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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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American standard 90 furnace blower short cycles

Customer Question

American standard 90 furnace blower short cycles
Submitted: 2 years ago.
Category: HVAC
Customer: replied 2 years ago.
unit on cooling Red light on then blower starts just get to speed and then shut off for 20 seconds and starts again
Expert:  Stingray replied 2 years ago.
Hello, My name is ***** ***** I will do my best to help you out.First I need the Model number to better assist you.Freedom 90 is just it's marketing name. The Model number would be found inside the burner compartment and there is a label s located on the right of left side of the indoor unit .
Customer: replied 2 years ago.
Customer: replied 2 years ago.
Expert:  Stingray replied 2 years ago.
Alright, what we have to do is determine whether it is the board thermostat or fan motor.You will need a volt meter for this capable of reading both 120VAC and 24VAC.First we need to test on the board itself where the thermostat control wires go, should have 24VAC +/- 10% between R-C. There is a power switch that you will have to push in to get power going to the board.If that checks out now we need to disconnect all control wires for the thermostat, take note of where each one we put a jumper wire from R-G and push the safety switch in and the blower should come on and stay running. If it has the same symptoms as before then we need to check power going to the motor. If you have a clampon amp meter that would be helpful if we have to go any further.Let me know what your results are.

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