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Gree · Heat pump

U8 Indoor zero-crossing signal fault

Medium severity Gree SapphireGree Livo GEN4Gree Vireo GEN3Gree Multi21+

What the control is telling you

The indoor board cannot see the power zero-crossing signal it uses to drive the fan motor; the whole unit stops.

Applies to: Gree Sapphire 9-24k (SAP..HP230V1A), Livo GEN4 30-36k (4LIV..HP230V1A), Vireo GEN3 9-24k (3VIR..HP115/230V1A), Multi21+ 18-24k multi-zone (MULTI..HP230V1CO)

Likely causes

  • Power switched off and back on too quickly (capacitor still discharging)
  • Supply abnormal
  • Indoor board detection circuit fault

Test and repair steps

  1. Turn power off for 1 minute and restart.
  2. Check the supply voltage.
  3. If the code stays, replace the indoor board.

Models that show this code

14 models in Gree Sapphire, Gree Livo GEN4, Gree Vireo GEN3, Gree Multi21+

3VIR09HP115V1A3VIR09HP230V1A3VIR12HP115V1A3VIR12HP230V1A3VIR18HP230V1A3VIR24HP230V1A4LIV30HP230V1AH4LIV36HP230V1AHMULTI18HP230V1COMULTI24HP230V1COSAP09HP230V1AHSAP12HP230V1AHSAP18HP230V1AHSAP24HP230V1AH

Other codes on the same units

  • P8 Inverter module overheated
  • U1 Compressor phase current sensing fault
  • U3 DC bus voltage drop
  • U5 Whole-unit current sensing fault
  • U7 Reversing (4-way) valve fault
  • U9 Outdoor zero-crossing fault
  • EE EEPROM / memory chip fault
  • EU Compressor slowed - module running hot

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Source: Gree Sapphire 9-12k (SAP09-12HP230V1A) service.pdf - section 9.1 Error Code List / 9.2 Procedure of Troubleshooting; Gree Sapphire 18-24k (SAP18-24HP230V1A) service.pdf - section 9.1 Error Code List / 9.2 Procedure of Troubleshooting; Gree Livo GEN4 30-36k (4LIV30-36HP230V1A) service.pdf - section 9.1 Error Code List / 9.2 Procedure of Troubleshooting; Gree Vireo GEN3 9-24k (3VIR..HP115-230V1A) service GREE_VIREOGEN3_SERVICE_090921.pdf - section 9.1 Error Code List / 9.2 Procedure of Troubleshooting; Gree Multi21+ multi-zone 18-24k (MULTI18-24HP230V1CO) service.pdf - section 9.1 Malfunction status sheet / 9.2 Malfunction Checking and Elimination. Summarized in our own words; check the original manual for your model.

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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.