Coleman Evcon DGAT075BDF blower cycling on and off

[mikea]

Coleman DGAT075BDF blower keeps cycling on and off with the thermostat set in the off position. Will come on for a few minutes then switch off then come right back on. Will repeat this regularly in some varing pattern or time on and off. Repairman came today and said replace the Integrated Control. I think he was guessing, said he never heard of the problem. The burner does not come on when this happens...shouldn't since thermostat id n off position. Please, any help would be appreciated.
Mike

[Robert]

Turn power to furnace OFF, disconnect the white wire and green if applicable from the t-stat, return power and see if it happens again.


If it does, would need to check for a direct short powering unit/blower up intermittantly.


Thanks for inquiring,
Robert

[mikea]

Robert,

Thanks for the reply, I will try disconecting the wires.

I checked your parts list for a new control board in case I have to replace it. My control board on my DGAT075BDF is marked 7990-320. Looking at your part list, the 7990-320 does not look like mine. Mine actually looks like the 7990-319 that you show on your parts list. Mine is green with a 3 amp fuse in the upper left.

Should I get the 319 which looks like mine or the 320 which mine does not look like even though mine has 320 stamped on it?

Thanks for your help, and hey, when do you sleep?

Mike in IOWA

[Robert]

Hi Mike,

When do I sleep, good question, LOL. . Due to health issues, sleep is not as often or prolonged as I'd like, so if I have to be awake and up, figure might as well answer questions if there are any.


Let me check on the board. They change colors and looks, so most likely need to stay with p/n, but I'll check and see and check back tonight for reply to what I suggested.



Thanks

[Robert]

Hi,

I deleted two previous posts by danpa due to error in the order of parts numbers and what replaced what.


Also because there is no way to know what is causing this without first doing extensive testing as was advised to danpa in his other post in this forum.


These HVAC forums are for seeking help and asking questions, but not for attempts at troubleshooting a unit without the sites firsthand knowledge of experience to do so.


The wires themselves could very well be at fault due to a direct short, replacing a costly board to discover it was a section of wire is something we try to avoid.


Sometimes, my not giving direct or complete answer or divulging certain info is actually for the posters best interest to try and ensure a proper and complete diagnosis.


Problems stated by danpa have occurred and may be problem of this one and his or may not be either.


Thanks,
Robert