Carrier on the roof

Old 11-03-00, 04:47 PM
Visiting Guest
Posts: n/a

I have a Carrier heating/air conditioner. When I turn on the air everything is fine. When I turn on the heat or just the fan the blower dosen't come on. I have got a wiring diagram and have checked the wiring in the unit as ok. The relay does come on for the fan and relay contacts do work. I have tryed swaping the low and high wires ti the air relay and the fan still comes on with the air (now at the low speed) but the fan doesnt come on with the heat still. Any suggestions??
Old 11-04-00, 07:09 AM
Visiting Guest
Posts: n/a

check for voltage from heat connection on board. Sometimes you'll hear the heat relay click, but the points are bad and does not send power to motor. If no voltage present, replace board.
Old 11-04-00, 07:20 AM
Visiting Guest
Posts: n/a


If the burners fire-up but the fan fails to turn on, then it's most likely the fan switch.

The burners should fire-up and pre-warm the firebox <heat exchanger> then several minutes after the burners have been on the fan should start-up.

If the fan doesn't turn on, the burners will turn off. If this happens, then the defective part is most likely the fan switch.

Turn off all electric power FIRST! Remove the fan switch and have the local appliance parts store test it. If defective, replace it with an exact OEM replacement part which will have the settings pre-set at the factory.

Good Luck,
Natural Gas Energy Technician and Consultant.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: