UA
Mitsubishi · MXZ-3C30NAHZ 30,000 BTU 3-Zone Hyper-Heat Multi-Zone Outdoor Unit
The indoor and outdoor units have an incorrect combination or address configuration. Verify model compatibility using the Mitsubishi Electric compatibility chart. Check all DIP switch and rotary switch settings against the installation manual.
Error UA on the Mitsubishi MXZ-3C30NAHZ 30,000 BTU 3-Zone Hyper-Heat Multi-Zone Outdoor Unit means: Address / Combination Setting Error. The top-ranked community fix is “Reprogram or Replace Faulty Address/Combination Control Board” (medium difficulty, ~45 min, DIY cost: $0-$20). 2 community-ranked fixes available below.
Published February 2026 · 2 fixes · mini split
Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.
While many mini split repairs can be done safely at home, consider hiring a qualified technician if:
Average professional repair cost for this issue: $150-$300.
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
heat_pump · 2 fixes
heat_pump · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
mini_split · 2 fixes
heat_pump · 2 fixes
mini_split · 2 fixes
Reverse Phase / Phase Loss Detection
Compressor Discharge Temperature Protection
Outdoor Heat Exchanger Thermistor Error
Compressor Overheating / High Pressure Switch Activation
Outdoor Subcooling Sensor / Pipe Thermistor Error
High Head Pressure Protection
Compressor Overcurrent Protection (CT Sensor)
Heat Sink / Power Module Overheat Protection
The Mitsubishi MXZ-3C30NAHZ 30,000 BTU 3-Zone Hyper-Heat Multi-Zone Outdoor Unit has 8 other known error codes:
Error code UA also appears on 14 other Mitsubishi models:
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