Automatic defrost

What happens, in order

1. Defrost is considered after 45 minutes of continuous heating or 90 minutes of accumulated heating
2. Entry also needs the outdoor coil to be cold enough for the outdoor air temperature: above 5C air with coil at -2C or lower; -2 to 5C air with coil at -6C or lower; -5 to -2C air with coil at -8C or lower; colder air uses a compensated comparison
3. Defrost starts 3 minutes after the conditions are met
4. Indoor fan and compressor stop
5. 30 s later the outdoor fan stops
6. 30 s later the reversing valve switches (de-energizes)
7. 30 s later the compressor starts and ramps to defrost frequency (85 Hz)
8. After 7.5 minutes of defrost, or if outdoor air is 10C (50F) or above, the compressor drops to 46 Hz
9. 30 s later the compressor stops; 30 s after that the reversing valve switches back to heating
10. 60 s later the compressor and outdoor fan restart and the indoor fan resumes under the anti-cold-air rules
11. The remote shows H1 while defrosting (normal, not a fault); the indoor unit panel does not show it

Timings and thresholds

Codes you may see during this

H1

Models

More Gree mini-split sequences

• Compressor restart delay and minimum run time · Startup
• Anti-cold-air indoor fan delay · Heating
• Heating mode · Heating
• Heating mode (outdoor logic) and special modes · Heating
• Heating mode and anti-cold-air · Heating
• Heating, defrost, oil return and mode conflict · Heating
• Cooling and dry mode (multi-zone) · Cooling
• Cooling and dry mode with protections · Cooling