# Smoke at shut off



## Llama6429 (Apr 17, 2013)

Hello all,  I am running a pellet stove and it starts up great and runs great when it is burning.  However, when I shut it off it will go through its normal power down cycle with no problem.  Once all the fans and everything shuts down completely it starts leaking smoke into the house.  All the vent seals are good.  The majority of the smoke is leaking up through the hopper and some is coming out through the ash pan in the bottom of the unit. WHY???  I just vacuumed and cleaned it and that didn't help any. Please help!


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## pen (Apr 17, 2013)

I moved your thread into the pellet room of the forum.

Welcome to the site and good luck.

pen


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## Lake Girl (Apr 17, 2013)

Hi Dan, Welcome to the forum. First off, when you post a question for help, it is best to identify type of stove in the title...so what make/model of stove? That way you'll get someone with experience with that type of stove answering. How old is the stove? Beside the maintenance cleaning have you done a deep clean and cleaned your exhaust pipe? This is recommended after every ton of pellets. The exhaust pathways within the stove will collect ash and can usually be reached through clean-out ports (location depends on stove make/model). Some stoves have portions of exhaust pathways that are a little more difficult to reach... but that is where those with experience with that stove type will give you tips It is also recommended to pull the exhaust blower to clean that area and brush off the blades. Your manual should provide you with info on the deep clean. Unfortunately, some manuals are better than others.

What size exhaust pipe do you have, how long, how many elbows?  What elevation are you located at?  Exhaust pipe may be causing constriction too...


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## Llama6429 (Apr 17, 2013)

Hello, still Dan here, I changed my user name.  I'm running a US Stove 5500M King pellet stove.  For the intake vent I have one 45 degree elbow and is 2" in diameter and is only about 18" long. The exhaust has two 45 degree elbows, is 4" in diameter and is about 6 feet long. The unit is only 4 years old and it was installed by the previous owner. I took the exhaust apart and cleaned it really well but did not know how to get to the blower.  All the connections and joints were resealed really well. 

Thanks!


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## Llama6429 (Apr 17, 2013)

Also, what is an OAK? And would that help?  I sealed the two "trap" doors that lead to the ash pan and that helped with the smoke coming from there but I am still getting it leaking out thought the hopper/auger when I shut the unit off.


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## Lake Girl (Apr 17, 2013)

You have an OAK - the 2" intake  Size of the exhaust should not be causing constriction - 4" pipe.  Leaves exhaust pathways inside stove... I'm not familiar with your stove but hope the following helps... and someone else chimes in who has experience with this stove type  Is the stove surge protected and you have smoke and CO detectors in place?

Manual - https://www.usstove.com/index.php?route=cms/article&path=6&article_id=11
Page 22 has exploded view of interior of the stove.  You've pulled the ash traps behind the burn pot and vacuumed (part 40)?  Can you access the exhaust duct (3) from the ash traps and clean with a brush and vaccum (cheap dryer vent brush should work)?  Not sure if there are other pathways that could be clogged...  Depending on the type of gasket, you may want to get a spare before you pull the exhaust blower.  Red/Orange silicone ones seem to be pretty tough but the others seem to need replacement when you pull the part off.

Videos for repairs are also on US stoves website - just don't seem to have one for cleaning
https://www.usstove.com/index.php?route=cms/article&path=5&article_id=7

Keep us posted and I'll start another thread to redirect here... folks here like to see pics of your stove install when you get a chance


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## Llama6429 (Apr 17, 2013)

Can you tell I'm new at this!? Thank you so much for all the help! I hope it works. You have been super helpful.  We have CO and smoke detectors throughout the house!   

I've sealed the pan doors and I'm 99% sure that the air flow is good but for some reason when I shut it off, it's not. It leaks through the hopper. 

Picture will follow when I get everything operating smoothly.


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## TheMightyMoe (Apr 17, 2013)

How are you shutting it off? The exhaust fan typically stays on for a while after shutting it off, is the fan staying on?


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## Woody1911a1 (Apr 17, 2013)

thing is , is that the fans should stay running for a sufficient time so that there are no more smoldering pellets to give off smoke .


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## Llama6429 (Apr 17, 2013)

I shut it of by hitting the off button.  The fan stays running for several minutes and they shuts off.  Once the fan turns off the smoke starts to leak and we start coughing.  Is there anyway to keep the fan running longer when I turn it off? 

Thank you!


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## Woody1911a1 (Apr 17, 2013)

several minutes ?  sorry but i own a dif brand stove and the off button gives the fan 20 mins til shut down .   did your stove always shut the fans off so early ?


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## Snowmobileaddict (Apr 17, 2013)

Llama6429 said:


> I shut it of by hitting the off button.  The fan stays running for several minutes and they shuts off.  Once the fan turns off the smoke starts to leak and we start coughing.  Is there anyway to keep the fan running longer when I turn it off?
> 
> Thank you!


We have different stoves, however after experiencing smoke-back events after shutdown on more than one occasion, I performed 2 modifications on my stove.  One to prevent unburned pellets from bouncing into the ash pan, and the second to directly control the length of time that the combustion fan stays on after a normal shutdown sequence.

After performing these modifications, I have not had a smoke back in over 1-ton of pellet throughput.

My modifications are in this thread:
https://www.hearth.com/talk/threads...lled-on-bosca-classic-500.99855/#post-1358806

The first post in the thread addresses the unburned pellets bouncing into the ash pan and post #8 addresses the fan shutdown delay.


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## Lake Girl (Apr 17, 2013)

May want to call US Stove to speak to a technical rep.  Failing that, if your not comfortable with troubleshooting on your own, you could call a local stove shop to see how much a service call would be.  I'm with the above comments that your exhaust blower seems to be shutting down early. 

Keep us posted...


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## Lake Girl (Apr 17, 2013)

Cleaning video for US Stoves:


How did you seal ash traps?


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## Llama6429 (Apr 18, 2013)

I think the fan runs for about 10 or 15 minutes, ill have to time it and see if I can adjust the time it runs after shut off.  I'm also going to pull the exhaust fan apart as the video shows and clean it, and make the "bouncer" mod to see if that helps!  I can't thank you all enough!!


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## Lake Girl (Apr 18, 2013)

Try to get the spare gasket before you pull the blower JIC


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## AlaskaAviator (Apr 18, 2013)

If you ran about 3 feet of exhaust pipe vertically outside your house it may create enough natural draft to eliminate any smoke in your house.


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## Lake Girl (Apr 18, 2013)

Hope there is a surge protector on the 5500m - power fluctuations can create alot of problems with the motherboard/control board on pellet stoves.
Many use Tripp Lite - you can use the search box at the top to find threads for websites to purchase...


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## skibladerj (Apr 20, 2013)

Sorry i'm coming late to this party! I had some smoke issues with my stove (first year owner). After some time I realized that my problem was coming from smoldering material in the burn pot. I now clean the stove ever two days. This is normally just the burn pot, the glass and by the heat exchanger. Then once a month ill clean out the ash pan, trap doors, exhaust system, etc. . . .


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## stoveguy2esw (Apr 21, 2013)

not familiar with the product but their control sets look like a clone of ours, does the board have an adjustment for the low limit, the stove should be shutting down on both time AND temperature. if there is enough coaling in the front of the stove to make that much smoke the stove likely isn't cooled down as much as it should for the stove to shut the rest of the way off. if the board does not have such an adjustment i'd wonder if the low limit is either bad or simply out of calibration


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## marinecorpsvet (May 13, 2013)

Got a 5500m, heating 1100 sq ft of house. Burned 2 tons last winter. I found out than when you are shutting it down, for clean up, when you hit the shutoff button, raise the hopper lid to prevent the auger from putting any more pellets in the pot. This will allow the stove to go thru the shutoff stage, burn all thats left in the pot, and the fan will suck the smoke out.


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