Daikin VRVIII-S Service Manual page 176

SiENBE34-703
Troubleshooting
∗2: Voltage measurement point
∗1: Refer to "Thermistor Resistance / Temperature Characteristics" table on P225.
∗2: Refer to "Pressure Sensor, Pressure / Voltage Characteristics" table on P227.
Troubleshooting
Be sure to turn off power switch before connect or disconnect connector,
Caution
or parts damage may be occurred.
YES
Cooling
NO
The
suction pipe1
temp. minus low
pressure saturation temp.
is 20 °Cor higher.
NO
Resistance
is normal when
measured with the
thermistor (R3T) for
suction pipe1 disconnected
from the outdoor unit
PC board.∗1
YES
Is the low
pressure sensor
correct?
YES
Outside unit PC board A2P
GND
Microcomputer
A/D input
*2 Measure DC voltage here.
Troubleshooting by Indication on the remote control
Low pressureis 0.25
MPaor less.
NO
The
voltage of
X18A pins (2) and
(3) on main outdoor unit
PC board (A1P) is 1.0 VDC or
less. (Low pressure sensor
output voltage) ∗2
NO
YES
NO
NO
+5V
X45A
4
3
2
1
YES
Out of gas, closing of stop
valve or refrigerant system is
clogged. Requires check of
refrigerant system.
YES
Replace main outdoor unit
PC board (A1P).
Replace low pressure sensor.
Out of gas or refrigerant
system is clogged. Requires
check of refrigerant system.
Replace the thermistor.
Replace the low pressure
sensor.
Replace the outdoor unit PC
board (A1P).
Red
Black
White
(V2809)
(V2819)
165