Check; High Pressure Check - Daikin VRV Aurora RXLQ-TATJU Series Service Manual

Check

4. Check
4.1

High Pressure Check

CHECK 1
Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points.
Rise in high
pressure
[In heating]
If the indoor unit electronic
expansion valve excessively
throttled:
(2.)
Note(s)
1. In cooling, it is normal if the outdoor unit electronic expansion valve (main) is fully open.
2. In heating, the indoor unit electronic expansion valve is used for subcooling degree control.
Reference
CHECK 6 Refer to page 377.
367
Local
High pipe
pressure
resistance
rise
[In cooling]
If the outdoor unit electronic Defective outdoor
unit electronic
expansion valve is throttled:
expansion valve
(1.)
A temperature difference
in excess of 10°C (18°F) between
the inlet and the outlet is deemed
to be abnormal.
Defective
control
Defective
high pressure
Defective indoor
control
unit electronic
expansion valve
Defective
control
[In cooling]
High suction air
temperature of
High suction
outdoor unit
air
temperature
of the High suction
condenser air temperature
of indoor unit
Defective suction air thermistor of indoor unit
[In heating]
High suction air temperature of outdoor unit
Defective outdoor air temperature thermistor of outdoor unit
Degradation
Dirty condenser
in condensing
capacity
Mixing of non-condensable gas
Decreased
airflow rate
Excessive refrigerant charging
Improper model selection [In heating]
Stop valve closed
Check to be sure the stop valve is open.
Bent or crashed pipe Conduct visual checks for pipe conditions.
Clogging of foreign Is there any temperature difference caused before
materials and after the filter or branch pipe?
Are the coil resistance and insulation normal?
Defective valve coil
Defective valve body
Is the pressure value checked with the Service Checker
Defective high pressure sensor
corresponding to the measurement value of the pressure sensor?
Defective outdoor
Are the voltage characteristics normal?
unit main PCB
Defective valve coil
Are the coil resistance and insulation normal?
Defective valve body
Defective high pressure sensor
Is the pressure value checked with the Service Checker
corresponding to the measurement value of
the pressure sensor?
Defective indoor unit
liquid pipe thermistor
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Defective outdoor
Are the voltage characteristics normal?
unit main PCB
Is the suction air temperature less than 43°C (109.4°F)?
Short circuit
High outdoor air
Is the outdoor air temperature less than 43°C (109.4°F)?
temperature
Short circuit
Is the suction air temperature less than 27°C (80.6°F)?
High room
temperature Is the room temperature less than 27°C (80.6°F)?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Is the outdoor air temperature less than 16°CWB
(60.8°FWB)?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Is the heat exchanger clogged? (In cooling)
Is air or else mixed in the refrigerant system?
Defective fan
Decreased motor
fan
output
Defective outdoor unit
main PCB (Including
capacity setting)
High
Dirty filter
airflow
passage
Obstacle
resistance
Refer to CHECK 6.
Is the indoor unit too small compared to
the large-sized outdoor unit?
SiUS341802EC
Can the fan motor be rotated with hands?
Are the motor coil resistance and
insulation normal?
If a spare PCB is mounted, is the capacity
setting properly made?
Is the air filter clogged?
Is there any obstacle in the airflow passage?
Part 6 Service Diagnosis