Haier 1UH071N1ERG [213/238] Smart power

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Smart Power

6.2.4 Oil return control

Control purpose: Make the system oil regularly return to the compressor when the compressor work in a low

frequency.

Condition:

When the indoor units are working, if the compressor continuous frequency is lower than the parameters C HZ (E)

and the temperature TC is lower than 50°C (E) ,and it lasts 5 hours. Unit will enter oil return mode. When changing

the mode or manual stop or protective stop, time will pause. After the compressor restart, it will continue to time.

When timing, if the compressor working frequency is higher than B HZ (E) and lasts more than 10 minutes, the time

reset.

When heating, the time will reset if the defrost mode work.

After oil return, oil return timer reset

After oil return, the condition of end of refrigerant ruled running

Oil return after 1 minutes

The longest 3 minutes

Td-TC>30°C

Ts-TM>30°C

TM<-35°C

Process control chart of oil return:

Send oil return signal Start End

60S Refrigerant ruled working

Oil return frequency B Hz（E） Auto

40HZ （ E ）

Inverter compressor Auto frequency

300 pulses（E）

PMV Auto opening Auto

120pulses（E）

OD fan Auto working Auto working Auto working

ID fan

Auto working Auto working Auto working

4-way valve OFF OFF OFF

SV valve (auto running according to some condition)

30s