Compressor start and system protections

What happens, in order

1. First compressor start waits 1 minute; later restarts wait 3 minutes
2. Indoor/outdoor communication no feedback from the outdoor unit for 2 minutes stops the unit and shows a failure code
3. Outdoor anti-freeze capacity demand drops to zero when T2 is below 4 C for 250 s or below 0 C; normal running resumes when T2 is above 8 C and at least 3 minutes have passed
4. Low ambient with the compressor off, T4 below -35 C for 10 s stops the unit and shows LP; with the compressor on, T4 below -40 C for 10 s does the same; it exits when T4 is at or above -32 C for 10 s
5. Low voltage unit restarts 3 minutes after the protection clears, if voltage returns within that time
6. Four-way valve is open in heating and closes 2 minutes after the compressor stops when leaving heating; on any fault (except discharge temperature, high or low pressure) it closes immediately

Timings and thresholds

Codes you may see during this

LP

Models

More Midea heat pump sequences

• Multi-zone defrost entry and exit · Defrost