Check - Daikin VRV-WIII RWEYQ72PTJU Service Manual

SiUS30-1301

3.51 Check

CHECK 1

Check for Causes of Rise in High Pressure
Referring to the Fault Tree Analysis (FTA) shown below, probe the defective points.
Local
pressure
rise
[In cooling]
If the condensing unit
electronic expansion valve is
throttled: (See 1.)
Rise in high
pressure
Defective high
pressure
control
[In heating]
If the indoor unit electronic
expansion valve is excessively
throttled:
(See 2.)
High suction
air
temperature
of the
condenser
Degradation
incondensing
capacity
Refrigerant overcharge
Improper model selection
1: In cooling, it is normal if the condensing unit electronic expansion valve is fully open.
Note:
2: In heating, the indoor unit electronic expansion valve is used for Subcooling Degree Control.
Service Diagnosis
High pipe
resistance
Defective condensing
unit electronic
expansion valve
A temperature di f ference i n excess of 18°F between the
i n l e t and the outl e t i s deemed to be abnormal .
Defective
control
Defective indoor
unit electronic
expansion valve
Defective
control
[In cooling]
High suction air
temperature of
indoor unit
High suction air
temperature of
indoor unit
Defective suction air thermistor of condensing
[In heating]
High suction air temperature of
Defective outdoor air temperature thermistor of condensing unit
Dirty condensing
Mixing of non-condensable gas
Decreased
fan airflow
rate
[In heating]
(For details, refer to Electronic Expansion Valve Control.)
Troubleshooting by Indication on the Remote Controller
 Check to be sure the stop valve is open.
Stop valve closed
 Conduct visual checks for pipe conditions.
Bent or crashed pipe
 Is there any temperature difference caused
Clogging of foreign particles
 Are the coil resistance and insulation normal?
Defective valve coil
Defective valve body
 Are the electrical characteristics normal?
Defective high pressure sensor
 Is the pressure value checked with the Service Checker
Defective control PCB
 Are the coil resistance and insulation
Defective valve coil
Defective valve body
 Are the electrical characteristics normal?
Defective high pressure sensor
 Is the connector properly connected?
Defective indoor unit
liquid pipe thermistor
 Is the pressure value checked with the
Defective control PCB
Short circuit
High outdoor air temperature High outdoor air temperature
Short circuit
High outdoor air temperature
unit
unit
condensing
 Is the heat exchanger clogged? (In cooling)
 Is air or else mixed in the refrigerant system?
Defective
fan motor
Decreased
fan output
Defective
control PCB
(Including
capacity setting)
Dirty filter
High air
passage
resistance
Obstacle
F6
 Refer to "
 Is the indoor unit too small compared to
the large-sized condensing unit?
before and after the filter or branch pipe.
corresponding to the measurement of the pressure sensor?
normal?
Are the thermistor resistance characteristics normal?
Service Checker corresponding to the
measurement of the pressure sensor?
 Is the suction air temperature not more
than 109.4°F?
 Is the outdoor air temperature not more
than 109.4°F?
 Is the suction air temperature not more
than 80.6°F?
 Is the indoor air temperature not more than 80.6°F?
 Is the connector properly connected?
Are the thermistor resistance
characteristics normal?
 Is the outdoor air temperature not more
than 60.8°FWB?
 Is the connector properly connected?
Are the thermistor resistance
characteristics normal?
 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 air passage?
" troubleshooting.
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