Gree · Heat pump
C0 Communication fault IDU/ODU/wired controller
What the control is telling you
Indoor units, outdoor unit or the wired controller are not communicating.
Applies to: Gree GMV6 Ultra Heat Mini VRF 36-60k (GMV-V..WL/C-T(U))
Likely causes
- D1/D2 wiring open, loose or mixed with H1/H2 or G1/G2
- No power at an indoor unit
Test and repair steps
- Inspect the D1/D2 bus; it must be run separately from the H1/H2 and G1/G2 terminals.
- Confirm 208/230 VAC at L1/L2 on every indoor and the outdoor unit.
Models that show this code
3 models in Gree GMV6 Mini VRF
Other codes on the same units
- b1 Outdoor ambient sensor open or shorted (15K)
- 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)
- C1 Main board to DC-DC controller communication fault
- C2 Main board to compressor drive communication fault
- C3 Main board to fan drive communication fault
- C4 Missing indoor units
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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.
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