smoke in pellet hopper

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rerick

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Hearth Supporter
Oct 27, 2008
21
CT
I have a p61a and sometimes I get smoke in the pellet hopper. It seems to occur when the hopper runs low and also when the stove is running in a low flame mode . I called Harmon and they said to increase the feed rate higher. They said maybe as high as 5 or 6 depending on the pellets used.
 
rerick said:
I have a p61a and sometimes I get smoke in the pellet hopper. It seems to occur when the hopper runs low and also when the stove is running in a low flame mode . I called Harmon and they said to increase the feed rate higher. They said maybe as high as 5 or 6 depending on the pellets used.

This will happen if you have an air leak
or not enough draft in your venting run. IE if you are just direct venting.
 
The stove seems to be tight in terms of an air leak. The adjustment for the draft setting came adjusted all the way up to high. It never happened until the last week or so. I have been running it for a couple of months now. I cleaned it once and it seemed better but not for long. The higher feed setting seems to have helped somewhat also. I wonder if the pellets I am using have something to do with it. They are Michigan wood pellets from Holland Michigan.
 
the smoke must be either drawn there (in case of a leak in the hopper or feed system) or forced there , due as rod said to a less than optimal exhaust velocity. how much smoke were you getting? just a wisp or two or a lot?
 
Yesterday when I opened the pellet box it billowed out. Sometimes it is just a little. But it didn't start until just a couple of weeks ago
 
do you see any leakage when the hopper is closed? or smell smoke? somthing is wrong either way , i'd still likle to know what the hookup looks like , can you describe your exhaust run starting from the stove and lay it out for me all the way to the cap?
 
I have a cleanout that goes in a 90 out the wall to a cleanout and the 10 feet straight up
 
rerick said:
I have a cleanout that goes in a 90 out the wall to a cleanout and the 10 feet straight up

ok, cleanout turned sideways , through the wall , then up 10 ft? or cleanout , the a 90 the through the wall and up? also , how long is the part going through the wall?
 
12 inches through the wall. The cleanout inside is on a 45 angle into the 90 to the 12 inch throught the wall to a cleanout and the 10 feet straight up
 
I don't understand, can you post a picture?
 
The ones I have are too large in terms of the file size. I will have to take a couple and post them tomorrow
 
rerick said:
12 inches through the wall. The cleanout inside is on a 45 angle into the 90 to the 12 inch throught the wall to a cleanout and the 10 feet straight up

ok i got ya, back to back 90 degree turns right off the stove ,(one being the tee)then through and up.

you will have a bit of backpressure from the two 90's but the draft adjustment availiable on the harman unit should be able to open enough to compensate. do you have OAK installed? also , do you have smoke in hopper while the stove is running or only after shutdown?
 
no outside air and the adjustment is all the way clockwise. Smoke happens whe running but it only seems to happen whe the pellets are low or the stove has been in a low flame mode for awhile. I tried to adjust it and I am told that it controls the motor for venting but I don't notice any speed differance whe I move it in either direction.
 
ok need a harman rep now , not sure about the range pot for the blower, i'd think there would be some discernable difference. im still not convinced you dont have an air leak in the hopper though
 
I called a Harmon service guy and he is coming but not till Dec 26. When I open the the hopper though the flame seems to get more air because it blows harder and when I close it the flame goes lower. In a high flame it runs strong. I checked the gasket on the hopper and it appears to be ok.
 
this a picture I just took The stove is running in a steady mode
 

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A picture of your venting might be helpful.
 
rerick said:
The stove seems to be tight in terms of an air leak. The adjustment for the draft setting came adjusted all the way up to high. It never happened until the last week or so. I have been running it for a couple of months now. I cleaned it once and it seemed better but not for long. The higher feed setting seems to have helped somewhat also. I wonder if the pellets I am using have something to do with it. They are Michigan wood pellets from Holland Michigan.
I would suspect that it needs to be cleaned more thoroughly
http://www.harmanstoves.com/maintenance/p38&p61cleaninginstructions;.pdf
Dirty stove can hinder airflow through stove and will affect draft reading especially in maintenance burn when comb blower drops to low draft.
FWIW turning feed rate up wont help ......if the room temp is satisfied, the stove will run in maintenance burn and ignore your feed setting
read the above link and tear it down and give it a good going over........... they really can't burn a ton between cleanings as is a common misconception, I would clean after about every 1/2 to 3/4 ton and noticed the efficiency was higher....
hope this helps...
 
That is a wierd looking flame pattern in the burn pot........
Have you cleaned under the burnpot?(the access has 2 wingnuts)
also check to make sure the air intake damper is swinging freely ( behind the stove)
And last since you don't have outside air how tight is the home?
 
This my pipe setup
 

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pics of venting looks like a total of 3-90 degree turns with about 12 feet of pipe. 3-90 degree turns is equal to 15 ft of pipe plus the 12 feet of pipe leads me to think you may have to increase the diameter of the outside pipe to 4 inches to prevent the stove from choking on itself.
 
Pellet stoves have to push the exhaust air through the vent pipe with the stove's exhaust fan. With less restriction your pellet stove will breathe easier and burn more efficiently. First let's clarify the word restriction. Restrictions come from several different items.

45 degree elbows
90 degree elbows
Horizontal distance
Vertical distance
Elevation where you live.

A rule of thumb equation we are using has been adopted by most pellet manufactures. The equation is called the sum of Equivalent Vent Length (EVL). All of the above mentioned venting restrictions have been assigned EVL values as follows:

Each 45 degree elbow = 3 EVL
Each 90 degree elbow and Tees with cleanout = 5 EVL
Each foot of horizontal run = 1 EVL
Each foot of Vertical run = 0.5 EVL

Elevations above 3000 ft with an EVL of 7 must adapt to 4 inch vent pipe.

If your installation is below 3000ft, we would need to do some math. The rule of thumb equations is that if the sum of the EVL is 15 or greater, then the pellet vent pipe would be increased to 4 inch diameter pellet vent pipe.


Here is the link: http://www.nevelsstoves.com/articles/Venting-your-pellet-stove.htm

Hope this helps. My setup adds up to 17 and works fine.
 
This issue has come up before, on certain Harmans there is a modification that is done to older stoves where they drill 2 holes in the back of the stove and install a tube in between them, this solved my problem for now, but someone else had the mod done is now getting the problem back. The new stoves come from the factory with this problem solved, So they say!!! Call your dealer and asked about it.
 
So if I increase the pipe on the outside of the house to 4 inch it will make it better ? I also cleaned the pipe today and their was an awful lot of crap in it. I've only been using the stove since the beginning of Nov. The dealer who sold me the stove said the pellets could be at fault also. They are Michigan wood pellets llc from Holland MI.
They seem to produce a lot of ash. Oh and to top it all the dealer says he is no longer a Harmon dealer. I called a few of the other dealers and they don't want to know anything about a stove they didn't sell. I tried to do business with the Harmon guy 2 miles from me early in the fall and he told me he didn't have any stoves and he wasn't sure if he could even get any. Harmon told me to call a Harmon dealer. This going to be a long dragged out thing I can see it coming.


I had a thought. What if I just disconnect the pipe going up the side of the house and put a termination cap on it ? Less pipe , Less restriction ?
 
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