Harman 52i insert ... pellets are only partially burning

[karen_in_nh_2014]

Hi, all. I have a Harman 52i insert in my fireplace, installed (professionally) back in 2013. Usually it works well, often great, but sometimes little things come up that I simply can't figure out no matter how many web searches I do.

So far this winter I've burned just over 4 tons of pellets (Cleanfire from woodpellets.com, same brand I've used for several years). I can kind of "mark" changes by tons since I do a deep cleaning every ton or so (i.e., every 40-60 bags -- yeah, I'm a bit nuts, I keep track of how many bags I use). First 2 tons burned great. During ton 3, I noticed that sometimes I would seem to get a lot of partially-burned pellets -- usually I would NOT get any error message and the insert would continue to work, it just seemed really inefficient. After 3 tons I did my usual cleaning and didn't have this problem at all (or very very rarely) during the burning of ton 4. Now I am on ton 5 (today I burned bag #206) and the "problem" is now the usual. It means (a) I'm cleaning out the ash pan twice a day and (b) of course I'm wasting pellets because a lot are only partially burned. The weird thing is, again there are no error messages (no blinks) AND the heat output is still really good -- i.e. it's heating my house fine, just not (apparently) very efficiently.

I thought maybe I had the feed rate too high so too many pellets were being fed (I read in a previous thread on this board that that can happen with "short" pellets), so I have moved it (over time) from 4 to 3.5 to 3 to 2.5 to 2 and even below 2 -- absolutely no change.

Oh, normally I keep the insert going 24/7 -- I turn it down periodically (had been several times a week, now a couple of times a day) to scrape the burnpot, empty the ash pan, etc, but otherwise I keep it on "manual" so once a fire is going, it KEEPS going. And it's never gone out.

Any ideas as to what is going on and what I can do to fix it? Again, heat output remains very good -- but I hate wasting pellets and I hate having to check on the ash pan (and see partially-burned pellets) twice a day.

Thanks in advance!

 

[DAKSY]

Have you pulled the cover off the fines box & cleaned that out? Is the cover on correctly?
Is the rubber gasket attached to the cover in good shape?

 

[bags]

Have you cleaned off your ESP during your cleans? Are you door rope gaskets in good shape? Is you exhaust venting clean?

 

[railfanron]

Is the cover on the pellet storage bin fitting tightly and sealing? Also what others have said.
Ron

 

[karen_in_nh_2014]

Thanks so much for the replies! This morning I shut the insert down (unplugged it) before I went to a work meeting -- got home a few hours later and it was cold enough for me to check on some things. All the seals seem tight, and there were very few fines in the box (I did a deep cleaning just before bag #191 so as of yesterday I had burned only about 15 bags since then), and I had cleaned out the exhaust too. So I'm still puzzled.

While the insert was unplugged I scraped the burn pot and vacuumed the insides, then I plugged it back in and re-started. The fire was on within about 15 minutes. I checked after an hour and all I'm seeing now are ashes -- no partially-burned pellets overflowing the burn pot (and making an inverted-V pile in the ash pan!). So somehow it seems to have fixed itself?! I am glad of course but I really like to understand how/why things happen.

On that note: if you don't mind, could you please write a few sentences letting me know why you suggested WHAT you suggested? That is, why would a problem with the fines box cause partially-burned pellets? I'm not questioning whether it COULD -- I just like to understand WHY.

I will write again if anything goes wrong! I switched to manual once the fire was going so it will just keep burning. My oil furnace is down and out (will have to replace it this summer, ugh) so the insert is now my main source of heat -- yesterday and today have been REALLY cold so I was bummed at having to check the ash pan every few hours.

I've gone through and "liked" all the replies. Thanks again!

 

[alternativeheat]

Are you sure you are getting a 100% cleaning ? I ask because another 52i owner a couple of years ago had a similar problem and all along he had been missing a clean out hatch. He pulled it , it was plugged and had to rod it out. His was bad enough he wasn't getting good heat but still, just sayin. I don't own the 52i, maybe someone else can direct you to all the passages in one.

When you say you cleaned the vent, are you speaking about the entire vent system or just within the stove ?

A dirty ESP can cause more pellet use or inefficient consumption, not sure about to this degree without throwing a code though. Still, have you cleaned the ESP probe ?

 

[karen_in_nh_2014]

Are you sure you are getting a 100% cleaning ? I ask because another 52i owner a couple of years ago had a similar problem and all along he had been missing a clean out hatch. He pulled it , it was plugged and had to rod it out. His was bad enough he wasn't getting good heat but still, just sayin. I don't own the 52i, maybe someone else can direct you to all the passages in one.

When you say you cleaned the vent, are you speaking about the entire vent system or just within the stove ?

A dirty ESP can cause more pellet use or inefficient consumption, not sure about to this degree without throwing a code though. Still, have you cleaned the ESP probe ?

RE: the deep cleaning, it's everything you can do without pulling the whole unit out (my service guy says I need that done only once a year, and he knows I burn 5-6 tons/year, and for the past few years he seems to have been correct). I DO use rods with those flexible brushes on the ends and push them up into the exhaust system.

RE: ESP probe, is that the one that you can only access by pulling out the whole unit? If so, I have NOT cleaned that -- the service tech comes once a year and does the whole cleaning routine beyond what I do every ton. So I understand that that may be an issue ... but the heat output remains really excellent and I'm not getting any error codes (no blinks at all -- the fire just keeps going), so it doesn't SEEM like it should be the ESP?

I checked about 20 minutes ago and I'm still seeing 90% ash in the burn pot (as opposed to yesterday, when I was seeing basically 100% partially-burned pellets). There is also very little ash in the ash pan -- and yesterday, I got that huge inverted-V pile of partially-burned pellets in the ash pan 3 times during the day. So something has definitely improved, but I don't know why or how. It's frustrating because I DO like to understand why something is going wrong and what I need to do to fix it. (OTOH, in the past I HAVE "solved" problems by unplugging/re-starting, so I know sometimes it's just flukey.)

I am keeping a close eye on it and will report back tomorrow! Thank you for the reply!

 

[fmsm]

RE: the deep cleaning, it's everything you can do without pulling the whole unit out (my service guy says I need that done only once a year, and he knows I burn 5-6 tons/year, and for the past few years he seems to have been correct). I DO use rods with those flexible brushes on the ends and push them up into the exhaust system.

RE: ESP probe, is that the one that you can only access by pulling out the whole unit? If so, I have NOT cleaned that -- the service tech comes once a year and does the whole cleaning routine beyond what I do every ton. So I understand that that may be an issue ... but the heat output remains really excellent and I'm not getting any error codes (no blinks at all -- the fire just keeps going), so it doesn't SEEM like it should be the ESP?

I checked about 20 minutes ago and I'm still seeing 90% ash in the burn pot (as opposed to yesterday, when I was seeing basically 100% partially-burned pellets). There is also very little ash in the ash pan -- and yesterday, I got that huge inverted-V pile of partially-burned pellets in the ash pan 3 times during the day. So something has definitely improved, but I don't know why or how. It's frustrating because I DO like to understand why something is going wrong and what I need to do to fix it. (OTOH, in the past I HAVE "solved" problems by unplugging/re-starting, so I know sometimes it's just flukey.)

I am keeping a close eye on it and will report back tomorrow! Thank you for the reply!

You should be pulling and cleaning the ESP probe every ton. Especially on manual burn.

 

[karen_in_nh_2014]

You should be pulling and cleaning the ESP probe every ton. Especially on manual burn.

Well, if I have to do that, I will (I will have to learn HOW), but I've never had to before (this is my 4th season with the insert). And again, the heat output is excellent and there are no error messages ... so why does it seem to you to be a problem with the ESP? (Not being argumentative at all -- just wanting to understand your reasoning.) Thanks!

 

[fmsm]

Well, if I have to do that, I will (I will have to learn HOW), but I've never had to before (this is my 4th season with the insert). And again, the heat output is excellent and there are no error messages ... so why does it seem to you to be a problem with the ESP? (Not being argumentative at all -- just wanting to understand your reasoning.) Thanks!

It is the "brain" and will adjust air/fuel. If it's giving/getting a bad reading it could cause your issue.

 

[bags]

The ESP can get all gummed or caked up with ash etc; and therefore not be reading the exhaust temp correctly. It reads what is going on and relays that back to the control board so the stove can make adjustments and what not to run at where you have it set.

Basically about everything mentioned also covers air fuel mixtures or vacuum etc; If you have bad door rope gaskets they could be letting in too much air and cause poor burns, lazy flames, or possibly incomplete burns. Same goes for the fines box cover. If anything is a bit out of tune or whack it can cause poor functioning for your insert. A clogged up exhaust vent can cause stoves not to run or run poorly.

Another note is that many times unplugging your stove and plugging it back in will do a reset of sorts and many times solves issues. Read up on your manual for your 52i. There is valuable info in it. There is also trouble shooting pages that explains the symptom and lists out the possible causes. Although harman stoves are mainly a set it and forget it type of operation they do require things to be done, cleaned, and maintained to ensure proper operation.

I'm not familiar with the 52i but most Harman stoves are much the same type of setup and operation. As for these other areas to clean or some rod deal I haven't a clue. There is a guy here that goes by Zeus that has and is up on the 52i. There are others too that may chime in or use the search bar and type in your issue and a Harman 52i. There should be plenty of info and reading to help you understand and sort things out.