Harmon XXV replaced combustion blower now it wont shut off

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Dave22

New Member
Apr 8, 2018
7
United States
Hello,
I have an older Harmon XXV (chain drive) and the combustion blower failed the other day. I purchased a new one from a local dealer (OEM) newer model (no rear fan blade). I have it installed and working but it doesn't shut off. it continues to run even when the stove is cool or the dial is set to off.
I am not getting any status error code (blinking lights). I have cleaned everything and tried disconnecting the ESP to make sure the status light would register an error, and it did.

Any help or suggestion will be greatly appreciated.

Thank you
 
A few things can cause your combustion blower to run non stop. Incorrect dipswitch settings, a vacuum switch not staying closed because of a clog or leak somewhere and I’ve also seen them do this after a power surge if they board took a hit in that relay. I’d start out by making sure you didn’t break some crud loose that’s clogging it up while replacing the blower and I’d also make sure your blower is mounted tight.
 
A few things can cause your combustion blower to run non stop. Incorrect dipswitch settings, a vacuum switch not staying closed because of a clog or leak somewhere and I’ve also seen them do this after a power surge if they board took a hit in that relay. I’d start out by making sure you didn’t break some crud loose that’s clogging it up while replacing the blower and I’d also make sure your blower is mounted tight.

Thank you for your reply.
When you say "crud loose that’s clogging it up" Are you referring to the pressure switch?

I wonder where this motor is a newer version (higher amp rating) if a dip switch needs to be set differently.
I have double check and removed and reinstalled the blower to make sure it is in tight. I read in the manual that the armature needs to point up. I'm not sure why that is but I can try that.
Do you know if I disconnect the pressure switch and jump it can I test it that way?

Thanks again
 
Yes the pressure switch can be jumped to tell you if that’s your issue. The change in dipswitch settings has nothing to do with what blower you have. here’s the dipswitch settings for the new boards. I’d have to see your board to kno if it’s the old style
 

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Yes the pressure switch can be jumped to tell you if that’s your issue. The change in dipswitch settings has nothing to do with what blower you have. here’s the dipswitch settings for the new boards. I’d have to see your board to kno if it’s the old style
Thank again for your help. I tried to unplug the pressure switch (both leads) and with the stove temp dial set to off, the room temp dial set to 55 the lowest setting. I plugged in the stove and the fan came on. the only light on the panel is the power light. I shut the stove down and jumped the pressure switch leads and plugged the stove back in and the fan came on again. the only light is still the power light.

I attached pictures of the circuit board and a close up of the dip switch
.Harmon XXV replaced combustion blower now it wont shut offHarmon XXV replaced combustion blower now it wont shut offHarmon XXV replaced combustion blower now it wont shut off
 
There’s something on thos boards that blows and causes it to run nonstop. Only solution I know is a new board.
 
Could a bad ESP cause this ? I wonder if unplugging it from the board would give an answer.. Sorry,
Re-read original post and already tried unplugging ESP..
 
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Does auger turn when you put into test mode? If it does not then it is a vac switch is not closing
 
then you have a esp or board issue. If you get a esp you can unplug old one and plug new one in before installing to verify. Also play with the knob and see what happens. I have seen where the knob is worn out and there is only a small spot in the middle where it will shut off. Is the comb blower light illuminated even when knob is off and stove cold?
 
then you have a esp or board issue. If you get a esp you can unplug old one and plug new one in before installing to verify. Also play with the knob and see what happens. I have seen where the knob is worn out and there is only a small spot in the middle where it will shut off. Is the comb blower light illuminated even when knob is off and stove cold?


The lights come on while the stove is running but after temp is met or if the stove is shut off all lights except power go out. The blower just keeps running unless stove is unplugged.
I ordered a new red esp and board ver E last night. ESP was on sale and I found a 15% off coupon so I figured that was a sign to just replace both. The parts will be a week or so getting here, but I'll post after I have them installed to let you know how it went.
Thanks to all for your help
 
the new board and ESP came in on Monday. I had a busy week but was able to get the board in stalled. A huge Thank you to
Overfireinthehole for the dip switch setting I wouldn't have been able to get the board working without those. That got the stove working. I tried to install the new ESP, But the red wired version is about a 16th of an inch larger in diameter than the black wired version. The new one will not fit in the port hole. I didn't have time to spend on it but hope this weekend I can file that hole a little large to get the new unit in place.

Thanks to everyone for your help, Heat is nice!