Check; High Pressure Check - Daikin VRV RXYMQ-A Series Service Manual

SiME332106E

6. Check

6.1

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
2. In heating, the indoor unit electronic expansion valve is used for subcooling
Reference
CHECK 6 Refer to page 278.
Part 6 Service Diagnosis
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 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
High suction
of the
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]
open.
degree control.
mCheck to be sure the stop valve is open.
Stop valve closed
mConduct visual checks for pipe conditions.
Bent or crashed pipe
mIs there any temperature difference caused before
Clogging of foreign
and after the filter or branch pipe?
materials
mAre the coil resistance and insulation normal?
Defective valve coil
Defective valve body
mIs the pressure value checked with the Service Checker
Defective high pressure sensor
corresponding to the measurement value of the pressure sensor?
Defective main
mAre the voltage characteristics normal?
PCB
mAre the coil resistance and insulation
Defective valve coil
normal?
Defective valve body
mIs the pressure value checked with the Service
Defective high pressure sensor
Checker corresponding to the measurement value of
the pressure sensor?
Defective indoor unit
mIs the connector properly connected?
liquid pipe thermistor
Are the thermistor resistance characteristics normal?
Defective main
mAre the voltage characteristics normal?
PCB
mIs the suction air temperature more than 43qC?
Short circuit
High outdoor air
mIs the outdoor air temperature more than 43qC?
temperature
mIs the suction air temperature more than 27qC?
Short circuit
High room
mIs the room temperature more than 27qC?
temperature
mIs the connector properly connected?
Are the thermistor resistance characteristics normal?
mIs the outdoor air temperature more than 16qCWB?
mIs the connector properly connected?
Are the thermistor resistance characteristics normal?
mIs the heat exchanger clogged? (In cooling)
mIs air or else mixed in the refrigerant system?
Defective fan
mCan the fan motor be rotated with hands?
Decreased
motor
fan
output
Defective main
PCB (Including mIf a spare PCB is mounted, is the capacity
capacity setting)
mIs the air filter clogged?
High Dirty filter
airflow
passage
mIs there any obstacle in the airflow passage?
resistance
Obstacle
mRefer to CHECK 6 .
mIs the indoor unit too small compared to
the large-sized outdoor unit?
Are the motor coil resistance and
insulation normal?
setting properly made?
Check
271