I have a Goodman furnace model GMP075-3. Yesterday night the furnace stopped producing heat--the blower ran continuously. The diagnostic code was "4 blinks" meaning that the limit circuit was open. I checked all of the rollout limit controls (we had very high winds the night before the furnace stopped heating). After I checked the rollout limits, I restarted the furnace and the diagnostic code changed to "3 blinks." And after about 5 minutes the furnace blower stops.
3 blinks means the pressure/limit switch is malfunctioning. I checked the small rubber hose between the pressure switch and inducer and it seems clear. When I suck on the hose I hear a click in the pressure switch--I assume this is the switch completing the circuit. I checked for obstructions at the inducer and it too seems clear although it doesn't seem to be producing much (if any) suction--meaning that I don't think it's creating enough suction to trigger the pressure switch. I have no way of measuring the vacuum. I place my finger over the end of the inducer's valve and it doensn't "suck" down on my finger (like a vacuum would).
Could it be my pressure switch? Or is it likely the inducer not producing enough vacuum? If I bypass the pressure switch the furnace heats--but it's not safe to keep this bypassed.
Any help would be greatly appreciated.
Thanks,
"Freezing in Ohio"
3 blinks means the pressure/limit switch is malfunctioning. I checked the small rubber hose between the pressure switch and inducer and it seems clear. When I suck on the hose I hear a click in the pressure switch--I assume this is the switch completing the circuit. I checked for obstructions at the inducer and it too seems clear although it doesn't seem to be producing much (if any) suction--meaning that I don't think it's creating enough suction to trigger the pressure switch. I have no way of measuring the vacuum. I place my finger over the end of the inducer's valve and it doensn't "suck" down on my finger (like a vacuum would).
Could it be my pressure switch? Or is it likely the inducer not producing enough vacuum? If I bypass the pressure switch the furnace heats--but it's not safe to keep this bypassed.
Any help would be greatly appreciated.
Thanks,
"Freezing in Ohio"