Carrier 58PAV090 - Blower does not turn off

[M1ster_jayjay]

Just noticed it this morning that my furnace blower was not shutting down even if the outdoor AC unit is not on. I even tried to turn off the thermostat unit but the blower still runs. I looked into the furnace and all the connections are there. The main switch on the side of the furnace shuts down the entire system. I also noticed that the LED light is flashing continuously. No connections were ever changed so I dont know why it is a symptom of reversed polarity. The furnace is about 9 years old. First time this has happened. I replaced the thermostat batteries just to make sure. Sometimes when I turn on the system from the main switch i hear a relay clicking a couple of times like trying to start the blower and after a few seconds it successfully runs the blower. Another thing is that when i shut it down for awhile it takes about 5 minutes before the blower turns on.

[nomadpeo]

just curious, you mentioned 'main switch' on the side of the furnace. later you said sometimes when you turn it on by the 'main switch'..... in the second instance - are you referring to the same switch, or are you referring to your thermostat as the main switch. i was just wondering if you are turning it off and on at the furnace.

clicking of relays on the circuit board or even in a digital thermostat may be normal clicking of relays closing. the delay before the fan comes on also may be normal time delay designed into the thermostat.......this is to allow for a pre-chilling of the evaporator. there is usually a delay before the fan turns off as well.

if the fan does not shut off at all and you are indeed seeing a polarity error message, there could be a condition in the controls that needs looking into by a trained technician.

[heatseeker]

You might have a stuck relay on your circuit board or your t-stat is malfunctioning. if your prob is with the board might as well calla pro cause they will fix it right. You might also have a safety switch open.

[M1ster_jayjay]

The main switch would be the power switch on the side of the furnace (similar to a light switch). I had been observing it for a couple of days and it seems that the thermostat work because the "outdoor" unit turns off and on. It is just the blower that does not shut down. Not too many parts in the furnace, just a circuit board and a transformer. My intelligent guess would be the circuit board but wanted to make sure. Will be getting a professional to look into it this week.

[heatseeker]

let us know what happens please.