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Gree · Heat pump

C1 Main board to DC-DC controller communication fault

High severity Gree GMV6 Mini VRF

What the control is telling you

The outdoor main control cannot talk to one of its drive boards.

Applies to: Gree GMV6 Ultra Heat Mini VRF 36-60k (GMV-V..WL/C-T(U))

Likely causes

  • Compressor or fan motor fault pulling down the drive
  • Board fault

Test and repair steps

  1. Ohm-check the compressor and fan motors (equal windings, open to ground).
  2. If the motors are good, replace the outdoor control board.

Models that show this code

3 models in Gree GMV6 Mini VRF

GMV-V36WL/C-T(U)GMV-V48WL/C-T(U)GMV-V60WL/C-T(U)

Other codes on the same units

  • b2 Defrost (coil) sensor open or shorted (20K)
  • b4 Sub-cooler liquid outlet sensor open or shorted (20K)
  • b6 Accumulator inlet sensor open or shorted (20K)
  • C0 Communication fault IDU/ODU/wired controller
  • C2 Main board to compressor drive communication fault
  • C3 Main board to fan drive communication fault
  • C4 Missing indoor units
  • d1 Indoor main board fault

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Source: Gree GMV6 Ultra Heat Mini VRF 36-60k (GMV-V36-48-60WL-C-T(U)) service.pdf - section Chapter 3 Faults, 4.1 Error Indication. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.