Actuator Control; Service Functions; Pre-Heat Control; How To Deactivate Pre-Heat Control - Mitsubishi Electric MXZ-2B20NA Service Manual

9

ACTUATOR CONTROL

MXZ-2B20NA MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA MXZ-5B42NA
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
10

SERVICE FUNCTIONS

MXZ-2B20NA MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA MXZ-5B42NA

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 electronic control P.C. board to ON to deactivate pre-heat control function (MXZ-2B20NA).
Set the "4" of SW2 on the electronic control P.C. board/outdoor control P.C. board to ON to deactivate pre-heat control
function (MXZ-3B24NA, MXZ-3B30NA, MXZ-4B36NA, MXZ-5B42NA).
MXZ-2B20NA
Electronic control
P.C. board
Turn ON the power supply for the air conditioner.
NOTE: Pre-heat control will be turned OFF when the breaker is turned OFF.
OBH560G
Purpose
Compressor
Protection
Defrosting Protection
Defrosting
Protection
Control
Protection
Control
MXZ-3B24NA
MXZ-3B30NA
MXZ-4B36NA
SW2
ON
SW2
SW1
SW871
1 2 3 4 5 6
SW2
ON
Electronic control
P.C. board
1 2 3 4 5 6
54
Actuator
Outdoor 4-way
LEV
fan motor valve
MXZ-5B42NA
Outdoor control P.C. board
Solenoid
valve
(MXZ-5B)