Mitsubishi Air Conditioner Error Code E.OV3

E.OV3 indicates a regenerative overvoltage trip that occurred during deceleration or a stop command. The internal main circuit DC voltage exceeded the specified safe value as the motor slowed down and fed voltage back into the DC bus. The system shut down automatically to protect the inverter components from damage.

A reset may temporarily clear the fault and allow the unit to restart, but the error will return if the underlying cause is not addressed. Simply resetting without correcting the deceleration time setting or identifying a component issue will result in repeated trips. Address the root cause before relying on a reset as a solution.

If the fix is a parameter adjustment to the deceleration time, there may be no parts cost, only a service call fee which typically ranges from $75 to $150. If DC bus capacitors need replacement, parts and labor costs generally range from $150 to $400 depending on the unit and capacitor configuration. A failed braking resistor or inverter board replacement can range from $300 to $800 or more depending on parts availability.

The first step is to increase the deceleration time setting in the inverter parameters so the motor slows down more gradually, reducing the regenerative voltage spike. If the error persists after adjusting deceleration time, check the incoming supply voltage for overvoltage conditions, inspect DC bus capacitors for degradation, and examine the braking circuit components if equipped.

The E.OV3 trip is a protective shutdown, meaning the unit has already stopped operating to prevent damage. Repeatedly forcing restarts without resolving the cause can stress the inverter's DC bus capacitors and switching transistors over time, potentially leading to more serious component failures. It is best to diagnose and correct the fault before returning the unit to normal operation.