Need advice - Fixing Harman P-68

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

ScottyDaug

Member
Dec 26, 2010
75
Maine
I have a friend who has a Harman P-68. It was working fine last season, but this season nothing seems too work, no auger, no blower. I tried to diagnose it, but came away stumped. The auger and blower light comes on, but nothing operates. I checked the vacuum switch hose, and it appears to be intact. I am going to take another go at fixing it, and I am looking for advice. I may be mistaken, but if memory serves me correct the power light was not lit even though the auger, and blower lights where. I would greatly appreciate any advice/input.

Thank You,

Scott
 
I have a friend who has a Harman P-68. It was working fine last season, but this season nothing seems too work, no auger, no blower. I tried to diagnose it, but came away stumped. The auger and blower light comes on, but nothing operates. I checked the vacuum switch hose, and it appears to be intact. I am going to take another go at fixing it, and I am looking for advice. I may be mistaken, but if memory serves me correct the power light was not lit even though the auger, and blower lights where. I would greatly appreciate any advice/input.

Thank You,

Scott
Are the power and status LED's lit? Unplug the stove for one minute and plug it back in. What does it do when you plug it in? Does the combustion blower run for a second or two? There is a small glass fuse on the control board (back side) check that. Two small Philips screws to remove control board. Get back to us....
 
When I unplugged it, and plugged it back in, it was silent, no combustion blower.
 
Any status lights on control? Have you checked the fuse on the back of the control board?
 
Blower may be dead. No blower no auger. Also may be jammed with material check to make sure the fan spins freely. Hot wire blower to test.
 
Blower may be dead. No blower no auger. Also may be jammed with material check to make sure the fan spins freely. Hot wire blower to test.
All motors should activate when put in test mode.
 
I have not checked the fuse yet, I figured if it was blown there would be no lights lit?
 
Correct there is only one fuse and if nothing comes on when the stove is turned on then more than likely they will not run in test.
 
If you do put in test the distribution blower should come on.
 
Only if the combustion motor works or you bypass the switch.
 
Only if the combustion motor works or you bypass the switch.
Your right. Exhaust motor comes on then if vac switch is satisfied then it completes the feed circuit. Mind is not with it today as trying to keep deer hunters from shooting the horse and dogs, house.
 
UPDATE: I went back today to take another attempt at fixing it, without success. I thoroughly cleaned the stove, tried bypassing the vacuum switch, but still nothing. I am starting to suspect the control board, but I don't have another to try. When it's plugged in the power light, and the auger light doesn't come on, but the igniter, distribution, and combustion blower lights do. Sometimes the status light will come on, and it will be solid. I thought it strange that the power light doesn't come on, unless the bulb is burnt out? The stove remains completely silent when plugged in, and regardless of what mode is selected, no blowers, no auger, complete silence. I checked the fuse, and it is fine. I am stumped. I would greatly appreciate any input. I have attached a photo of the control board lights, sorry for the poor camera phone pic.
y5y3ymyd.jpg
 
Last edited:
Oh boy...that doesn't look good. There should be a glass fuse on the back side of the board. Check it. While you have the board out check it to see if it has any burn marks....
 
I checked the fuse, and it appeared to be completely intact. I didn't see any burn marks. The owner has it plugged directly into an extension cord without a surge protector. The stove is in a basement that only has one outlet. The extension cord is a heavier one that is around 100' long. The owner ran the stove last season without issue.
 
Don't know how handy you are but you need to get a decent multi meter and start testing where you have power and where you don't. Those lights are leds, I doubt they are burned out. I'm with you, though...very suspicious of the control board. Is it possible the stove took a power surge in the off season (lightning strike?)
 
A power surge is my suspicion, I did poke around some with the multimeter. There was power at the vacuum switch but not at the blowers, or auger.
 
If the stove was left plugged in on the off season with out a surge protector it could be a control board. if you have the stove plugged in and have power, with the stove in the off position and turn the feed to test mode you should get 120V to the combustion and dist. blower. if the fuse is good and power is not present at both or either one of the motors then it needs a new board, there are no safety switches or board logic that in that situation should prevent power from being sent to the blower motors. if the board ends up being bad he can get a UPS at the same time he gets the new board. that will protect the board and when you get the ups Harman recommends when the power goes out the stove will automatically shut down properly and not get smoke in the house...
 
Any time the power is off to the stove and is then repowered it should run the exhaust fan for a short time. I would make a pig tail power cord to give the exhaust fan direct power to positively rule out the fans. Wont hurt and not very expensive t make one up.
 
If the stove is unplugged and plugged in again the exhaust fan does not come on. It looks like things point to the control board. I'm a little worried about taking the chance with such an expensive purchase if it turns out not to be the culprit.
 
I really appreciate all the help/input.
 
Status
Not open for further replies.