Carrier Infinity Heat Pump not coming on

[Mike_R]

Model 25HNB636A300

It's been cold the past 2 weeks, now that it is warmer I noticed that the heat pump portion of our furnace is not coming on. We get electric heat and there is no error on the thermostat. The outdoor fan spins freely and the compressor starts when I manually close the contactor. Tomorrow I'll check the start cap for the fan motor, but in the meantime - should the outside fan come on when I push in the contactor? I have a solid yellow and green LED on the outside unit control board. Is this normal? {It looks like it might indicate Standby, but I don't know what that means.}

Really don't know at this point if it is even being told to start, that's the trouble with these intelligent circuit boards!

Any troubleshooting information or links will be appreciated.

[HayZee518]

contactor

sure, the fan will start if that's what the contactor is connected to!
But pushing in the contactor crossbar isn't the way its supposed to work.
Look towards the control circuit that operates it.
Find the one line diagram or ladder diagram [schematic] and trace out the circuit to the fan motor contactor.
There are devices connected in series BEFORE the contactor's coil.

[Mike_R]

Fixed itself

Hate it when that happens. Cleaned the filter and had my wife turn up the thermostat - heat pump came on fine and has been working ever since. This unit has a RS485 connection between the thermostat and indoor and outdoor units - so it's hard (for me at least) to troubleshoot. In any event - solid green and yellow lights are OK, that just means there are no errors and it's waiting for a command from the controller. The service manual has no schematics for the boards, so that's no fun. Just glad that it's working now. Thanks for reading.