Gree Mini Split U1 Error Code

Updated 2026-08-29 · review status: manual-verified · reviewed by MiniSplitDecoder Editorial Team Last verified: 2026-08-29

Check your model first

The source record does not specify an exact model family.

Match the model on your equipment label to the linked manufacturer documentation. The same code can mean different things across model families.

Quick answer

U1 means the outdoor unit's compressor phase-current detection circuit is malfunctioning, so the drive cannot trust current readings and protects the unit. One safe reset is the only homeowner step; the rest is technician work.

Severity: high · DIY difficulty: easy

Safety

Stop at the single power-cycle check. Current-sense circuits carry live inverter voltages - do not open the electrical box or test components. Technician-only.

What U1 means

U1 means the outdoor unit detected a compressor phase-current detection circuit malfunction. The inverter drive cannot trust the current feedback, so it protects the unit. Power events are the only homeowner-checkable cause; the detection circuit is technician work.

Causes, ranked

  1. 1. Brief power event, brownout, or unstable supply voltage common DIY

    Check: Power cycle once at the breaker and run a full cycle.

    Fix: If one reset clears it and it stays clear, monitor; if it returns, stop resetting.

  2. 2. Loose power or compressor connection feeding the sense circuit occasional pro only

    Check: Terminal inspection is inside the outdoor electrical box.

    Fix: Technician: inspect and retermine power and compressor wiring.

  3. 3. Phase-current sensor or sense-circuit fault occasional pro only

    Check: Requires inverter-drive measurements.

    Fix: Technician: diagnose the current-sense circuit and drive board.

  4. 4. Compressor winding or outdoor board fault after sense circuit tests good rare pro only

    Check: Compressor and board testing only.

    Fix: Technician: test compressor windings and outdoor PCB.

Related codes

Cross-references for the same fault family, by brand:

Gree U2 · Gree U5 · Gree U3 · Gree H7

Commonly searched as: "gree u1" · "gree error code u1" · "gree air conditioner u1"

Sources

Related Mini Split guides

Mini-Split Communication Error: DIY Checks · Mini-Split Flashing Light Decoder: Blink Patterns · How to Reset a Mini-Split After a Power Outage