Harman P43 Smoke In Hopper

[PJPellet]

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.

The OAK fits snuggly without needing a clamp of any kind. Before this problem started I had wrapped a foil tape around it just to keep it airtight. The flapper isn't sticking and it lifts nicely when the stove is running. Thanks for the ideas. Keep 'em coming!

 

[alternativeheat]

The OAK fits snuggly without needing a clamp of any kind. Before this problem started I had wrapped a foil tape around it just to keep it airtight. The flapper isn't sticking and it lifts nicely when the stove is running. Thanks for the ideas. Keep 'em coming!

Ya but no way to see if it's "lifting nicely with the stove running" with the OAK attached LOL !

 

[Gavin641]

Do you usually run your stove in the low ranges?what is your normal temp you run the stove at just curious. I know that it depends a lot on the outside temperature but is it mostly in the low temp range?

 

[bogieb]

Ya but no way to see if it's "lifting nicely with the stove running" with the OAK attached LOL !

I think he said he upgraded to the 3" OAK - which means the flex tube goes around the outside of the intake pipe instead of inside. Doesn't mean the flapper isn't sticking, but does mean the OAK can't be in the way. And removing the 3" OAK wouldn't have an affect on whether the flapper sticks or not if there is no clamp.

 

[alternativeheat]

I think he said he upgraded to the 3" OAK - which means the flex tube goes around the outside of the intake pipe instead of inside. Doesn't mean the flapper isn't sticking, but does mean the OAK can't be in the way. And removing the 3" OAK wouldn't have an affect on whether the flapper sticks or not if there is no clamp.

Theoretically of course LOL !

 

[PJPellet]

Do you usually run your stove in the low ranges?what is your normal temp you run the stove at just curious. I know that it depends a lot on the outside temperature but is it mostly in the low temp range?

I always run the stove in room temp mode. The stove usually runs in the mid ranges. If there is ever a time when it runs in the low ranges for more than a few days I will crank it up for a couple of hours to burn off any possible build up.

 

[PJPellet]

Ya but no way to see if it's "lifting nicely with the stove running" with the OAK attached LOL !

Last night I propped that little flapper open with a small magnet just to make sure it would stay open. No difference. My curiosity has me wondering what would happen if I just removed the flapper. Of course....if it improved things it would still be masking the real problem.

 

[Gavin641]

Yes that is good to crank it up and get some heat thru it.sounds like Harman fix for smoke in the hopper is to drill a hole in the hopper and oak inlet and run a tube but I still don't think that would be the way to go.Agree with you need to solve problem not mask it.

 

[bogieb]

Theoretically of course LOL !

Well, yeah, I would go for that.

 

[PJPellet]

After experimenting with my manometer I have discovered very little difference between OAK/no OAK, and the different venting configurations. Granted, my manometer is cheap and I am currently looking for a better one to buy.

The readings are exactly where they should be.

My findings with the venting:
I also did a smoke test to see how the stove vents during a power outage. Surprisingly to me, there was zero difference between straight out the wall with the pipe versus a three foot vertical rise. The same amount of smoke came out of the exhaust blower spindle hole at the back of the stove. I thought that extra length of vertical pipe would have provided for a better draft but in my real world setup it does not.

For now I am going straight out the wall with the venting and keeping the OAK connected. This setup does not give me smoke in the hopper.

Anyway that is where I am at now.

 

[alternativeheat]

After experimenting with my manometer I have discovered very little difference between OAK/no OAK, and the different venting configurations. Granted, my manometer is cheap and I am currently looking for a better one to buy.

The readings are exactly where they should be.

My findings with the venting:
I also did a smoke test to see how the stove vents during a power outage. Surprisingly to me, there was zero difference between straight out the wall with the pipe versus a three foot vertical rise. The same amount of smoke came out of the exhaust blower spindle hole at the back of the stove. I thought that extra length of vertical pipe would have provided for a better draft but in my real world setup it does not.

For now I am going straight out the wall with the venting and keeping the OAK connected. This setup does not give me smoke in the hopper.

Anyway that is where I am at now.

Odd.

 

[jp99]

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

I use the Dwyer Mark II manometer, and it works well for the stove.

You can also reverse the tubes for negative pressures, but this model does read a small amount of vacuum.

https://www.zoro.com/dwyer-instruments-manometer-u-inclined-mark-ii-25/i/G0818824/

 

[jp99]

This was an interesting thread to read from back around 2005. You may find some ideas there. It's clear this has been a problem before with some Harmans.

How far back up the auger does the fire go on your stove?

Also, did you check your draft at both the high and low combustion fan speeds?

(broken link removed to http://ths.gardenweb.com/discussions/2371637/smoke-in-pellet-hopper)

 

[PJPellet]

I use the Dwyer Mark II manometer, and it works well for the stove.

You can also reverse the tubes for negative pressures, but this model does read a small amount of vacuum.

https://www.zoro.com/dwyer-instruments-manometer-u-inclined-mark-ii-25/i/G0818824/

Thanks for the link. I have been thinking bout buying this one.

 

[PJPellet]

This was an interesting thread to read from back around 2005. You may find some ideas there. It's clear this has been a problem before with some Harmans.

How far back up the auger does the fire go on your stove?

Also, did you check your draft at both the high and low combustion fan speeds?

(broken link removed to http://ths.gardenweb.com/discussions/2371637/smoke-in-pellet-hopper)

Yep, I checked it at both high and low combustion speeds.

I read that thread a few weeks ago and just read it again now. After all of the things that I have tried it makes more sense reading it now. It gave me a couple of new ideas. I think I may pull the crossover tube off again and try to poke a coat hanger around in there just to see if some "pellet mass" has built up. Then maybe test run the stove without the crossover tube for a day. Just to see what happens.

When I have pulled the auger tube it appears that the fire goes back 1 1/2 turns. From my memory, which isn't all that great, I believe that this stove is still burning back to the same 1 1/2 turns that it always has.

The good thing is that I always clean the stove like an obsessive lunatic. As I work on the stove now everything is nice and clean which makes replacing this and replacing that much easier.

Thank you for the links and information. I appreciate it!

 

[Lake Girl]

Well the last comment on the link is very interesting ... modifying burn pot and some alteration on pressure relief tube.

 

[Mt Bob]

Well the last comment on the link is very interesting ... modifying burn pot and some alteration on pressure relief tube.

Well they used to modify the burn pots on some older stoves.Not necessary on newer ones,and some had burn pot up grades.The first repair/upgrade on older ones,esp. gummy stoves,was to drill a hole through the air chamber,then drill a hole into the auger tube,at 6 oclock position,then block hole in air chamber.Then they found out same result can be had by installing the nipples and rubber hose,much easier and faster.

 

[Mt Bob]

Check nipples and air hose are not plugged with dust.Check fines gasket is good.Stove possibly has developed an internal crack.

 

[PJPellet]

Check nipples and air hose are not plugged with dust.Check fines gasket is good.Stove possibly has developed an internal crack.

I have been leaning toward the possibility of an internal crack. I have replaced and tried everything that I and the good folks here at the forum can think of trying.

The stove will be six years old in February of 2017. It has always had light to medium use as it heats my small house very easily. Always cleaned very well, etc.

On a positive note the stove has less ash and buildup since the venting is shorter.

My new manometer will be here tomorrow. But I don't think that will show anything different than my other one. Maybe a rebuild is already in my future.