Midea M2OA-18HRN1, Technical & Service Manual

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8.5   Protection 
8.5.1  The compressor functions protection with a delay of three minutes. 
8.5.2  High temp. protection of condenser. 
8.5.3  Sensor protection at open circuit and breaking disconnection 
8.5.4  Temperature Fuse break protection 
8.5.5  Fan Speed is out of control. When Indoor Fan Speed is too high(higher than High 

Fan+300RPM)or too low(lower than 400RPM), the entire unit stops and LED displays 
failure information and can’t returns to normal operation automatically. 

8.6   Fan-only mode 

Fan speed is high/mid/low/ Auto

8.7   Cooling mode 

The 4-way valve is closed under cooling mode.   
The action of the compressor and the outdoor fan: 

 Condition 

Compressor 

Outdoor 

fan 

TA> Ts+1 

On 

On 

Temp. up 

TA<Ts+1 Off 

Off 

TA> Ts 

On 

On 

Temp. down 

TA<Ts Off 

Off 

TA: Indoor ambient temperature 
TS: Setting temperature through the remote controller 

Auto fan under cooling mode: 

 Condition 

T=Indoor Temp.-Setting Temp. 

Indoor fan speed 

T<3

℃

 Low 

3

℃

<T<5

℃

 Med. 

Temp. up 

T>5

℃

 High 

T> 3

℃

 High 

1

℃

<T<3

℃

 Med. 

Temp. down 

T<1

℃

 Low 

Anti-freezing control to indoor evaporator under cooling mode 

Condition 

Temp. Time 

Compressor Outdoor 

fan 

T> TE6 

On 

On 

Temp. up 

T< TE6 

>5 Minutes 

Off 

Off 

T> TE5 

On 

On 

Temp. down 

T< TE5 

>5 Minutes 

Off 

Off 

      Condenser high-temperature protection under heating mode 

 T3 >65

℃

, turn off compressor. 

TE5: Evaporator low temperature protection entering temperature 

TE6: Evaporator low temperature protection restoring temperature 

8.8    Dehumidifying mode 
8.8.1  The 4-way valve is off in dehumidifying mode 
8.8.2  Compressor and Indoor Fan actions in dehumidifying mode 

Compressor run 5 minutes , and indoor fan run 5 minutes in low speed, then turn off the