Have a Carrier Day and Night Heater model # 395AAW03 60SSAEA 1983
When we bought the house my husband took out and cleaned the blower and put in a new filter. It worked fine for about a month and then about a week ago we started smelling a “hot” smell – kinda smelled like an iron left on. A few days later I noticed that the heater would turn on- but seemed to not stay on very long as it was not keeping the house warm even when the thermostat was turned up high. We bypassed the thermostat and it would turn on run for a few minutes then turn off, then start again awhile later and run for a few more minutes. How long it ran varied from about 30 seconds to 20 min or so. Yesterday when I checked it would not turn on but the pilot was staying lit (it should be lighting each time from my understanding not staying lit)- it stayed lit even when you took the front panels off and the kill switch should have turned it off. So I turned off the gas to shut it off and am now hoping for help on what might be the problem.
I might be right off base but wouldn't an 83 be likely to just be an natural draft furnace with a conventional pilot and thermocouple. The pilot staying on would be normal and what we are probably talking about is a faulty blower motor.
I would be interested in what happens if the summer fan switch is pushed on. I also wonder if the fan motor does run for short periods of time if it is almost too hot to touch. Note# Only touch this motor after the power is turned off to the furnace.
Does the squrrel cage still move easily? Is it a direct drive or does the motor include a belt & pulleys/
Pictures of the furnace & inside the motor compartment would help.