Actuator Control; Service Functions - Mitsubishi Electric Mr. Slim MXZ-2B20NA Service Manual

ACTUATOR CONTROL

9
MXZ-2B20NA MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA
Relation between main sensor and actuator
Sensor
Discharge temperature thermistor
Indoor coil thermistor
Defrost thermistor
Fin temperature thermistor
Ambient temperature thermistor
Outdoor heat exchanger temperature
Capacity code

SERVICE FUNCTIONS

10
10-1. PRE-HEAT CONTROL
If moisture gets into the refrigerant cycle, or when refrigerant is liquefied and collected in the compressor, it may interfere
the start-up of the compressor.
To improve start-up condition, the compressor is energized even while it is not operating.
This is to generate heat at the winding.
The compressor uses about 50 W when pre-heat control is turned ON.
Pre-heat control is ON at initial setting.
[How to deactivate pre-heat control]
Turn OFF the power supply for the air conditioner before making the setting.
Set the "4" of SW1 on the outdoor electronic control P.C. board to ON to deactivate pre-heat control function (MXZ-
2B20NA).
Set the "4" of SW2 on the outdoor electronic control P.C. board to ON to deactivate pre-heat control function (MXZ-
3B24NA, MXZ-3B30NA, MXZ-4B36NA).
SW1
ON
1 2 3 4
SW1
ON
1 2 3 4
Turn ON the power supply for the air conditioner.
NOTE: Pre-heat control will be turned OFF when the breaker is turned OFF.
Purpose
Compressor
Protection
Defrosting Protection
Defrosting
Protection
Control
Protection
Control
MXZ-2B20NA
39
Actuator
Outdoor
LEV
fan motor
SW2
ON
1 2 3 4 5 6
SW2
ON
1 2 3 4 5 6
4-way
valve
SW2
SW1
SW871
MXZ-3B24NA
MXZ-3B30NA
MXZ-4B36NA