Harman P43 Smoke In Hopper

[PJPellet]

My new door gasket did not do anything to stop smoke in hopper with OAK attached. Fortunately the problem is very easy to repeat by connecting/disconnecting the OAK.

Yesterday I went over everything again with a very close look at everything. Luckily I have many spare parts on hand for my pellet stove so swapping parts out is free...just time consuming.

This morning I may (hoping) have found the problem. I won't know until the pellets in the hopper get low enough to test. My "swell" latch on the hopper lid I noticed was slightly loose. I turned the nut only about half a turn but it tightened up a bit and should give a better seal now. Whether this is the problem is yet to be seen and I am doubtful because I have tried so many other things.

Maybe over five years it loosened up just enough to let a little smoke in the hopper but not enough to noticeably affect the functioning of the stove.?.?

On the bright side I have nice new gaskets for a few years and I have "exercised" some of my spare parts. lol

 

[jp99]

So how's it working now?

 

[Lake Girl]

Hoping he reports back whether it was the latch or not...

 

[PJPellet]

Hoping he reports back whether it was the latch or not...

I apologize. I have been busy with other things while still trying to sort this out. Still smoke in the hopper.

Last week the stove stopped feeding pellets and I thought it was the auger motor but it turned out to be the auger and bearing piece. The bearing had gone bad after five years. I just replaced that two days ago, I had to order it, my dealer did not have one in stock. He told me they usually last 20 years. When I removed the defective auger assembly there may have been a tiny amount of slop at the bearing that may have done something with stove pressures.?.?.?.? Not sealing as well....maybe. As you can see I am grasping at straws.

I hooked the OAK backup after this and have been waiting for the hopper to get low enough to look for smoke. That should be later today or tomorrow. Personally I don't think it will help, probably a coincidence that the auger assembly went bad. But I remain hopeful.

I have been lucky for five years. I only had to replace the combustion blower. Still using the original ignitor. Of course I do keep it quite clean. I will let you know when the pellets get lower what happens.

 

[jp99]

Interesting, thanks for the update. I wish I could offer a solution but I don't know one for this.

I must have a quality PC45. In 8.5 years of ownership, all I've done is replace the vacuum switch. The door seals, motors, ignitor, etc., are all original. Some consumables (such as a stirring rod) have been replaced, but that's expected. Regular cleaning and occasionally putting some graphite flakes through the auger are about all I have to do.

 

[alternativeheat]

How long ago did you replace that combustion blower ? Also, how long and what diameter is that OAK tube ? Is there a screen mesh over the opening for the OAK and if so, how fine is the mesh ?

 

[PJPellet]

How long ago did you replace that combustion blower ? Also, how long and what diameter is that OAK tube ? Is there a screen mesh over the opening for the OAK and if so, how fine is the mesh ?

Combustion blower swapped out two weeks ago with known good one. It was my spare. About 24" OAK length, diameter 3 inch. Even with the OAK pipe disconnected from the OAK "wall" connection but still connected to stove affects the smoke/no smoke. What I mean is if I leave the OAK pipe connected to the stove but disconnected from the wall OAK inlet there is still smoke. Just that extra length of pipe causes enough of a difference.

I have really been playing around with things as you can see. lol

 

[Lake Girl]

If the auger bearing doesn't change things, is it possible that the change to a more aggressive blade on the combustion side is now starving the stove of air? Wondering what would happen if you increased OAK size temporarily to test as I realize you don't want a bigger hole in your wall... only to find it doesn't help.

PS Guess you could go back to original blade to see if that resolves smoke issue too...

 

[PJPellet]

If the auger bearing doesn't change things, is it possible that the change to a more aggressive blade on the combustion side is now starving the stove of air? Wondering what would happen if you increased OAK size temporarily to test as I realize you don't want a bigger hole in your wall... only to find it doesn't help.

PS Guess you could go back to original blade to see if that resolves smoke issue too...

Hello, thanks for the ideas. My stove actually came with the more aggressive blade. The double paddle blade. It had the upgraded blower too when purchased new.

We are thinking alike. I increased the OAK from the regular 2 3/8 inch up to 3 inch last week too. I thought it may help. It may have had a small effect on the level of smoke. I have thought about going to 4 inch but when I see how large the 4 inch pipe is, and as you mentioned, making the hole on the wall larger, I have not done that yet.

In the back of my mind I am still saying to myself, "It worked fine for 5 years with the 2 3/8 inch pipe."

The stove is working great and burning just as well as ever.....except for the smoke issue. This forum and you all have been very helpful. My dealer can come out for a $99.00 minimum and look everything over but I feel that I know this stove inside and outside. I could rebuild it without a problem so I feel very comfortable trying things to figure this out. Plus I don't see that they could figure it out any faster than us. Especially after talking to them on the phone.

Hopefully I can locate this issue soon.

 

[Lake Girl]

Have to come up with a safe way to test the 4" theory without enlarging the hole... through a window or doorway with the rest of the opening blocked off? Just odd that you have smoke in hopper with the OAK connection of any kind.

 

[PJPellet]

Well it wasn't the auger assembly....still smoke in the hopper, I just checked and got a face full.

 

[alternativeheat]

I'm confusing your smoky hopper situation with the guy with the staining glass LOL !

Did this smoke in the hopper start after you swapped out the old combustion blower with the "known good" one ? I think we might be getting someplace with the combustion blower. With the OAK on have you tried increasing the combustion blower trim screw for a little more voltage to the motor, even if temporarily ?

My P61 has about 8-9 ft of 3" OAK fwiw.

 

[PJPellet]

I'm confusing your smoky hopper situation with the guy with the staining glass LOL !

Did this smoke in the hopper start after you swapped out the old combustion blower with the "known good" one ? I think we might be getting someplace with the combustion blower. With the OAK on have you tried increasing the combustion blower trim screw for a little more voltage to the motor, even if temporarily ?

My P61 has about 8-9 ft of 3" OAK fwiw.

No, the smoke started just out of the blue last spring. I replaced the combustion blower because that's what I thought as well. My voltage screw is all the way for full voltage. I have a lot of spare parts on hand and I have swapped out many. lol With no luck. After the combustion blower swap out I put in my spare control board thinking that maybe it was feeding a lower voltage than it should....but that wasn't it either.

Thanks for your suggestions.

 

[PJPellet]

Just for grins I left the OAK attached and removed the three foot vertical section of venting outside of my house. Now the pellet stove vents through a 45 degree piece then straight out through about 28 inches of horizontal pipe.

No smoke with the three foot vertical rise removed from setup!

So for now would you guys run with no OAK and keep the three foot vertical section of vent or

use the OAK and remove the three foot vertical rise of vent pipe outside of the house?

This doesn't fix the issue but it keeps smoke outta the hopper.

Opinions?

 

[alternativeheat]

I'd investigate that vertical rise some more and if there is a T check that all out, that there isn't some sort of restriction, nest in there, carbon that won't brush out, or collapsing pipes. The vertical rise should increase draft not decrease it , as long as it's within spec. I seem to recall that we had a guy in here a couple of years ago who had a carbon mess at the top of his vertical rise and it eventually restricted enough to cause running trouble . I know that in brushing mine, the most mess is right around that 6-10 ft stretch ( mine, which is 4", goes up 26 ft all together).

Also check your outlet voltage under load, make sure that hasn't taken a dump on you.. I think it was you who said you were on a battery backup system, so make sure your voltage is up to snuff coming off that pack too. Even better , temporarily bypass that and plug into a known good outlet as a test. I went through that with a bad surge protector, fortunately it just up and died on me in short order so I didn't have to search it out. But the stove acted pretty wacky till that happened.

 

[Bioburner]

Getting or making a manometer to check your draft is what I would try. Maybe the voltage to the exhaust motor is barely enough to do the job

 

[PJPellet]

I'd investigate that vertical rise some more and if there is a T check that all out, that there isn't some sort of restriction, nest in there, carbon that won't brush out, or collapsing pipes. The vertical rise should increase draft not decrease it , as long as it's within spec. I seem to recall that we had a guy in here a couple of years ago who had a carbon mess at the top of his vertical rise and it eventually restricted enough to cause running trouble . I know that in brushing mine, the most mess is right around that 6-10 ft stretch ( mine, which is 4", goes up 26 ft all together).

Also check your outlet voltage under load, make sure that hasn't taken a dump on you.. I think it was you who said you were on a battery backup system, so make sure your voltage is up to snuff coming off that pack too. Even better , temporarily bypass that and plug into a known good outlet as a test. I went through that with a bad surge protector, fortunately it just up and died on me in short order so I didn't have to search it out. But the stove acted pretty wacky till that happened.

In the beginning I checked the venting. I even went back and re-checked later. All is clear and the pipe still looks great.

Unfortunately I don't have a battery backup system. I wish I did.

I have actually measured the voltage at the combustion blower with my DMM and it measures as it should.

These are good ideas and I appreciate them, keep them coming.

 

[Lake Girl]

I would run the stove with OAK and w/o vertical rise as long as you have the required distance from the house to end of exhaust. If you leave it that way, you might want to invest in a turbo cap as it reduces problems with staining on siding and sees to tolerated high winds. Basically how our stove is set up here

Give it the "power failure" test tomorrow. With mine, I get a wisp of smoke like a candle being extinguished. Exhaust fan evacuates most of the smoke from the stove...

 

[alternativeheat]

But this isn't the answer, the stove should be perfectly capable of 3" OAK and 3ft vertical exhaust. You can run without the vertical but that isn't what is wrong with the stove, doing so produces a patch that is masking another problem.. There should not be smoke in the hopper because you have a 3 " OAK and 3 ft of vertical rise.

 

[bogieb]

Just for grins I left the OAK attached and removed the three foot vertical section of venting outside of my house. Now the pellet stove vents through a 45 degree piece then straight out through about 28 inches of horizontal pipe.

No smoke with the three foot vertical rise removed from setup!

So for now would you guys run with no OAK and keep the three foot vertical section of vent or

use the OAK and remove the three foot vertical rise of vent pipe outside of the house?

This doesn't fix the issue but it keeps smoke outta the hopper.

Opinions?

I would leave the OAK and remove the vertical rise for now. If the pipe is the issue maybe some pin holes have developed or the connections are leaking that disturb the previous flow of exhaust (no, I have no idea how that would cause and issue, but there has to be something there that is the cause of your woes).

Another thought - did any building happen around you last spring that would affect the outside air currents or prevailing winds? Improbable as it sounds, even small changes could have an effect.

 

[jp99]

Getting or making a manometer to check your draft is what I would try. Maybe the voltage to the exhaust motor is barely enough to do the job

I'd like to second this recommendation. The stoves have a required spec for vacuum, and I'd be quite curious to see what the stove pulls in the two conditions. You should not have a significant difference between the OAK and non OAK set up, and both should meet spec.

If you haven't bypassed your vacuum switch you should have about the right amount under either condition but an actual value would be better to know.

 

[PJPellet]

I would leave the OAK and remove the vertical rise for now. If the pipe is the issue maybe some pin holes have developed or the connections are leaking that disturb the previous flow of exhaust (no, I have no idea how that would cause and issue, but there has to be something there that is the cause of your woes).

Another thought - did any building happen around you last spring that would affect the outside air currents or prevailing winds? Improbable as it sounds, even small changes could have an effect.

No new building around me. Good thought though!

 

[PJPellet]

I'd like to second this recommendation. The stoves have a required spec for vacuum, and I'd be quite curious to see what the stove pulls in the two conditions. You should not have a significant difference between the OAK and non OAK set up, and both should meet spec.

If you haven't bypassed your vacuum switch you should have about the right amount under either condition but an actual value would be better to know.

I checked the pressure back in this thread near the beginning. Both pressures were in the good range. But I think I am going to go back and play around with adding/removing OAK and venting and see what changes occur. Thanks.

 

[alternativeheat]

I'd like to second this recommendation. The stoves have a required spec for vacuum, and I'd be quite curious to see what the stove pulls in the two conditions. You should not have a significant difference between the OAK and non OAK set up, and both should meet spec.

If you haven't bypassed your vacuum switch you should have about the right amount under either condition but an actual value would be better to know.

I know that Dwyer makes an affordable manometer but I don't know which model it is that reads the correct negative pressure ?

 

[alternativeheat]

I checked the pressure back in this thread near the beginning. Both pressures were in the good range. But I think I am going to go back and play around with adding/removing OAK and venting and see what changes occur. Thanks.

Was this asked ( I think I might have asked it already), how are you clamping the OAK onto the stove and how tight ? Some Harmans have had the auto damper stick with an OAK tube attached too tightly. And anyway, make sure that flap inside there is nice and free regardless.