Daikin RMXS-L Series Service Manual page 219

SiUS181305E
Troubleshooting
1: Voltage measurement point
Refer to Thermistor Resistance / Temperature Characteristics table 1 on page 224.
For pressure / voltage characteristics graph, refer to Pressure Sensor on page 226.
Troubleshooting
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
YES
Cooling?
NO
Is the
suction pipe 1
YES
temp. minus low pressure
saturation temp. 20˚C
(36˚F) or more?
NO
Resistance is
normal when
NO
measured after
disconnecting the
thermistor
(R3T).
YES
Is the low
NO
pressure sensor
correct?
YES
Main PCB A1P
Microcomputer
A/D input
Low pressure is YES
0.25 MPa (84 ftAq)
or less?
NO
The voltage
between the pins 2
YES
and 3 of X18A is 1.0 VDC
or less? (Low pressure
sensor output
voltage)
∗1
NO
+5V
X18A (Blue)
GND
Measure the voltage here.
Troubleshooting for Outdoor Unit
Refrigerant shortage,
closed stop valve or
refrigerant system is
clogged. Check the
refrigerant system.
Replace the main PCB
(A1P).
Replace the low pressure
sensor.
Refrigerant shortage or
refrigerant system is
clogged. Check the
refrigerant system.
Replace the thermistor.
Replace the low pressure
sensor.
Replace the main PCB
(A1P).
(R19096)
(4) Red
(3) Black
(2) White
(1)
(R13043)
210