Mitsubishi MUZ-GL09NA 9,000 BTU Single-Zone Outdoor Unit F8 Error Fix: Compressor Overcurrent Protection (CT Sensor)

Error code F8 on the Mitsubishi MUZ-GL09NA 9,000 BTU Single-Zone Outdoor Unit means: Compressor Overcurrent Protection (CT Sensor). The current transformer (CT) sensor on the outdoor PCB has detected excessive current draw from the compressor motor. The indoor LED blinks 10 times. Causes: compressor bearing wear (common in aged units), locked rotor condition, incorrect supply voltage, short in compressor motor winding, liquid slugging (liquid refrigerant flooding back to compressor). Check supply voltage at the outdoor unit terminals. Measure compressor winding resistance phase-to-phase. Check for liquid refrigerant in the suction line.

The most successful fix is "Test Compressor Windings and Replace Compressor if Faulty" (hard difficulty, ~120 minutes). Estimated DIY cost: $0-$15. HomeMD has 2 community-ranked fixes for this error.

This error is rated critical severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Yes — the top-ranked community fix ("Test Compressor Windings and Replace Compressor if Faulty") is rated hard difficulty and takes about 120 minutes. Tools needed: T20 Torx screwdriver, Digital multimeter, Refrigerant recovery equipment (for pro).

DIY cost: $0-$15. Professional repair typically costs $900-$1200. Many homeowners save money by trying the top-ranked community fix first.

The Mitsubishi MUZ-GL09NA 9,000 BTU Single-Zone Outdoor Unit has 8 other known error codes, including: F1 (Reverse Phase / Phase Loss Detection), F3 (Compressor Discharge Temperature Protection), F4 (Outdoor Heat Exchanger Thermistor Error), F5 (Compressor Overheating / High Pressure Switch Activation), F6 (Outdoor Subcooling Sensor / Pipe Thermistor Error), and 3 more.

Error code F8 also appears on 5 other Mitsubishi models: MXZ-3C30NAHZ 30,000 BTU 3-Zone Hyper-Heat Multi-Zone Outdoor Unit, MXZ-4C36NAHZ 36,000 BTU 4-Zone Hyper-Heat Multi-Zone Outdoor Unit, PUZ-A18NKA 18,000 BTU P-Series Ducted Heat Pump Outdoor Unit, PUZ-HA36NKA5 36,000 BTU Zuba Central Cold-Climate Heat Pump Outdoor Unit, SUZ-KA09NA 9,000 BTU Concealed Duct System Outdoor Unit. The fix may vary by model, so check each model's specific page for tailored repair steps.