1997 Harman P38 Died

[Bobhjr]

My stove just quit. It was pretty clean, but I re-cleaned it and pulled the probe and wiped it off. I'm getting power to and through the fuse. Orig board with just 2 knobs, no lights. The only thing doing anything is the small combustion? motor on the back bottom. It's turning slow when I plug the stove in.
Thanks,
Bob H.

 

[P38X2]

Maybe time for a new combustion blower. Start there, anyway. How much use has that stove seen? That's fairly incredible if that's the orig motor.

 

[Bobhjr]

Maybe time for a new combustion blower. Start there, anyway. How much use has that stove seen? That's fairly incredible if that's the orig motor.

I bought it in 2009, and I believe everything had been replaced that year. I also replaced the noisy blower motor last year. Isn't there any tests I can do before I just start replacing parts?

 

[P38X2]

Yes, but let's let someone with a bit more Harman electrical experience chime in.

When you turn the stove on, all motors should turn for a bit. Is this happening?...or is it just the slowly turning combustion motor?

 

[Bobhjr]

Yes, but let's let someone with a bit more Harman electrical experience chime in.

When you turn the stove on, all motors should turn for a bit. Is this happening?...or is it just the slowly turning combustion motor?

When I plug the stove in, the little combustion motor turns. When I turn up the feed and heat knobs, nothing happens.

 

[Lousyweather]

pigtail the combustion blower, directly to line voltage......does it turn fast, no variance? if not its good.

then look at your vac switch.....if you suck lightly on the silicone line, do you get continuity on a multimeter? if you do, its good.

only thing left is the board.

 

[Bobhjr]

pigtail the combustion blower, directly to line voltage......does it turn fast, no variance? if not its good.

then look at your vac switch.....if you suck lightly on the silicone line, do you get continuity on a multimeter? if you do, its good.

only thing left is the board.

I don't see a vac switch or silicone line

 

[Lousyweather]

I don't see a vac switch or silicone line

look harder

 

[Bobhjr]

look harder

I have an old P38. Can't find a manual anywhere. I see in the P38+ manual it's above the intake vent. I look again.

 

[rickwai]

To get all motors to start you go from off to turbo to off then to on (2-3). This will put stove in test mode and start motors on high. If comb. fan is running slow it will not make the vac switch and auger will not start. Dist blower should come on. If you push a sewing pin into white and black wire of comb motor you can check voltage without tearing into wiring harness. Voltage should be between 100-120 volts I think. If voltage is good motor is shot. Fan blade set screw can be tought o get broke loose. try it w/ allen wrench, if it does not budge dont strip it. Heat the collar that the set screw is threaded into with a plumbers torch for maybe 30 seconds then try, if still wont break loose heat again. This almost always works. I had to do this twice this week to change comb motors on Harmans. If voltage is real low board is bad. I think the 2 knob is obsolete and you have to replace it w/ a retro kit to convert to a 3 knob board. The board that is used on a p61 w/out auto ignition.

 

[rayttt]

I don't see a vac switch or silicone line

The only switch not on the pcboard is the one on the Air Input...if you can push in to the plate that covers the air intake...thats the switch that gets engaged when there is an actual draft from the heat.
There isn't any vacuum line in my P38...which is much newer (2008). I dont know if older ones would have one.


You can take the line cord that comes into the stove and unplug it from the wires that its connected too..and connect them directly to the Combustion blower and it should spin at a steady high speed rate. If not the fan is bad.

 

[rayttt]

If you end up needing a new control board..Ive seen used P38 boards of the old style via googling...
Or you can get a new board upgrade kit..which has a new wiring harness and wiring diagram.
I got one for $225.00.

 

[rickwai]

I have never seen a harman w/out a vac switch....

 

[Bobhjr]

stove

I have never seen a harman w/out a vac switch....

Testing complete. I ran power to distribution, combustion and feed motors. All come on. Hooked feed motor back up to vacuum switch and ran power to feed motor and combustion motors. When combustion motor comes up to speed (couple of seconds), the vac sw closes and the feed motor comes on. The only thing left seems to be the circuit board. Fuse is good. Not sure if the esp probe plays a part in this. It is clean.

 

[P38X2]

Well you seem to be competent with electronics. Rather than repairing or purchasing a NOS board, I suggest getting the updated retrofit kit. You may REALLY like having the "Room Temp" feature.

I'm not sure if the ESP could still be the issue, but I bet it's not. If you have a multimeter, it can be tested. Just don't ask me how.

 

[rayttt]

Testing complete. I ran power to distribution, combustion and feed motors. All come on. Hooked feed motor back up to vacuum switch and ran power to feed motor and combustion motors. When combustion motor comes up to speed (couple of seconds), the vac sw closes and the feed motor comes on. The only thing left seems to be the circuit board. Fuse is good. Not sure if the esp probe plays a part in this. It is clean.

I'm not positive But I seem to recall someone having a harman that didn't start and it turned out to be the ESP, not sure mindya but a search may turn up more.

An ESP Probe is around 50 bucks I believe...and a board is $225+
And I would recommend the Board upgrade, if you need a new board.
You could try for the ESP and if still not working then get the PCB.

 

[Bobhjr]

I'm not positive But I seem to recall someone having a harman that didn't start and it turned out to be the ESP, not sure mindya but a search may turn up more.

An ESP Probe is around 50 bucks I believe...and a board is $225+
And I would recommend the Board upgrade, if you need a new board.
You could try for the ESP and if still not working then get the PCB.

Board upgrade complete. Working but distribution fan stays on and prob light blinking 3 times. Book says it's the ESP probe.

 

[rayttt]

Board upgrade complete. Working but distribution fan stays on and prob light blinking 3 times. Book says it's the ESP probe.

If your ESP and exhaust are clean ..you may need a new esp

 

[rayttt]

On the new board there is a dipswitch...most switchs off.

Depending on which ESP you have Dipswitch #5 may need switching..one position is ESP with Red wires..and the other position if for an esp with Black wires.

 

[Maly96]

Hello,
Newbie to the forum.
I also installed a new board and probe today. I'm having an issue. The stove runs through the test setting fine but when I turn it to run on stove or room temp, only the stoves combustion motor works and the auger and blower stop. Thus the stove goes out. My new esp is the black wire style so the #5 dip is off. Any suggestions would be greatly appreciated.

Thank you
Maly96

 

[Bioburner]

Have you made sure the vacuum switch line is clean and clear? Without a vacuum in the fire chamber the stove will not complete the circuit to run the auger.

 

[twodogs02]

Hello,
Newbie to the forum.
I also installed a new board and probe today. I'm having an issue. The stove runs through the test setting fine but when I turn it to run on stove or room temp, only the stoves combustion motor works and the auger and blower stop. Thus the stove goes out. My new esp is the black wire style so the #5 dip is off. Any suggestions would be greatly appreciated.

Thank you
Maly96

I recommend starting a new thread, high jacking this one might not get the exposure you need.