Vari. Speed AH Motor issue

[saloh01]

I was at a call yesterday with a Carrier/Bryant Variable Speed Air Handler, Model#: FV4BNF003, the motor is running at a very low speed, and will not pick up speed, switched the fan to on at the thermostat and moved the pin on the easy select board to high on the continuous fan section of the board but the motor is still moving at a slow rate of speed with minimal change with door on and off. Ductwork is in good condition with no collapsed ductwork. Any ideas on what I should look for, I would think something is wrong with the module on the motor.

Thanks for any help.

[jrpsimivalley]

u need an ecm motor tester it plugs into the module between board and module, high voltage stays put, then kick it on, it should run the motor thru all speeds, only way to tell if it's the board or mod

[Stephen260B]

Is this a new system that has never worked correctly or an older one that has stopped working?

[saloh01]

The system is 3 years old, everything has been working fine up until 2 days ago the homeowner said.

[DavidsHeatAC]

Capacitor maybe? which on ECM they are internal and you cant replace them, Or thats what we have been led to believe.

[JediMickey]

I was at a call yesterday with a Carrier/Bryant Variable Speed Air Handler, Model#: FV4BNF003, the motor is running at a very low speed, and will not pick up speed, switched the fan to on at the thermostat and moved the pin on the easy select board to high on the continuous fan section of the board but the motor is still moving at a slow rate of speed with minimal change with door on and off. Ductwork is in good condition with no collapsed ductwork. Any ideas on what I should look for, I would think something is wrong with the module on the motor.

Thanks for any help.

test the eletric heat it should kick it in high speed. use a ecm motor tester if it won't go in any other speed and is stuck in low check wiring harrnes then it is a bad board.

[allan38]

Some carrier ecm motors will run at half speed when the G terminal is not energized and Y is energized. Dropping the G input signals the board to go into dehumidify mode. Make sure you haven't lost the g input. I don't remember if that behavior is restricted to just furnaces or if it is included in air handlers also.