Harman XXV turns off after filling hopper

[Whatever Dude]

I moved into a home with a Harman XXV last year. This is our first winter using it, but its been there since winter of 2005. (Just FYI, we had the ESP replaced before this heating season since it was continually registering an error. Besides that, i lubricated the auger feed chain cause it was catching ever so slightly on the sprocket and "clunking" when the tooth slipped into the chain. No other issues.)

Here is a timeline of the problem:
Monday night, around 9 PM: I fill the hopper and go upstairs to bed. Sometime before Tuesday morning, the stove shuts off. A nearly full hopper indicates it didn't run that long after filling.
Tuesday afternoon around 4 i clean the stove (it had been 6 days since the last cleaning) and restart it. It runs fine overnight, and then stops within 15 minutes of me filling the hopper on Wednesday morning. I leave it off for the day.
Wednesday afternoon around 4 I turn it back on (hopper remains full from yesterday) and it shuts off again Thursday morning (today) about 15 minutes after I fill the hopper.

SO...it seems to run just fine for about 12-14 hours, and then shuts off about 15 minutes after I fill the hopper.

I checked the hopper lid, burn pot access panel, and door gasket. All three are tight/intact. I made sure the hopper lid was closed tight after the initial occurrence, and it still happened the next time so thats not it. I thought perhaps an extra windy day was making it shut down, but it's getting so repeatable that I'm not sure thats it.

I get no blinking status light, so thats not helpful. And it always fires up normally after i restart it.

Could a partially blocked flue be the problem? I was planning to clean it after this heating season. I did a full cleaning (except for the flue), including pulling the combustion blower, after approximately 1-ton of pellets were burned. The combustion blower seemed pretty clean. The previous owner told me he cleaned the flue once per year, but its possible its now gone two years without cleaning, depending on when in the year he would typically clean it, and when we closed on the house.

I don't have a magnehelic gauge, or amp meter, but does it sound like a low draft voltage problem? Seems odd that it would occur now, after burning almost 2 tons of pellets.

Thanks in advance for any thoughts you can provide.

 

[Delta-T]

after it shuts down, do you notice the blinking status light?? if so, how many blinks?

 

[Whatever Dude]

The status light doesnt blink at all after shutdown.

The light remains lit during operation, (and blinked appropriately when we had the ESP probe issue) so i know the light functions.

 

[PDawg]

I have the same problem with mine. I fill it at nightbefore going to bed, when I checked the stove th follwing mornig it was out and the hopper was full. I was runing in room mode, I switched to stove mode and it does not happen. The second isuue I have with mine is that it will not shut down. I have to leave the hopper door open to stop the feed cycle.

 

[chris288]

I have the same problem with mine. I fill it at nightbefore going to bed, when I checked the stove th follwing mornig it was out and the hopper was full. I was runing in room mode, I switched to stove mode and it does not happen. The second isuue I have with mine is that it will not shut down. I have to leave the hopper door open to stop the feed cycle.

If the ignitor is in manual mode the stove will not shut down unless it runs out of pellets in either stove temp. or room temp.

 

[Whatever Dude]

I have the same problem with mine. I fill it at nightbefore going to bed, when I checked the stove th follwing mornig it was out and the hopper was full. I was runing in room mode, I switched to stove mode and it does not happen. The second isuue I have with mine is that it will not shut down. I have to leave the hopper door open to stop the feed cycle.

I'm running in stove mode. I havent tried to see if the problem occurs in room temp mode.

 

[Whatever Dude]

If the ignitor is in manual mode the stove will not shut down unless it runs out of pellets in either stove temp. or room temp.

Is this safe? I figure the stove is shutting down for a reason, which I'd like to solve rather than just overriding it. But I could be wrong.

 

[Delta-T]

If the stove is in "room temp" and close to the desired temp in the room...what you are describing sounds normalish to me.

 

[chris288]

Sorry, didn't mean you to take that as a possible solution, just something for you to check, along with your thermocouple. With stove in room temp mode and ignitor on manual the stove will heat the room to the desired temp. and then throttle back to what is called maintenace mode which will maintain the lowest possible heat output until the thermocouple calls for more heat without ever shutting off.

 

[Whatever Dude]

I'm operating in stove temp mode.

I havent even tried to replicate the failure in room temp mode, cause I never operate there.

 

[Whatever Dude]

Sorry, didn't mean you to take that as a possible solution, just something for you to check, along with your thermocouple. With stove in room temp mode and ignitor on manual the stove will heat the room to the desired temp. and then throttle back to what is called maintenace mode which will maintain the lowest possible heat output until the thermocouple calls for more heat without ever shutting off.

I see. In any event, it can't be the thermocouple, cause I'm in stove temp mode when this failure happens.

 

[chris288]

Sorry, didn't mean you to take that as a possible solution, just something for you to check, along with your thermocouple. With stove in room temp mode and ignitor on manual the stove will heat the room to the desired temp. and then throttle back to what is called maintenace mode which will maintain the lowest possible heat output until the thermocouple calls for more heat without ever shutting off.

I see. In any event, it can't be the thermocouple, cause I'm in stove temp mode when this failure happens.

Sorry, PDawg was the one running in room temp mode when his stove was shutting down, having the ignitor in manual mode was in reference to his question.


While running in stove temp mode, the stove should never shut off unless it runs out of pellets, why it would shut off after filling the hopper, maybe a flaky hopper door switch ?

 

[Delta-T]

stove shutting down in "stove temp" with no blinking lights is very strange indeed. any shutdown in stove temp that is not initiated by the user should set the status light blinking in some pattern.

 

[chris288]

stove shutting down in "stove temp" with no blinking lights is very strange indeed. any shutdown in stove temp that is not initiated by the user should set the status light blinking in some pattern.

My thoughts exactly....

 

[Whatever Dude]

Hmm...maybe I'll try to make it happen tonight by waiting up for 15 or 20 minutes after I fill it this evening.

 

[Delta-T]

give the stove about 50 minutes after it shuts down before you do anything...the blinking status lights are connected to timed events.

 

[Fixedblade]

Greetings: I have a P-68 and have a very similar situation after filling the hopper with pellets. I run it stove temp mode. I think it has something to do with the pellets bridging and not flowing into the feed mechanism. Sometimes I'll notice the fire going out after filling the hopper and I'll open it and push a wooden yardstick down into the pellets and they start to flow. You can hear them drop into the slideplate. It seems to be happening more often so I wonder what causes it.

FB in Vt.

 

[Whatever Dude]

Greetings: I have a P-68 and have a very similar situation after filling the hopper with pellets. I run it stove temp mode. I think it has something to do with the pellets bridging and not flowing into the feed mechanism. Sometimes I'll notice the fire going out after filling the hopper and I'll open it and push a wooden yardstick down into the pellets and they start to flow. You can hear them drop into the slideplate. It seems to be happening more often so I wonder what causes it.

FB in Vt.

Interesting. That might have something to do with it, but I'd expect to get the status light blinking if it ran out of fuel.

Anywho, today I came home and tried to fire it up. No luck. I ran it in test mode several times and still didnt see any fuel coming from the auger for a long time. I checked the slide plate cam arm, which looked normal. So i took most of the pellets out of the hopper by hand, until I could see that the slide plate was opening, and the pellets were falling in. After that, it fired up normally (now that it had fuel, of course it would). Perhaps, if it was bridging, as I shifted the pellets around any bridging was fixed, and it started feeding again.

I let it run for about 20 minutes, then dumped a full bag of pellets back into the hopper (the action that had been causing shutdown). Its been 15 minutes since then, and still running.

I'll have to wait and see what happens tonight or tomorrow morning. I'll keep this in mind though. I can't see how it could possibly bridge given how small the pellets are and how big the hopper opening is, but who knows?

Edit: I also cleaned the ESP (wiped it with an old tee shirt), pulled the combustion fan (looked nice and clean), verified the flue was in good shape (perhaps 1/8" of creosote around the inside diameter...which i didnt think was anything to get worried about).

 

[summit]

bridging is a possible explanation. try not filling the hopper so full, see if it repeats itself

 

[summit]

feeder box might be full of fines... have you pulled off the cleanout plate?-

 

[Whatever Dude]

feeder box might be full of fines... have you pulled off the cleanout plate?-

I have once this year, and vacuumed it all out.

I have fill it twice since restart yesterday, with no known issues. I'll try not topping it off on the next fill to avoid bridging. Looking good for now at least.

Thanks all, for the tips/tricks.

 

[tinkabranc]

This may sound kinda silly, but be sure you don't push the pellets down in the
hopper trying to fit more in. This will cause bridging as well.

 

[Whatever Dude]

This may sound kinda silly, but be sure you don't push the pellets down in the
hopper trying to fit more in. This will cause bridging as well.

Hmmmm....i wouldnt say i was pushing them down, but more side to side, but maybe that was part of it. I never knew that bridging could even occur.
Thanks for the info everybody....i'll keep an eye out for the bridging in the future and check that first.

 

[Whatever Dude]

So i burned 2 or 3 bags successfully before the problem happened again today. Since it's saturday, i was able to watch it happen. It appears that I am getting some bridging. After filling today, the stove shut down. Typically when the auger turns, i can hear the pellets dropping down into the auger. I let it run for several fill cycles, and couldnt hear a single pellet dropping. So i poked a stick down into the pellets, and I could feel a point where the resistance decreased (once i poked through the bridge). It does appear there are some pretty long pellets in this latest bag, so maybe that is working against me.

I guess i'm still amazed that it would only seem to happen right after filling, and not at some other random time.

 

[checkthisout]

So i burned 2 or 3 bags successfully before the problem happened again today. Since it's saturday, i was able to watch it happen. It appears that I am getting some bridging. After filling today, the stove shut down. Typically when the auger turns, i can hear the pellets dropping down into the auger. I let it run for several fill cycles, and couldnt hear a single pellet dropping. So i poked a stick down into the pellets, and I could feel a point where the resistance decreased (once i poked through the bridge). It does appear there are some pretty long pellets in this latest bag, so maybe that is working against me.

I guess i'm still amazed that it would only seem to happen right after filling, and not at some other random time.

Isn't that something? A few posts later and thanks to other readers you have found your problem. Imagine being a tech from a Stove Shop trying to get your problem resolved. He would think you were crazy and lying and you would think he was a jerk for giving you horrible customer service.

Think of how long it would have taken you to figure that out without the help of this forum.