Stove Keeps Blowing Draft Fan Fuse...

[GreenMtnLt]

I have owned a USSC American Harvest 6039 for quite awhile. It has been a great stove up until recently.

Last year, mid heating season the stove blew the draft fan fuse (Err 7.) Prior research led me to believe that the draft fan was either jammed or dirty, or dead. I removed it, cleaned it and brought it to a professional electric motor repair shop for testing. The fan tested out fine. I reinstalled the fan, replaced the fuse and heated for the rest of the winter without issue.

Now today, I fired up the stove for the first time. It ran flawlessly for about an hour when it popped the draft fan fuse again. I knew everything was clean as it was thoroughly cleaned at the end of last season. I had a spare fuse, threw it in the circuit board, plugged the stove back in, and it immediately blew the new fuse.

I really would like to find out why it keeps blowing this fuse. It has become a real PITA.

Does anyone have any insight or solutions to this problem? Your help is greatly appreciated.

Justin.

 

[johninwi]

i'd look at the wiring for the motor, you may find a nick in the insultion, guessing the wires rubbed agienst some thing over the years and when you removed and tested the motor the short was removed, after running for a few months the wires moved back to where they shorted again, but just a guess.

 

[GreenMtnLt]

I did check the wires, and ironically enough I found one of the leads to the motor had rubbed agaisnt the exhaust tunnel. While the wire's insulation did not melt through to the wire, I am hoping that was the issue. A buddy of mine who is good with electronics is replacing the leads for me. Hopefully this will cure the problem. Thanks for the insight johninwi!

 

[daffonce]

Popping fuses means you either have a short after the fuse (leads to the motor or internal to the motor) or the motor for some reason is drawing high current. Replacing the leads is a good idea but id think about buying a spare motor just in case. Cause you know when chit goes wrong, at the most inopertune time.

 

[silverfox103]

An immediate blowing of a fuse, means there is a "dead short" to ground, which is exactly what your friend found. Hope that cures the problem.

Tom C.

 

[GreenMtnLt]

So the fan bench tested fine...replaced fuse and attempted start up cycle without the fan connected, and the same fuse blew immediately once again. Is there a way for me to bench test the circuit board? Buddy and I are going to start checking every wire in the meantime...new circuit board is $500...not sure if stove is worth that at this point...

 

[daffonce]

Are the leads diconnected from the board? If so it seems like their is likely an internal board short. No easy fix there. Any chance the board is touching the metal frame? The frame is likely grounded. If a solder junction is touching the frame that is a short. Maybe remove board look at back of it and and the frame look for signs of grounding. Could remove board apply power to it and turn it on see if fuse blows then. If it does you maybe out of luck. You could tap power from fuse input side (solder a wire onto it or connect a wire to input) and then fuse that link and run that to the fan. Basically pull power for fan out of board before it goes through the board where tbe short is.

 

[Harvey Schneider]

Are the leads diconnected from the board? If so it seems like their is likely an internal board short. No easy fix there. Any chance the board is touching the metal frame? The frame is likely grounded. If a solder junction is touching the frame that is a short. Maybe remove board look at back of it and and the frame look for signs of grounding. Could remove board apply power to it and turn it on see if fuse blows then. If it does you maybe out of luck. You could tap power from fuse input side (solder a wire onto it or connect a wire to input) and then fuse that link and run that to the fan. Basically pull power for fan out of board before it goes through the board where tbe short is.

It is also possible that there is an intermittent short to ground inside the motor. That wouldn't show up in bench testing unless you were looking for it.
With the motor isolated from the stove, check for line Voltage on the motor frame with respect to neutral or ground.

 

[daffonce]

He ran it wo fan hooked up hence my thinking in board.

 

[Harvey Schneider]

He ran it wo fan hooked up hence my thinking in board.

It wasn't clear that the stove was plugged in when the fan was tested. If it wasn't, there would have been no path to ground for the short. A winding short to case is an easy problem to miss unless you look for it.