Mitsubishi Electric Mini-Split Code UF
Soft lockout
Compressor overcurrent interruption with the compressor locked. Overcurrent on the DC bus or compressor was detected within 30 seconds of the compressor starting, which points at a seized or stalled compressor.
Manual wording: “Compressor overcurrent interruption (When compressor locked) - Abnormal if overcurrent of DC bus or compressor is detected within 30 seconds after compressor starts operating.”
Documented for: A-Control outdoor units (PUZ, MUZ, MXZ)
Likely causes, most common first
- Stop valve is closed
- Decrease of power supply voltage
- Looseness, disconnection or reversed connection of the compressor wiring
- Defective compressor
- Defective outdoor power circuit board
- DIP switch setting difference on the outdoor controller circuit board
What you can safely check yourself
- Check that the breaker feeding the outdoor unit is on and has not tripped
- Turn the system off at the breaker, wait one minute, and turn it back on once
When to call a technician
A locked compressor, closed stop valve or compressor wiring fault all require a technician. Do not keep resetting the breaker to force it to start.
A Mitsubishi Electric mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Service Manual No. OCH750 Revised Edition-E - PUZ-HA Outdoor Units (May 2024) (Mitsubishi Electric, PUZ-HA24NHA1, PUZ-HA30NKA, PUZ-HA36NKA, PUZ-HA42NKA1 heat-pump outdoor units) · checked 2026-08-25