Whitfield Profile-30 (Lennox branded) blows fuse on circuit board

[bandsdean]

This one has me stumped and after 10 seasons of ownership and self repair of, auger motors, a room blowers, and crappy pellet dealings I find myself needing to reach out for help. My circuit board fuse keeps blowing as soon as I call for heat. With the pellet stove switched on and no call for heat, the lights work as normal. As soon as I call for heat, the 5 amp fuse blows. Replaced the fuse twice with the same results. I see no burnt pins, diodes, capacitors, resistors or breaks on the board. I suspect a bad board. Anyone else have this issue? I was just going to bite the bullet and buy a new board and send the old one out for repair for a spare.

 

[bandsdean]

Here is a video of what happens....

 

[Mt Bob]

Unplug ignitor and see if it blows fuse.

 

[bandsdean]

Good idea. How about I unplug the 3 motors too and then plug one in at a time? Need to get some more fuses. Will advise on the results.

 

[Mt Bob]

Good idea. How about I unplug the 3 motors too and then plug one in at a time? Need to get some more fuses. Will advise on the results.

Yep go for it.

 

[Mt Bob]

Actually,the more I think about it,the combustion motor starts first in most stoves,but try everything.Before wasting fuses,take stove apart,follow all wires and look for one rubbed through insulation.May find small burn mark.

 

[Stovensen]

I suspect a bad board. I was just going to bite the bullet and buy a new board and send the old one out for repair for a spare.

We do not know yet if it is a bad board. It could also be damaged wiring in the auger motor loop making a short to ground or... it could be shorted/melted windings in the auger motor. This would explain why the 5 A fuse ( fast-blo ) blows immediately when the stove calls for heat.
Bandsdean, do you have an ohmmeter? If so, I suggest the following:
First, take a look at the Profile wiring diagram below. Between PIN 7 and 15 in the molex plug ( two brown wires ) you have access to test the entire auger motor loop ( including the safety devices ).

Unplug the stove and next unplug the 16 pin molex connector. The testing is on the disconnected male part with the two brown wires on PIN 7 and 15.
If your ohmmeter has a manual range knob, set it to the lowest range.
All the safeties are N/C ( normally closed ), so what we test on pin 7 and 15 is the copper resistance of the field coil in the auger motor. This should be 18 Ohm ( +/- 2 Ohm ).
Next we want to check if the wiring loop to the auger motor has any shortings to ground, so now you connect one of the test leads from the ohmmeter to stove ground... there should be one on the convection motor ( green/yellow wire ). The other test lead you connect to PINs 7 and 15 in the molex plug, one at a time. The reading should be infinite Ohms, but if not, the wiring is damaged, making connection/shorting to ground.
@BobBare: The igniter should have a separate 6 A fuse on its own in-line with the wiring.

 

[bandsdean]

Sorry I haven't gotten back to you all. OK. With the unit unplugged, I unplugged both blowers, and the ignitor. I plugged it back in (no call for heat yet) and turned it on (still no call for heat). I plugged in the room blower, it turned on as normal, the same for the convection blower. I suspect it was on cool down mode as the blowers turned on. I left the ignitor unplugged and called for heat and the fuse blew. Like a dummy I didn't unplug the auger so I'll have to go back and do that and do the trouble shooting above. I have 3 more fuses so we'll see how it goes. Will update with the results. Weather's been warm so I haven't needed the stove as of late.

 

[bandsdean]

Bad windings in the auger motor. Ordered new one today. Once installed, will update. Thanks a lot.

 

[bandsdean]

Replaced auger. Ops check good. Ok for service. Thanks for all the help!

 

[Lake Girl]

Glad to hear you are up and running. Almost time for that final clean until next year that is.

 

[Bioburner]

Glad to hear you are up and running. Almost time for that final clean until next year that is.

We can all hope!

 

[Don2222]

Hello

If you put an inline fuse holder from Home Depot on the auger motor like the one in the pics here that I did and it happens again, you will know.
https://www.hearth.com/talk/threads...the-board-fuse-and-power.126865/#post-1705653

 

[bandsdean]

Great idea for the in line fuse. Thanks for the tip.