Midea MS11D-12HRN1 [43/56] Main protection

DM12-01.01.07en Neola On-off

Service manual 43

10.3 Main Protection

10.3.1 Time Delay at restart for compressor.

10.3.2 Sensor protection at open circuit and breaking disconnection.

10.3.3 Zero crossing detection error protection

If AC cannot detect zero crossing signal for 4 minutes or the zero crossing signal time interval is not

correct, the unit will stop and the LED will display the failure. The correct zero crossing signal time

interval should be between 6-13 ms.

8.3.4 Fan Speed is out of control

When Indoor Fan Speed is too low(lower than 300RPM) lasting 50 seconds, the unit stops and LED

displays failure information and can’t returns to normal operation automatically.

10.4 Operation Modes and Functions

10.4.1 Fan mode.

(1) Outdoor fan and compressor stop.

(2) Temperature setting function is disabled, and no setting temperature is displayed.

(3) Indoor fan can be set to high/med/low/auto.

(4) The louver operates same as in cooling mode.

(5) Auto fan:

10.4.2 Cooling Mode

10.4.2.1 Compressor running rules:

Once the compressor starts up, it will follow the below rules:

When indoor room temp.T1 is lower than Tn, the compressor and outdoor fan will shut off. When T1 is

higher than Tm, the compressor and outdoor fan will start up. (If the unit has refrigerant leakage Detect

function, the compressor will run 5.5 minutes first.)