Heat
Oct 7, 2012
Northwest Lower Michigan
I would also recommend outside air kit. You might have enough drafts in your house to begin with, but then you fire up say a furnace, dryer, bathroom fan... now you might have negative pressure. Or if you sealed up those cold drafts. The OAK takes all that out of the equation and the stove runs isolated from the air in the house.

How did the dealer know? Did they run a test on your house? I was surprised but my house is 33 years old with original windows and the stove still wouldn't run right without an OAK.
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New Member
Mar 11, 2019
They said unless we had Superior Walls (prefabricated poured basement walls), or if it was a newer house, it wouldn't be air tight enough to need it. That's pretty frustrating to have to go back in after the fact and cut more holes through the wall and siding.


Minister of Fire
Sep 10, 2018
Newport, Wa
I use couple of air filters and shut it down completely before cleaning. I have Harmon XXV with OAK. I use 2 of these.

I just put AC filter on the box fans I use to move the air down the hall. Going to not do HOT CLEAN because it lets smoke out. Just a little and it bothers Wife. Plan on not using Vacuum (Loveless Cougar). Also not going to do daily clean, seemed waste of time and just clean it 2x weekly.

I have ash problem with film on windows. This seems to stop it so far.

I have yet to see any holes in the burn pot get clogged. Will keep an eye on it.


Minister of Fire
Oct 25, 2010
Titletown U.S.A
Run from any dealer that tells you you don't need an OAK, IMO. If they don't know the basics of differential pressure in a negative draft stove they shouldn't be in the business.
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Minister of Fire
before we added an OAK, I can remember the grandkids sitting on the floor watching tv and saying it was breezy on the floor.
I felt it and it was a cool air draft going back to the stove..
after the OAK was installed, it disappeared........
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