Harman insert exhaust concerns

[mbroughton02]

Brand new Harman Accentra 52i seems to be burning dirty. I completely cleaned the stove last weekend, and again yesterday. This is what it looked like yesterday, after only 5 bags of pellets:

Ash is very clumpy

Lots of black ash or soot on the door

The stove was installed by a Harman dealer. I noticed visible smoke from the chimney today so I decided to go up and see what they did up there. I have an outside air kit which they ran all the way to the top, as well as the exhaust.

I'm thinking I may have found some problems:
1) The exhaust fitting is a 3" fitting, which means there is a restriction at the end of the 25' long 4" stainless steel liner.
2) The fitting terminates only about 1" below the slate chimney cap, further restricting the exhaust.
3) The outside air liner was run all the way to this cap as well, but due to the slate chimney cap, the air that it's sucking in likely contains a lot of exhaust.

Thoughts?

 

[mikkeeh]

If I understand correctly its a 4” flue, restricted to a 3” termination?? Yea, that doesn’t make sense. And I would agree that the fresh air intake is way too close to the exhaust. I think you’re on the right track. Unfortunately, it doesn’t always pay to have professionals do the install. Keep us posted on what you find.

 

[mbroughton02]

Unfortunately, it doesn’t always pay to have professionals do the install

Yeah, I'm a big DIY guy. But New York offered a $1,500 rebate on the pellet stove for trading in a wood stove. One of the requirements was professional installation from a dealer on their list, so I had no choice unless I wanted to give up the rebate. But I would much rather have done the install myself.

 

[mikkeeh]

I hear ya. Many times you find the “professionals “ don’t know as much as you do. If it were me, I’d loose the 3” termination fitting and extend 4”pipe through the cap a couple of feet. Then a 4” weather cap on top of that. That way your current chimney cap protects the fresh air intake. JMHO

 

[alternativeheat]

I really don't think it's going to make a whole lot of difference if you terminate with 3 or 4 inch, the main run is 4. It would make even less sense if the run was 3 and the termination 4, by that point it's too late. For the sake of fit though I'd possible use 4 inch, and did on my own 35 ft run up the chimney.

However, if that intake is in line with the outlet, that's bad. I only ran 7 ft up my chimney with the OAK, so effectively have more than 25ft separation. Your OAK tube generally doesn't run to the top, there is restriction if too long, same as the vent restricts if too long, too twisted up etc. I think Harman allows a 10 ft run but in my case I also use 3" OAK tube. This stove breaths awesome too. It's ash is basically powder and it burns any pellet.

 

[JRemington]

Swing the insert out and unhook the air intake and see if that makes a difference. It looks like a combustion air problem. Did they set the draft? We are in NY and also do the NYSERDA rebate. The rules say the STOVE has to be installed and inspected by a certified pellet technician.

 

[rickwai]

I agree with JREM. Unhook air intake to rule it out. Then if that dont help get a couple bags of different pellets. We had some pellets in our area a few years back that burnt like that

 

[fastrac]

Good diagnostics on your part, Clean it, run it with out the slate and see how it burns .

You have correctly diagnosed the problem , Not you just have to get a new termination set up

 

[mbroughton02]

I took off the slate cap last night and let the stove burn for about 12 hours. Unfortunately it didn't make much difference. The glass was still pretty dirty and I got a cup of clumpy ash from 1/2 bag of pellets. So this morning I unhooked both the exhaust and intake from the stove so that I could get a better look at what's under the cap:

You can see that the exhaust is pretty restricted, going from a 4" down to a male 3" fitting. So for today I am leaving this chimney cap apparatus off completely. I reconnected both pipes to the stove and its burning now. I will let it go for 8-10 hours but will need to put the chimney cap back together before the end of the day, because right now rain and critters can just go right down the flue or liners.

Did they set the draft?

No, they did not test the draft with a magnehelic or do any draft voltage adjustment.

I agree with JREM. Unhook air intake to rule it out. Then if that dont help get a couple bags of different pellets. We had some pellets in our area a few years back that burnt like that

I have tried a few bags of at least 5 different brands of pellets, including Lignetics. The pellets I'm using currently are Barefoot. I tried several others as well. None were better, but some were worse.

 

[Cody901]

I’ve installed two of these stoves in the past year. The first stove I installed in my old house I made the terminations similar to your set up but I added a piece of metal in between the intake and exhaust and never had any issues. In my new house I terminated the intake in the chimney and used harmans chimney top cap and have had no issues with this setup either. I will attach acouple photos of the two setups. I would suggest the harman chimney cap and just cut your oak as far down as you can reach.

Sent from my iPhone using Tapatalk

 

[JRemington]

Actually the 3 to 4 is standard for a liner. You need to unhook the air intake and see if it makes a difference. You have a combustion air problem.

 

[rickwai]

When you have the stove out make sure the flapper is not sticking on the air intake. I have seen this happen once on a brand new unit. It took us 1/2 of a season to figure out what was wrong with that stove!

 

[mbroughton02]

When you have the stove out make sure the flapper is not sticking on the air intake. I have seen this happen once on a brand new unit. It took us 1/2 of a season to figure out what was wrong with that stove!

Thanks for the tip. I checked the flapper today. It was moving freely. Outside air liner has been completely disconnected from the stove as of this evening. The stove wasn't burning any better today with no chimney cap, so this is the next step. We'll see how it goes tonight/tomorrow...

 

[mbroughton02]

Ok so even with the outside air liner completely disconnected from the stove (so the stove is free to suck in room air), I'm still getting a dirty burn. I bought a magnehelic gauge on ebay which came in today.

Cold stove readings with OAK liner disconnected but exhaust connected:
Combustion blower @ full voltage = -.4
Combustion blower @ "max" factory setting 2,900 RPM = -.37 (Harman install manual calls for -.45 to -.50)
Combustion blower @ "min" 2,500 RPM = -.28 (Harman install manual calls for -.20 to -.26)

So clearly I am not getting adequate draft. After taking these readings I disconnected the exhaust from the stove and tried again. The readings did not change. There must be something wrong with the stove itself. Emailing the dealer now...

 

[JRemington]

What was the WCI pressure in the firebox?

 

[Mt Bob]

Well,unless Harman did some upgrade I am not aware of,your stove has the wrong impeller on the combustion blower.

 

[mbroughton02]

Fascinating, someone on the "Pellet Stoves" facebook group put out that possibility.

What I have:

What the parts diagram in my owners manual says I should have:

Very interesting...

 

[rickwai]

What was the WCI pressure in the firebox?

The 52i test port is tee'd into vac hose I think. There is no port in firebox like the original Acccentra

Well,unless Harman did some upgrade I am not aware of,your stove has the wrong impeller on the combustion blower.

Harman did change the fan and motor. I think it is a threaded motor shaft and fan blade instead of the set screw type. The look of the new fan reminds me of the Quad fans. I have not seen one in person yet.

 

[Mt Bob]

That shaft is not threaded,so I would assume he has a leftover 52i,not a touch control 52i,which means the impeller is wrong.Dealer probably needed it for a repair,then threw the quad impeller on there,thinking it would be OK.Yes,all the touch control harmans have an ebm/papst style motor.

 

[mbroughton02]

That shaft is not threaded,so I would assume he has a leftover 52i,not a touch control 52i,which means the impeller is wrong.Dealer probably needed it for a repair,then threw the quad impeller on there,thinking it would be OK.Yes,all the touch control harmans have an ebm/papst style motor.

This is a touch control 52i. Although the manual for the touch control version claims that draft is checked by removing a bolt in the lower left of the firebox, and there is no such bolt on this unit. Instead it has a piece of silcone hose sticking out near where the power cord connects behind the left panel, as @rickwai described. You're making me wonder if my unit was assembled using parts from several others...

 

[Mt Bob]

This is a touch control 52i. Although the manual for the touch control version claims that draft is checked by removing a bolt in the lower left of the firebox, and there is no such bolt on this unit. Instead it has a piece of silcone hose sticking out near where the power cord connects behind the left panel, as @rickwai described. You're making me wonder if my unit was assembled using parts from several others...

If dealer seems reluctant to help,call Harman.

 

[Mt Bob]

I blew up your picture,ya looks like a nut on fan, my mistake,There is a Harmon trained tech that can help,but was booted from here,he is on another forum.