Robert Frost once famously fretted over which two diverging roads in the woods to take. He presented the case of a traveler that has come to a crucial decision that must be made. The same theme often rings true in HVAC diagnosis. The technician finds themselves at a diagnostic crossroads, if you will, and a choice must be made:
- The variable-speed blower motor will not run. Is it the board or is it the motor/module?
- My inverter system is throwing an error code. The service manual says it could be the compressor or the board.
- My HVAC system will not communicate. Is it the indoor control board, the outdoor control board, or the wiring?
Today I am going to review troubleshooting an inverter compressor and the control that drives it. Often in analyzing service manuals you find flow charts that look like this: