Lennox Air Conditioner Error Code E432

E432 means the inverter has detected that the DC link capacitor voltage has exceeded 480VDC, which is the high-voltage protection threshold (internally identified as inverter code 28). The inverter shuts down automatically to protect the compressor and internal electronics from damage. This can be caused by utility power surges, degraded capacitors, or a fault in the inverter's power conversion circuitry.

No, you should not attempt to operate the unit while this fault is active. The inverter has already shut down the system as a protective measure, and continuing to force restarts without identifying the root cause can cause progressive damage to the inverter board or compressor. Leave the unit off and have it inspected before returning it to regular service.

Repair costs vary significantly depending on the root cause. If the fault was a one-time power surge and no components were damaged, a service call to diagnose and clear the code may be the only expense, typically in the range of $100 to $200. If the DC link capacitors, rectifier bridge, or inverter board require replacement, parts and labor costs can range from $300 to over $1,000 depending on the specific components involved and local labor rates.

The first recommended step is to disconnect power to the outdoor unit and restart it, which may clear the fault if it was caused by a one-time transient voltage event. If the error returns after the reset, the diagnosis involves working with high-voltage DC circuits that retain dangerous charge even after power is removed. Further troubleshooting should be performed by a qualified HVAC technician with proper training and safety equipment.

Disconnecting power to the outdoor unit and restarting it is the recommended first diagnostic step and may clear the fault if a transient voltage spike was the cause. However, if the underlying condition such as degraded capacitors or a power supply issue is still present, the error will return. A reset that does not hold indicates a component-level problem requiring further diagnosis.