Wet Operation Check - Daikin VRV S RXQ4/5ARV1 Service Manual

Check
6.5

Wet Operation Check

CHECK 5 Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points.
Refrigerant stagnation
Overcharge of refrigerant
[In cooling]
Indoor unit
electronic
expansion
valve opens too
much. (∗1)
Defective control
of superheating
degree
Wet operation
Degraded
evaporating
capacity
Note(s)
1: Superheating temperature control in cooling is conducted by indoor unit electronic
expansion valve.
2: Guideline of superheating degree to judge as wet operation
(1) Suction gas superheating degree: Less than 3°C;
(2) Discharge gas superheating degree: Less than 15°C,
except immediately after compressor starts up or is running under dropping control.
(Use the above values as a guide. Depending on the other conditions, the unit may be normal
despite the values within the above range.)
Reference
CHECK 6 Refer to page 345.
344
Defective crankcase heater
Frequent ON/OFF of compressor
Defective
Defective valve coil
indoor unit
electronic
expansion Defective valve body
valve
Defective gas pipe
thermistor of indoor unit
Defective
control
Defective liquid pipe
thermistor of indoor unit
Defective main PCB
Dirty evaporator
Decreased
fan output
Decreased
airflow rate
High
airflow
passage
resistance
←Refer to CHECK 6 .
←
Are the coil resistance and
insulation normal?
←Is the connector properly connected?
Are the thermistor resistance
characteristics normal?
←Is the connector properly connected?
Are the thermistor resistance
characteristics normal?
←Does the heat exchanger get clogged?
←Can the fan motor be rotated
Defective fan motor
with hands?
Are the motor coil resistance and
insulation normal?
Defective main PCB
(including capacity
setting)
←Is the air filter clogged?
Dirty filter
←Is there any obstacle in the
Obstacles
airflow passage?
Part 6 Service Diagnosis
SiAF332111E