Coleman 8655-0766

[psalmx]

So I have this relic of a furnace that runs surprisingly well, except today ofcourse. Today is the first time I have fired this thing up. I replaced the thermostat as the previous home owners said the furnace would only run with the furnace on 72. I kut the pilot and it fired up fine heats well except it continues to run after it has reached the set temp. Even turning the thermostat off and disconnecting it it still continues to heat. I also noticed the draft motor runs constantly. The only way to shut the burner down is to kill the breaker. I have noticed this furnace has alot of newer parts, Blower motor, gas valve, and the transformer look newer. What could cause this?Also the wires on the old thermostat were in no way labled. It is a two wire heat only system but I'm trying to use a standard honeywell programmable thermostat. I have the wires hooked to RH and W. Is that right?

[Robert]

Some t-stats will not work with a 2 wire system, yours may be one of those.

Hard to say if that is the problem without being there though.


Thanks,
Robert

[psalmx]

Thanks for the reply Robert. I luckily have a wiring diagram and I'm gonna go through it this weekend. I have a feeling its that realy but I'm gonna try disconnecting a wire from the gas valve and see if that shuts it down.

[psalmx]

good news is I traced it down to a bad relay. Replaced it and all is well.

[Robert]

That's great, thanks for update.


Take care and best wishes,
Robert