Hello. I’m a pro HVAC guy wanting to learn how to do more than just replace these expensive circuit boards. The higher efficiency heat pumps have 3 phase A/C or DC motors, pressure transducers, thermistor temperature sensors, secret communication between units and very little training is being provided. Mini split hp’s are finally gaining traction in the USA, but few of us can do more than install or perform minor troubleshooting/repairs at this time.

I have been totally off grid for two years generating 1000-2000kWh/per month. So, I would like to learn how to repair high/low...