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Gree · Heat pump

U3 DC bus voltage drop

Medium severity Gree SapphireGree Livo GEN4Gree Vireo GEN3

What the control is telling you

The DC bus voltage dropped suddenly.

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

Likely causes

  • Unstable or dipping supply voltage

Test and repair steps

  1. Check supply voltage and connections under load.
  2. Have the supply corrected; replace AP1 if supply is stable.

Models that show this code

12 models in Gree Sapphire, Gree Livo GEN4, Gree Vireo GEN3

3VIR09HP115V1A3VIR09HP230V1A3VIR12HP115V1A3VIR12HP230V1A3VIR18HP230V1A3VIR24HP230V1A4LIV30HP230V1AH4LIV36HP230V1AHSAP09HP230V1AHSAP12HP230V1AHSAP18HP230V1AHSAP24HP230V1AH

Other codes on the same units

  • P5 Compressor phase overcurrent
  • P7 Inverter module temperature sensor fault
  • P8 Inverter module overheated
  • U1 Compressor phase current sensing fault
  • U5 Whole-unit current sensing fault
  • U7 Reversing (4-way) valve fault
  • U8 Indoor zero-crossing signal fault
  • U9 Outdoor zero-crossing fault

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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. 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.