DIY HVAC Tools

Cooper & Hunter mini split error code U5

Whole-unit current detection error.

  • TypeFault
  • SystemControl board
  • Can I fix it?Technician job

What U5 means on a Cooper & Hunter

The outdoor board's current-sensing circuit is returning an impossible value.

On this platform, U5 is a fault: something has failed or is disconnected and needs diagnosis.

Common causes

  • A failed current sensor or board.
  • A loose connection on the board.

How to fix it yourself

Do the reset and the visual checks, but the underlying repair needs a technician with a meter and the service manual.

  1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

Board-level fault for a technician.

Which Cooper & Hunter units show U5

This page applies to Cooper & Hunter Sophia, Astoria, Olivia, Dakota, Hyper Heat, Alice and MIA units. Cooper & Hunter's own documentation lists U5 as "Whole-unit current detection error", the same definition used across the Gree platform it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.

Where Cooper & Hunter shows this code

The code shows on the indoor unit's display in place of the temperature. If the display is off, press the Light button on the remote. Some models also count out the code as indicator blinks. E codes are system protections and faults, F codes are mostly sensor faults, H codes are outdoor and compressor protections, U codes are motor and valve faults, and P codes are power-supply faults.

Other Cooper & Hunter codes

Same part of the system as U5:

EEEEPROM (memory) error on a control boardC5Jumper cap malfunction (missing or wrong jumper)PcCurrent sensor errorPdSensor connection protection
E1High pressure protectionE2Indoor anti-freeze protectionE3Low pressure protection (refrigerant shortage or blockage)E4Compressor discharge temperature too highE5Over-current protectionE6Communication error between indoor and outdoor unitsE7Mode conflict (multi-zone)E8High temperature protection (overheating)

All Cooper & Hunter error codes

U5 on other brands

The same characters do not always mean the same thing. Check the brand on your unit.

Questions people ask

Can I reset a Cooper & Hunter U5 code myself?

Yes. Turn the system off at the breaker for five minutes, then restart it. If U5 comes back, the fault is real and needs the checks above.

Is it safe to keep running a Cooper & Hunter showing U5?

The unit will usually refuse to run, or run with reduced output, until the fault is cleared. Repeated resets do not fix anything and can mask a problem that is getting worse.

What will a technician check for U5?

Board-level fault for a technician. Ask for the measurements, not just a parts quote.

Sources

  • Cooper & Hunter error code list and owner's manuals
  • Gree residential split service manuals

Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.