Originally Posted by 4getful2
I have a '96 goodman janitrol mod#gmpn060-3
the problem is that it will cycle normally for an hour , maybe two, sometimes overnight ,but when it get to the end of it's heating cycle and the air starts to cool down,the blower stops for about a second and then the blower will stay on without the heat. the blower will continue running until you cut the power. if you leave the power off for about an hour or so and turn the power back the furnace will start and run normally , until it has another one of those fits. The furnace does have a blinking light and a chart for the codes:
incorrect twinning=reverse primary wires
incorrect polarity= reverse secondary leads
My repair man has replaced two control panels,new thermostat,igniter,and a blower sensor. He can't seem to find out what the problem is and is recommending to just buy a new furnace. any ideas??
Has your service man checked to make sure that the black wire it the hot line and white is neutral and you do have a good earth ground.
Do you have a down flow furnace? It sounds like you might have a weak
limit switch, so when the blower turns off the furnace limit switch opens and
that in turn, turns the blower back on. Does the return air on the top of your furnace turn and go back down through the floor? Does your blower came on from a electronic board or from a heat sensing fan switch? If it is a heat sensing switch that is adjustable you need to turn the fan off to a lower setting. Later Paul