Harman XXV slow feed and heat output problem

[astruna]

Just recently I noticed our Harman XXV was burning with a very low flame and little heat. Thought initially the temp setting was turned way down but it was still set to 4 in stove temp mode. The hopper had plenty of pellets so that wasn't the issue either. I shut the stove down and gave it a good cleaning. After relighting, the problem persists.

It appears that the auger will feed just enough pellets to feed a small flame, then no feeding for about 4 minutes at which point the flame is almost out. I through a handful of pellets into the burn pot to see how the stove would burn with more fuel and there was a nice tall flickering flame like normal until it died down again. Ran the stove overnight to see if the problem would correct itself and no luck. Glass and heat exchanger turned a sooty orange color (normally always a powdery white) and not much heat.

Just wondering if anyone with an XXV or other model Harman has experienced this problem and what the solution was. The stove is less than a year old and I'm pretty meticulous about keeping it clean. We burned almost 5 tons this winter and I cleaned the stove following the manual after each burned ton. The only thing I haven't cleaned yet was the main flue which I was going to do at the end of the heating season. Could a dirty flue cause the problem I described? Or, maybe the ESP probe is acting up? Thanks in advance.

 

[SmokeyTheBear]

A dirty ESP could cause what you are seeing.

 

[Delta-T]

dirty exhaust could also cause your problem

 

[lbcynya]

Silly question, but is the house cold? Mine runs on low when it's over 40...

 

[CJ-SR4ever]

Im thinking its a combination of a dirty ESP and a dirty / restricted venting, especially if you have burned 5 tons. I agree 100% with Delta-T.

 

[summit]

If you have had this stove for a while, I would check the feeder cleanout. Most folks don't know it's there, but it can become full of fines and thus restrict the movement of the slide plate in the bottom of the hopper... thus slowing the feed of pellets. If this is a new stove, I would check to make sure the slide plate is installed right side up. By right side, I mean the side with the offset "step" to it pointing up, as the bottom smooth side will not allow the fuel to agitate properly, thus not allowing it to drop thru properly into the feeder. I have seen this happen one or two times with brand new units.

 

[astruna]

Okay the problem persists. I removed and cleaned the combustion blower, cleaned out the exhaust flue with a 3" pellet stove brush, and checked the ESP probe. The probe was a little dirty with some creosote build up but nothing extreme. I cleaned off gently with a little scotch bright and glass cleaner and put everything back together. I was sure this had to be the problem but still a very small flame, even on a temp setting of 7!!. I had cleaned out the feeder the other day just before I noticed the problem so I will take a look to make sure the cover is on correctly.

Other than that, I can't think of any other reason the stove won't get hot. It is about 37 degrees out right now and we always run on "stove temp" mode so I don't think outside temperature should matter. Do these ESP probes go bad? It seems that when the flame gets very low (almost to the point of just embers) the feeder will kick in and add some pellets to the pot. Flame increases a bit and the distribution blower speed will increase until the flame gets low again. Then the cycle repeats itself. I timed about 4 to 5 minutes where no pellets are fed into the pot the pot at all and the feeder light is out during this time as well. I will check the feeder cover tomorrow and get back to you all. This forum is great, appreciate all the quick feedback. Thanks!

 

[CJ-SR4ever]

If the ESP goes bad the status light on the control board will blink 3 times. Yup, definately make sure the fines box cover is on correctly. Also, check your hopper. I have pulled out small pieces of the bags that restricted the flow of pellets into the auger, so make sure you have nothing but pellets in there. You said you cleaned the ESP with a scotch brite pad right? I would avoid using anything but a wet paper towel. If you use anything abbrasive, it will damage the probe. Did the probe look bent when you took it out? If it is bent it is no good and needs to be replaced. Do you have a surge protector that the stove is plugged into? The control board and ESP are VERY sensative when it comes to power surges.

 

[astruna]

So lo and behold, it turned out to be the feeder plate not being seated correctly. It was right side up, but the slot in the plate was not in contact with the feeder properly thus creating a small gap. It's really tight working back there so I can see how I missed this. At least I know now and will be more careful in the future. Anyway, the stove is cranked up to a 5 right now and the flame looks great!! Thanks everyone!

 

[CJ-SR4ever]

So lo and behold, it turned out to be the feeder plate not being seated correctly. It was right side up, but the slot in the plate was not in contact with the feeder properly thus creating a small gap. It's really tight working back there so I can see how I missed this. At least I know now and will be more careful in the future. Anyway, the stove is cranked up to a 5 right now and the flame looks great!! Thanks everyone!

Congrats on the fix! Indeed it is very tight back there. Glad to hear the stove is now working properly. Excellent job

 

[johnnycomelately]

Chalk one up for the good guys