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Too much draft incomplete combustion - stove goes out

Posted by johndough (My Page) on
Sun, Jan 1, 06 at 14:28

I have a Harman advance pellet stove 3 months old. it worked excellent for the 1st 2 months then it started giving Status 6 codes most often a couple times a day- sometime a day or 2 would go by ok ( status 6 = Incomplete combustion)I did all the complete cleanings and everyting in the book a couple of times, had the service guy come and he replaced the esp probe and it seemed mostly ok for about a week ( 2 status 6's in that time-so problem not really solved) now they are back and getting more often, sometimes every 2 hours - service guy again cant find anything, but thinks its because I have a 4" vent pipe instead of a 3" (originally I was installing into a diffent spot that had a long run and needed the 4", but I changed after I recieved the pipe to a total run of about 4 feet) - anyway, he thinks the extra inch is causing too much draft and needs to be changed to 3". does this make sense? the draft meter he puts on it pegs out to max setting, and he said it should be about 25-35, after manually blocking the vent pipe the only way the meter reads within specs is to leave a very small opening of about 1 sq inch ( too me that says even a 3" pipe woould be way too much if thats the cause)
some other observations I've made are

this only seems to happen when burning at a low burn to keep room at constant temp

when restarting after a problem ( and room temp is 8-10 degrees below therm setting), the burn is extremely low about 1" max above the pellets for sometimes a half hour before going full- normal start a good 10" flame happens immediately

hopper often fills with smoke during the low burn time

there is NO wind outside - during the 2 months of excellent operation it was often very windy out for hours on end

after the 1st service/probe replacement flame never went full for long ( maybe 40sec at a time here and there), stove never shut off due to bringing room to temp, as it did previously, for the entire week ( actually it never got the room to temp since the heat output was minimal)

I am still using the same lot of pellets but I have tried a couple bags of 4 other brands just in case

SO..what could be causing this problem? I dont think its the pipe since it ran great for 2 months

Any suggestions greatly appreciated


Follow-Up Postings:

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RE: Too much draft incomplete combustion - stove goes out

Sounds like your not getting enough fuel in the burnpot, this can cause "6" status blinks. Are you burning pellets that are extremely long in length (1 1/4" or longer) mixed in the bags you're burning. Long pellets will often bridge fuel in the bottom of the hopper. When you cleaned the stove did you remove the slider plate inside the feeder? This is a double sided plate, if it was put in upside down it will not push pellets properly (1/2 side up with edge).
Last thing would be a foreign object may be in the augar obstructing the fuel, plastic from bag, utilty blade, etc.
The key info is the flame height at start up, if there is a demand for heat the flame should dance off the heat exchangers at the top of the firebox.


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RE: Too much draft incomplete combustion - stove goes out

I had the same problem with my advance, I really don't think its the 4" pipe, I know a dealer here in Wisconsin and thats all he will install and never has a problem, If you have your outside air hooked up I'd be willing to bet thats the problem, I have been fighting with Harman for 2 years now because of smoke in the hopper and can't get a response from them.Try and disconnect the outside air and see what it does. Also go to their website and post a message on thear website comments page, its the only way to try and get a message to them, maybe if enough of us do it they will respond.If you want send your phone # to my e-mail address, I can call you and try to explain everything I've done to fix mine . fission1@charter.net


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RE: Too much draft incomplete combustion - stove goes out

Thanks for the replies

I MAY have found the problem thanks to your replies. I emptied all the pellets out then pulled off the cover held on by the wing nut, I pulled out the feeder plate and decided to stick my fingers where they probably shouldnt go, down the hopper and around the corner and what I felt there I dont think belonged there. The walls and top of that small chute area were EXTREMELY sticky. I couldnt find anyway to open that section up so I made a small metal scraper ( and stuck it on a string in case I dropped it) and spent a long time scraping the top and sides- 95% on it fell down to the auger but I was able to get a few chunks out - it looked like fudge brownie crumbs and just as sticky even with all the fines stuck in it. After scraping the best I could it was still tacky so I used alcohol on a rag and cleaned that off.
I reassembled and started it back up and so far everything looks good ( its only been a couple hours)

I assume this substance is Creosote, if it is how and why is it in that area?? and will this be an ongoing problem?

Murf1 - Have you checked this area on yours? do you think it could be from the smoke going to the hopper? - by the way, I do have outside air and have tried it disconnected same result - I will be leaving comments on Harmans website, I just want to wait a couple days and see what happens


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RE: Too much draft incomplete combustion - stove goes out

The sticky stuff your finding is from the smoke that gets up in your hopper,the more it happens the worse its going to get,your auger and slide plate are going to get gummy to a point its not going to work at all. I also asked if there is any chance that this build up could burn back into the hopper and never got an answer.Request / Demand that your stove be replaced, Harman told my dealer once this happens the stove needs to be replaced, I am now on my third stove, but Harman won't give any reasons or admit to any problems, they kept saying I was doing something wrong, Yet they keep replacing my stove, Hmmmmm....My dealer finally told them I was using the stove exactly as it was advertised to do, and just as the owners manual tells you to use it. I now will only run my stove in "stove temp" mode and no lower than a temp setting of 3.5, no outside air hooked up, anything other than that and I get smoke in the hopper and another junk stove. Not sure what else to do besides calling a lawyer and I really don't feel like dealing with that.Best of Luck to you. Hope I didn't depress you too much but I think people deserve to know when a product is possibily putting themselves and their family in danger and if this is not the case then all Harman needs to do is tell all of us that bought their stoves that they have tested and researched this problem and the is NO danger !!!!


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RE: Too much draft incomplete combustion - stove goes out

JohnDough,

If you're getting that much smoke in the hopper, by my theory, it is because the stove is starved for air. That's why Murf1 asked about outside air. If you don't have outside air, make sure that felt sound insulation inside the back cover of the stove is not closed up over the hole where a vent pipe would come out. At least that's how the Accentra is designed. When using outside air, the felt sort of presses against and seals around the pipe. When I disconnected my outside air, the felt started to close up again. So I took some aluminum flashing and some of that Nashua 304(?) tape and made a little snout for the intake.

Rather than repeat the same info here, I'll have you refer to the thread titled "Smoke in pellet hopper" it's about halfway down the second page of recent messages at the moment, the thread was started by Murf on Oct. 23 05.

Your 6 blink story is identical to mine. I had the problem throughout last year. This year it started again, so I read this forum and decided to try disconnecting my outside air. I haven't had the problem since, either on room temp, or stove temp. And I can run stove temp on 1 0r 2 without trouble. The room temp setting does still sort of smolder at idle, and I don't like that, so I just run it in stove temp. The actual room's temperature is stable enough that it doesn't swing wildly.

Draft is actually vacuum when measure as you do on the Harmon firebox. It isn't just about how much resistance there is for the air to exit, but also how much resistance there is for the air to enter. The 4inch pipe is not the problem. For anything to run, it needs airflow. The test meter doesn't check that, it only tests vacuum. If you have very high draft as you said, AND you had plenty of airflow, the incoming air volume would be so high the burnpot would look like a blast furnace. The intake (design) is fixed, and the power of the fan is fixed. The 4 inch pipe is less resistance than designed, but the real variables are at the intake. You might also have a the damper flap sticking in the intake.

Sbwm


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RE: Too much draft incomplete combustion - stove goes out

This same exact thing has happened to me!
The stove is 3 months old, and worked great for up to two weeks ago. Then daily it had the 6 blink error. Now it won't even run. The hopper used to fill with smoke constantly.

I checked the Outside air intake and it is not clogged. In fact, when pulled out from the stove, air from outside blows through it into the house on it's own as my heat leaks to outside. No blocks in the 4" outlet pipe either. Something has got to be causing the smoke buildup so once fixed I'll test no outside air pipe connected.

Anyhow, the slide plate is completely gummed up. I undid the wing nut by the motor and cleaned out a bunch of sticky residue, as well as tried cleaning the slide plate and reached as far as I could into where the pellets fall off the plate. The plate at least moves now without straining the motor. Still - no pellets make their way through.

I'm gonna have to call a place to come clear it out. Any recommendations on how to unclog it before having someone visit???? There's no way that I can to get to that side of the inside of the feeder. Should I try removing the slide plate altogether? The auger still spins without resistance (when chain disengaged).

- Drew


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RE: Too much draft incomplete combustion - stove goes out

Its been 2 weeks since my post about cleaning the gunk out of the chute. So to update..
after the cleaning the stove ran, but barely with minimal 6 blinks, the flame never got above the burn pot and I would have to have the feed maxed out. after a week of this I stopped at the dealer and talked to them about the problem - they have been having LOTS of Advance stove problems - the day after stopping at the dealer I recieved a phone call from them. They talked more to harman about what I found in the chute and guess what? a NEW stove was already being shipped However I was told to Shut down the current one IMEDIATELY and not use it period. A few days later the new one arrived and is installed and is working great. 1 week so far. I guess it has a new style motor and I dont know if its me, but the knob for the feed now seems to 'click' very slightly when turned. ( my imagination?)

Now that being said, I did notice 1 thing that sort of concerns me ( and please dont blame it on the pellets) When the stove goes into low burn ( I only run in room temp mode) and there is a very low flame, smoke comes around the left side of the ?Flame plate? (plate above the pot) and guess what is starting to accumilate there? a little black sticky substance.. if its there where else is it accumulating again?? when stove goes back into a bigger burn, no more smoke - I must say there has been no smoke in the hopper though. I am thinking the problems are from build up from lots of low burns the build up is preventing the pellets from feeding right - Speaking of which, I now can hear the pellets drop and NO motor noise at all - before I NEVER heard pellets drop and the motor was quite loud and hummed ( even when they replace the motor)I knew when it was feeding even when I was on a different floor of my house.
Responses I recieved before both on and off forum said they burned in Stove temp mode and that seemed to eliminate 6 blinks, could it be that in stove mode you dont get the low burn and hence no build up? It cant be my outside air intake or vent since I havent changed that. Obviously something with the stove itself

What are peoples thoughts?


Now to reply to DREW -- did you remove the plate ( from under the wing nut) and clean the bottom of it? I had alot of build up there. Also there is no way to disassemle the chute to clean it out. I looked and looked and asked the dealer. They said no also. I suggest calling you dealer ASAP about the problem have them contact Harman - after all the stove does have a nice long warranty.. ( and dont forget I was told to shut if off ASAP.. Why? fire hazzard?)


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