Check - Daikin VRV II-Q RQYQ8-48PY1B Service Manual

SiBE341027

2.43 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 outside unit electronic
expansion valve is throttled:
(See
Rise in high
pressure
Defective high
pressure
control
[In heating]
If the indoor unit electronic
expansion valve is excessively
throttled:
∗
(See 2.)
[In cooling]
High suction
air
temperature
of the
condenser
Degradation in
condensing
capacity
Refrigerant overcharge
Improper model selection
∗
1: In cooling, it is normal if the outside unit electronic expansion valve is fully open.
∗
2: In heating, the indoor unit electronic expansion valve is used for "subcooled degree control".
(For details, refer to "Electronic Expansion Valve Control".)
Service Diagnosis
High pipe
resistance
Defective outside
unit electronic
expansion valve
∗
1.)
A temperature di f ference i n excess of 10°C 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
High suction air
temperature of
indoor unit
High suction air
temperature of
indoor unit
Defective suction air thermistor of indoor unit
[In heating]
High suction air temperature of outside unit
Defective outdoor air temperature thermistor of outside unit
Dirty condenser
Mixing of non-condensable gas
Decreased
fan airflow
rate
[In heating]
Troubleshooting by Remote Controller
←
Stop valve closed
←
Bent or crashed pipe
←
Clogging of foreign particles
←
Defective valve coil
Defective valve body
←
Defective high pressure sensor
←
Defective service monitor PCB
←
Defective valve coil
Defective valve body
←
Defective high pressure sensor
←
Defective indoor unit
liquid pipe thermistor
←
Defective service monitor PCB
←
Short circuit
←
High outdoor air temperature
←
Short circuit
←
High outdoor air temperature
←
←
←
←
Is the heat exchanger clogged? (In cooling)
←
Is air or else mixed in the refrigerant system?
Defective
fan motor
Decreased
fan output
Defective
service monitor
PCB (Including
capacity setting)
Dirty filter
High air
passage
resistance
Obstacle
←
Refer to "F6" troubleshooting.
←
Is the indoor unit too small compared to
the large-sized outside unit?
Check to be sure the stop valve is open.
Conduct visual checks for pipe conditions.
Is there any temperature difference caused
before and after the filter or branch pipe.
Are the coil resistance and insulation normal?
Are the electrical characteristics normal?
Is the pressure value checked with the Service Checker
corresponding to the measurement of the pressure sensor?
Are the coil resistance and insulation
normal?
Are the electrical characteristics normal?
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Is the pressure value checked with the
Service Checker corresponding to the
measurement of the pressure sensor?
Is the suction air temperature not more
than 43°C?
Is the outdoor air temperature not more
than 43°C?
Is the suction air temperature not more
than 27°C?
Is the indoor temperature not more than 27°C?
Is the connector properly connected?
Are the thermistor resistance
characteristics normal?
Is the outdoor air temperature not more
than 16°CWB?
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?
179