M-Thermal System Protection In Common; Trouble And Causes Of Heat Pump - Midea LRSJF-V120 Technical Manual

MCAC-RTSM-2012-07

2. M-thermal system protection in Common

2.1 Compressor protection.
When the power is on, or the machine stops then restarts right away, outdoor unit will run in 3 minutes to protect
the compressor from too frequent starts and stops.
2.2 When the protection device functions, running stops. Refer to the following:
① Forced to start but not possess the start article, and display light lights.
② When the operation mode is cooling, inlet and outlet of outdoor unit are blocked, outside strong air blows
into outdoor unit's outlet.
③ When heating running, dust adheres to air filter to block inlet or outlet of outdoor unit.
Note: when protecting, please cut the manual power switch. After checking the reason and solving it, restart.
2.3 Power fails.
① If the power supply fails while machine is running normally, system will record this.
② When the machine is powered on again, the running light of wire controller would flash to inform user
about this.
③ Press the on/off key of wire controller to confirm this before restart the system.
Note: When running, if system takes place mistaken operation or lighter, please pull down the power supply
switch to cut it off. Before restarting machines, please press the on/off key again as above.

3. Trouble and causes of heat pump

If one of the following malfunctions occur, stop operation, shut off the power, and contact with your dealer.

The lamp is flashing rapidly after turn off the power and turn on again.

Remote controller receives malfunction or the button does not work well.

A safety device such as a fuse, a breaker frequently actuates.

Obstacles and water enter the unit.

Water leaks from indoor unit.

Other malfunctions.
If the system does not properly operate except the cases above mentioned or the malfunction above mentioned
is evident, investigate the system according to the following procedures.
Symptom
Unit does not start
Water flowing normally but
completely can't cooling
Units start or stop
frequently
Low cooling effect
Causes

Power failure.

Power switch is off.

Fuse of power switch may have burned.

Batteries of remote controller exhausted
or other problem of controller.

Temperature is not set correctly.

Be in 3 minutes protection of
compressor.

Refrigerant is too little or too much.

Air or no concreting gas in the system

Compressor is malfunction.

Voltage is too high or too low.

System circuit is blocked.
 Outdoor unit and indoor unit heat 
M-thermal Technical Manual (part 4)
Solution

Wait for the comeback of power.

Switch on the power.

Replace Location:

Replace the batteries or check the
controller.

Set the temperature properly.

Wait.

Check leakage, recharge refrigerant.

Vacuum and recharge refrigerant.

Maintenance or change compressor.

Install manostat.

Find reasons and solution.
Clean the heat exchanger.