HVACopediaKinghome · Heat pump
E4 Compressor discharge temperature too high
What the control is telling you
The compressor discharge temperature exceeded its limit. The Ultranixx units trip at 115 C. The outdoor unit stops to protect the compressor.
Applies to: Kinghome KM09HT1DI, KM12HT1DI, KM18HT1DI, KM24HT1DI wall mini-splits; Kinghome KM09HF1DI to KM24HF1DI wall mini-splits (Gree GFH..DA/DB); Kinghome Ultranixx Eco KD24UHO to KD60UHO outdoor units with KD..UHI air handlers; Kinghome Ultranixx cold-climate KU36UHO and KU60UHO outdoor units with KU..UH2I and KD..UHI air handlers
Likely causes
- Low refrigerant charge
- Blocked system or closed service valve
- Faulty expansion valve (Ultranixx)
- Poor airflow, fan fault or ambient above the operating range
- Overload
Test and repair steps
- Verify the charge and look for a leak.
- Open service valves and check for a restriction.
- Confirm both fans run and the coils are clean.
- Check the electronic expansion valve operation.
- Check the discharge sensor reading against its resistance chart.
Models that show this code
27 models in Kinghome KM HT1DI, Kinghome KM HF1DI, Kinghome Ultranixx Eco, Kinghome Ultranixx
Other codes on the same units
- C8 ODU drive jumper cap error
- E1 High pressure protection / high-pressure sensor fault
- E2 Indoor coil anti-freeze protection
- E3 Low pressure protection / low-pressure sensor fault
- E5 Overcurrent protection
- E6 Indoor/outdoor communication fault
- E8 High temperature resistance (overload) protection
- E9 Water overflow protection
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Source: Kinghome KM09-12-18-24HT1DI service manual, sec. 9.1 error code list; Kinghome KM09-24HF1DI service manual, sec. 11.1 error code list; Kinghome Ultranixx Eco KD24-60UHO service manual, sec. 3.3-3.4; Kinghome Ultranixx cold-climate KU36/60UHO service manual GC202306, sec. 3.3-3.4. 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.