What causes Over/Under Voltage Code 7 on Heat Controller Heat Pump and how to fix it?
- TTrevor GutierrezAug 18, 2025
The Code 7 on your Heat Controller Heat Pump indicates an over or under voltage issue. If it is undervoltage, check the power supply and the 24VAC voltage, both before and during operation. Also, examine the power supply wire size and consider if a hard start kit is needed for the compressor. Verify the 24VAC and the unit transformer tap are set for the correct power supply voltage. If it is overvoltage, check the power supply voltage and the 24VAC before and during operation. Also, verify the 24VAC and unit transformer tap for the correct power supply voltage.