Pressure Sensor; Electric Expansion Valve; Rb Unit (Heat Recovery Type Only); Others - Fujitsu AB12 Service Manual

8-5-2 PRESSURE SENSOR

1) Characteristics of pressure sensor
V
5
3
1
0
2) Check point of replacing pressure sensor
Pressure sensor
When installing the pressure sensor, connect a lead wire to the PCB (
of a lead wire to the pressure sensor (
Be careful not to install other than above procedure, otherwise the pressure sensor can be failed.

8-5-3 ELECTRIC EXPANSION VALVE

When the electric expansion valve is locked cause by failure, it emits click noise. Confirming the noise
emission is done by touching any implement like a screw driver.

8-5-4 RB UNIT (HEAT RECOVERY TYPE ONLY)

When the RB unit is failed, it can be concerned one of the valve such as discharge valve, suction valve
and bypass is locked. The discharge valve will be ON during heating operation, the suction valve will be
ON during cooling operation and the bypass valve will be ON during stopping.

8-5-5 OTHERS

1) Solving the problem is nesessary since following can be occured.
1 Gas leakage, capacity declining cause by gas shortage.
2 Dirt from the filter and the EEV.
3 Capacity declining by mis-setting of the indoor unit capacity.
Unfit of the refrigerant pipe.
4
5 Increasing the indoor unit by mis-piping.
6 Increasing the indoor unit by mis-setting the refrigerant system address.
7 Disconnection of the transmission line.
2) The air conditioner operates intermittently or an error message appears.
Wiring method of the transmission line.
1
2 Loose contact of the transmission line
3 Mis-selecting the transmission line.
Over the limit of the transmission line length.
4
5 Noise influences the transmission line.
6 In case of the specified indoor unit, the indoor unit PCB is defected.
In case of all units or the specified unit, the outdoor unit PCB is defected.
7
1.75 3.5
Pressure
Lead wire
Printed circuit board
). When disconnecting, do the opposite procedure.
– 126 –
MPa
), thereafter connect the other end