Harman P61 problem

[rsoucy]

I have a P61 that I have used extensively for about 6 years with no problems. I do my own maintenance, only cleaning so far. I cleaned the stove this fall for the winter season. It started right up and worked fine for about 3 days. I turned the thermostat down a week ago since we have had some nice weather here on Cape Cod. I filled the hopper and dialed up the thermostat yesterday and nada. I am getting nothing - no auger, no combustion blower, nothing. I am getting power to the unit since all leds (combustion, circulation and feed, power and status) but again, nothing. I emptied the hopper and cleaned out the auger tube as best I could without disassembling and the lack of response is the same. I have tried it in test, room and stove mode and the response is the same - nothing. The leds light up but there is no system response. I have listened closely for any sound of activation while tuning it on and off in the event the auger or fan is bound, but do not hear anything.

Any ideas on where to start debug? Any suggestions would be greatly appreciated as I am looking at a $200 up front charge for the first hour of service if I need to resort to calling someone in.

BTW, I am really happy with the stove. 6 years of hard use as a primary heat source and I have not had a single problem with the stove (knock on wood). We own two other P61s in other homes we own and they likewise have worked flawlessly for years with no maintenance other than cleaning.

Thanks in advance for any suggestions.

Rick

 

[Delta-T]

give the combustion blower a spin by hand (behind ash pan). it might be stuck. if it doesn't go, nothing else will go.

 

[Delta-T]

make sure to unplug it before you stick your hand in there too

 

[rsoucy]

Thanks for the response, and yes, I did remember to unplug prior to sticking my hand in. The combustion fan is and was free - but still not running.

I have done some further cleaning, which it did not really need. I cleaned and inspected the esp probe and probe wiring. I checked the 3A fuse on the board and it is fine. Still the same symptoms - all leds light (power, status, combustion, distribution and feed), and additionally the status light is lit constantly, yet neither the combustion blower nor the auger run in any mode (stove, room or test). When it is in test mode I can get the distribution blower to run, but neither the combustion blower nor auger run in test mode.

Is it true that the combustion motor must begin running before the auger will engage? If so I suspect there is a clue in the fact that the combustion blower led lights (indicating power is getting to the combustion blower) yet the blower does not run. It would appear to be a problem with the combustion blower and since it is not fused in line would indicate the blower is probably dead? The lack of combustion motor would explain the auger not running. Does this make sense?

Rick

 

[rayttt]

Yeah.. If no combustion going..no vacuum..no auger feed.
You can test the blower by disconnecting it from the wires going to the pcb and jump right to the line cord coming in.

 

[Bob Sorjanen]

maybe a dumb suggestion but have you tried without the thermostat hooked up?

 

[Lousyweather]

nah.....disconnect the leads to the combustion fan, make a pigtail, hook the fan up directly to line voltage and see if it runs....if it doesn't run, its the fan, if it does, its something else we can pursue....

 

[rsoucy]

maybe a dumb suggestion but have you tried without the thermostat hooked up?

It is a good suggestion but that is basically what the "stove" mode and "test" mode do on the P61. "stove" mode uses an internal sensor different than the external room temp sensor. Something could be broken in that area to cause them both to go out, but the "test" mode basically just forces the stove to run (I believe) independent of the temp sensors. There could be some condition that causes an override but...

I am getting ready to check the fan by hardwiring it, and am also going to check to insure I am getting power at the terminal on the fan with a DMM which should eliminate any and all potential sensor issues.

I suspect the fan.

Thanks again for responding. I just fortunately stumbled on this site. It seems to have a very high signal to noise ratio - lots of knowledge and helpful people.

Rick

 

[imacman]

....I am getting ready to check the fan by hardwiring it....

That was my next suggestion. Do yourself a favor....make a power test cord out of an old lamp cord. Comes in very handy for testing blower & auger motors.

As always, be sure to INSULATE the leads.

 

[rsoucy]

The saga continues. It would appear as expected that the combustion motor is dead. I hot wired directly to the terminals and nothing. What is interesting is that while checking the power to the motor I think I have discovered that the power to the motor is never interrupted. Regardless if I have the stove set to "room" mode with the thermostat set to 50 degrees (it is 72 in the room at the moment), or in "stove" mode, there is always 120V AC power to the motor leads coming off the board. I would assume this is not normal and there should only be power to the combustion motor when there is a call, which certainly is not the case with the thermostat set to 50 degrees in a 72 degree room? It could also be that the thermocouple room sensor is messed up, but I believe that in "stove" mode with the thermostat turned down all the way it should be off also.

It appears that the board has power switches rather than relays. Does anyone know if these are easily replaceable or am I looking at doing pcb rework to attempt this? Could I be looking at a new board in addition to a new motor?

Any thoughts?

Again, thanks in advance for any advice.

Rick

 

[Lousyweather]

you'd be partially wrong.....while the stove is running, there is ALWAYS power to the combustion blower.....not always to the distribution blower or the feeder. Dis blower is controlled by the ESP and the potentiometer setting (L thru H). The only time the comb blower isn't powered is when the stove is in shutdown and cool....in its "wait" state, checking the room temp, waiting for it to get low enough to re-ignite. But under operating conditions the combustion blower will always run if there is a fire, its lighting, or its in TEST mode. If you hardwired the fan and it didn't start, its failed. get a new one.

 

[Lousyweather]

oh, no, replace the fan first......you likely don't need a new board.

 

[rsoucy]

oh, no, replace the fan first......you likely don't need a new board.

Thanks Lousyweather, I do intend to replace the motor. I am getting ready to order one tonight. I am currently wrestling with the fan blade attempting to get the collar set screw loosened.

I still have a question that I would appreciate clarified. I guess I should note that this is actually a p61a with auto ignition. When I power the stove up initially, no fire, stone cold, and I have it in "room temp" mode with the thermostat set to 50 degrees and the room temp is 72 degrees why should I expect the combustion motor to run? There is no call for heat so I would expect the stove would sit in idle mode until the temp drops below 50 degrees in the room, or I turn the thermostat above the room temp to create a call for heat. At that time I would expect the combustion blower to start up, create a vacuum, engage the auger motor and the igniter and voila, heat. I have not paid much attention but again, unless there is an initial call for heat when I plug it in I would expect it to just sit there.

Wrong?

 

[P38X2]

I believe you must have the toggle in the manual ignite setting if you're experiencing that scenario. Switch it to auto and the combustion motor should turn off. The combustion motor is running in anticipation of you lighting it. Don't tease it like that

 

[Harman Lover 007]

Sounds like you are on the right track....but to be "sure" did you make a pigtail and power the motor from an outlet or did you get the power from the stove? Gonna get cold here next week so you'll want to get that motor ASAP.

 

[rsoucy]

I believe you must have the toggle in the manual ignite setting if you're experiencing that scenario. Switch it to auto and the combustion motor should turn off. The combustion motor is running in anticipation of you lighting it. Don't tease it like that

Well, that is why I believe I have a problem. It behaves the same whether I have it in manual ignite mode or auto. As a result of your suggestion I am going to re-check it today, but I did conciously toggle and try it both ways. I love my P61 and would never tease it

BTW, I am going to just istall the new motor and ignore this other potential problem and hope the new motor fixes everything, but I suspect the new combustion motor is going to run continuously and I am going to be looking at the next problem.

 

[rsoucy]

Sounds like you are on the right track....but to be "sure" did you make a pigtail and power the motor from an outlet or did you get the power from the stove? Gonna get cold here next week so you'll want to get that motor ASAP.

I made a pigtail power chord and connected directly to the motor. I am absolutely certain the motor is dead.

I was going to order the motor last night online, but figured I would wait till this morning to talk to a live person and insure prompt shipping and expedited delivery. The OEM motor seems to be in stock in a couple different places so I would hope to have it late this week, or early next week at the latest. It shouldn't take more than a couple hours to get it put back together and running.

I will keep my fingers crossed that the control board is functioning properly and that the symptoms I am seeing are some abberation due to my deficient debug skills.

Thanks for your input.

 

[rayttt]

How old is your P61?
Would it be covered by warranty?

 

[rsoucy]

How old is your P61?
Would it be covered by warranty?

It is six years old and out of warranty so it looks like I am footing the bill. At 6 years of heavy use I cannot complain. It has been an extremelyl reliable workhorse, so to replace a $150 motor is not a big deal. The control board will hurt though if it comes to that.

 

[rayttt]

Just FYI you can get a replacement cheaper than $150 in http://www.grainger.com/Grainger/wwg/start.shtml

 

[Lousyweather]

Just FYI you can get a replacement cheaper than $150 in http://www.grainger.com/Grainger/wwg/start.shtml

just don't destroy the interior fan in trying to get it off.....or you'll need one of those as well, and you wont find that at Graingers.......they can get brittle, and fins can break off. We give it a shot when replacing them, but VERY OFTEN, its hard to get them off, there's a trick or two to try, but maybe half the time we end up cutting the shaft and replacing both.....time is money, and it generally doesn't pay to mess with something for a long time when the tech has other stops to make.....

 

[rsoucy]

just don't destroy the interior fan in trying to get it off.....or you'll need one of those as well, and you wont find that at Graingers.......they can get brittle, and fins can break off. We give it a shot when replacing them, but VERY OFTEN, its hard to get them off, there's a trick or two to try, but maybe half the time we end up cutting the shaft and replacing both.....time is money, and it generally doesn't pay to mess with something for a long time when the tech has other stops to make.....

Yeah, I have already run into that problem and am working on it. I put PB Blaster on it last night and again this morning. I am going to give it go shortly and if it is still stuck I am going to clean up the flammables and try some heat on that hub with an extinguisher nearby of course. I may just replace the fan. I believe I saw one for $12 somewhere. It would seem that insuring the fan is well balanced could be important to bearing and overall fan life?

If I cannot get the set screw loosened and have to resort to cutting the shaft what is the best tool to go after it with? Is that shaft hardened? I can't visualize getting anything in there but a reciprocating saw or by hand a hacksaw with no frame (not sure what they are called - looks like a keyhole saw handle with a hacksaw blade). Will this do it or do you have better ideas?

Thanks again for following along here. I am learning a bunch about my stove that is going to serve me well down the road as it gets older.

Rick

 

[Lousyweather]

Yeah, I have already run into that problem and am working on it. I put PB Blaster on it last night and again this morning. I am going to give it go shortly and if it is still stuck I am going to clean up the flammables and try some heat on that hub with an extinguisher nearby of course. I may just replace the fan. I believe I saw one for $12 somewhere. It would seem that insuring the fan is well balanced could be important to bearing and overall fan life?

If I cannot get the set screw loosened and have to resort to cutting the shaft what is the best tool to go after it with? Is that shaft hardened? I can't visualize getting anything in there but a reciprocating saw or by hand a hacksaw with no frame (not sure what they are called - looks like a keyhole saw handle with a hacksaw blade). Will this do it or do you have better ideas?

you can sawzall the shaft, just make sure you don't cut the lugs which hold the motor in place (there's 3).......also, you can use a Dremel with a cutting wheel as well....

yea, the more balanced the wheel is the better....and if it gets dirty (ie: never cleaned), even a perfectly balanced wheel will go off-balance....

oh, and use the right blade......different blades move different amounts of air......

Im sure you will persevere, Rick!

now, lol, imagine if you replace it and it STILL doesn't work!!?
heat might work, what the heck.....give it a try.......but now you can see why we don't spend a lot of time messing with them......just so much easier to cut the shaft off the bad motor and replace....

Thanks again for following along here. I am learning a bunch about my stove that is going to serve me well down the road as it gets older.

Rick

 

[P38X2]

Is there a high temp anti sieze that could be used on that set screw for preventative measures?

 

[Bioburner]

Catapillar has a very good antiseize. I don't know how small of container you can get it in. Loctite makes a very good product as well. I have a pint can with a brush. Great to have for hinge pins and bolts. A must have for spark plugs and glow plugs etc.