Harman HF60 not making enough heat

[cce3]

I cleaned the boiler last Saturday and I noticed that the temp gauge doesn't go above approximately 150 F, it usually goes above that. My min-max settings are 180-170 F.

I had to close some zone valves half-way so heat will go pretty much to the living room and upstairs area, but living room has been @ 62-63F and not going up (I usually have it at 66 F).

The flame is not lazy and seems to be normal. I cleaned it again today but no joy with the issue at hand.

It's our second winter in this house and had no issues like this last year. Utility room is beside the garage and I hang out in the garage comfortably with 70 F temp. It's been down to 60-62 F since Saturday.

Please advise for troubleshooting tips. Thanks.

 

[skalor]

No change in pellet brand? Did you clean the flue gas temp probe?

 

[cce3]

Same pellet brand as last year's.

Temp probe? Where is this located?

Edit: Found it with help of YT. Just cleaned it and will advise how it goes.

 

[cce3]

Cleaned the ESP sensor last night and temp went up to about 160 F then went back down to 150F. I went to bed thinking that's the issue since temp went up before it went down again.

I called the people who installed it 10+ years ago if they have the sensor in stock and luckily yes. I replaced it and still same issue.

I checked all the connections on the control board and seems to be ok.

Anymore advise? Would the control board fail like this?

 

[cce3]

I just opened it again and checked the room sensor, saw when I was checking the control board.

This sensor goes into the boiler. What is it sensing? Someone please explain.

 

[skalor]

I just opened it again and checked the room sensor, saw when I was checking the control board.

This sensor goes into the boiler. What is it sensing? Someone please explain.

A stove would use a room temp sensor, boilers use a water temp sensor and that's why it's running into the boiler. Probably just a different temp range thermistor. It could be reading wrong and if you want to throw parts at it, maybe replace it. Could be the potentiometer has a dirty spot in it or is bad. Try spinning the temp knobs back and forth a few times to clean the contact area. Are you running it in auto or manual? What feed rate are you running? Run the highest feed rate possible that keeps the active red coals about 1.5" from the falling off the edge of the burn pot. The feed rate is in 10s of seconds per minute so a 5 would mean the max time it will run the feed motor is 50 seconds per minute. If you turn it to 6 the feed motor should stay running if it's below the temp settings, and the flue temp isn't too high. It will stop feeding if the fire is large enough and the flue temp is high though so keep that in mind. If it doesn't run constantly you may have a leak on the hopper door, bad door seal, or clogged vacuum switch. I had a clogged vacuum switch with mine when I first picked it up used and it would run intermittently and not produce much heat. May or may not be your problem.

 

[cce3]

A stove would use a room temp sensor, boilers use a water temp sensor and that's why it's running into the boiler. Probably just a different temp range thermistor. It could be reading wrong and if you want to throw parts at it, maybe replace it. Could be the potentiometer has a dirty spot in it or is bad. Try spinning the temp knobs back and forth a few times to clean the contact area. Are you running it in auto or manual? What feed rate are you running? Run the highest feed rate possible that keeps the active red coals about 1.5" from the falling off the edge of the burn pot. The feed rate is in 10s of seconds per minute so a 5 would mean the max time it will run the feed motor is 50 seconds per minute. If you turn it to 6 the feed motor should stay running if it's below the temp settings, and the flue temp isn't too high. It will stop feeding if the fire is large enough and the flue temp is high though so keep that in mind. If it doesn't run constantly you may have a leak on the hopper door, bad door seal, or clogged vacuum switch. I had a clogged vacuum switch with mine when I first picked it up used and it would run intermittently and not produce much heat. May or may not be your problem.

Would the water temp sensor only sense the high temp (to slow down the flames when it hits the max temp)? I'm willing to replace that, trial and error. What would be the ohms reading using a multimeter for this sensor?

I'm running it in auto, feed rate at 3.5. I tried it at 5 and that didn't help.

The flame right now is constant, it will not stop at any point but the problem will persist. Temp will reach about 150F then go back down to 135F, the flames are high and will cycle between those temps.

Thanks for trying to help.

 

[cce3]

Cleaned it again today. Noticed that the intake from the outside of the house got some frost.

It got worse.

It used to be high flames, low temp. Now, it's low flame, low temp.
What the heck is going on?

Edit: The little auger door was not seated properly. Flame is high now.
I got it! Cleaned the darn thing from head to toe and she's back to 180 F. I'm thinking the frost that's blocking the intake caused the low heat. I thought flame wasn't lazy so I wasn't focused on the draft.

 

[rickwai]

Leave a gap between your outside air tube and stove hook up. That way if there is a problem it can breath. Glad it is running good now. The door under the burn pot was loose?

 

[cce3]

It's the little door to clean the fines by the auger under the hopper.