View Full Version : What does a limit switch do on an goodman ac unit
neilro2
Jun 23, 2012, 09:16 AM
I have a goodman ac unit split system,the blower motor starts running and runs for about 5 or 6 seconds then shuts off.I have replaced the capacitor and the circuit board.I was told that I may need a limit switch can someone tell me if they think that will fix the problem or that I need a blower motor--HELP
Frank Mangrum
Jun 23, 2012, 10:55 AM
I am not aware of a limit switch that is in motor control circuit during cooling mode of operation other than thermal and overload controls built into motor itself---they are not replaceable other than replacement of motor. If heat mode limit opens (mostly does this during heat cycle) this would start blower motor and it would run continuously while limit switch is open. Does motor shaft turn freely? Any unusual noises when motor is running? Does motor feel warm or hot when it shuts off? Could be motor failure---need more information to be sure.
thermalmedics
Jun 23, 2012, 02:35 PM
What happens when you turn the blower motor on by itself.
t-stat fan switch from auto to on?
Same deal?
Check all wires have solid connections
Can try pulling cover off t-stat and wire nut red and green - same thing?
If it is not to gnarly to run in heat mode - even for a minute or so - try that and see if you get normal operation.
If you get the same result - you can check blower motor voltage with a meter on a demand at the blower motor (tstat calling for fan on). If you are getting the necessary 120 or 240 volts required and the voltage is sustained for half a minute or so than yes go for a new blower motor.
neilro2
Jun 23, 2012, 05:56 PM
Thanks for all your help,I am going to replace the blower motor.I will let you know if that was the fix.