Daikin VRV III REYQ8PY1, Service Manual

Page: 359 / 452

Troubleshooting (OP: Unified ON/OFF Controller) Si37-701
348 Troubleshooting
[CHECK 3] Check the Factors of Overheat Operation
Identify the defective points referring to the failure factor analysis (FTA) as follows.
Irregular piping length
Bend/collapse
(Including moisture choke)
Stop valve is closed.
4 way switch valve is in the
middle position.
Leak from hot gas bypass
valve
Subcooling
motor
operated
valve failure
Control
failure
Defective valve coil
Defective control PC board
Defective valve body
Defective valve coil
Defective valve body
Defective low pressure
sensor
Defective thermister for
suction pipe
Defective control PC board
Defective thermister for
indoor unit gas pipe
Defective thermister for
indoor unit liquid pipe
∗
1: Refer to “Low pressure protective control” (P126) for hot gas bypass control.
∗
2: Refer to P108 for subcooling electronic expansion valve control.
∗
3: “Superheating temperature control” in cooling mode is conducted by indoor unit electronic expansion valve. (Refer to P141)
∗
4: Superheating temperature control in heating mode is conducted by outdoor unit electronic expansion valve (EVM).
(Refer to P108).
∗
5: Judgment criteria of superheat operation:
Suction gas superheating temperature: 10 degrees and over. Discharge gas superheating temperature: 45 degrees
and over, except for immediately after starting and drooping control, etc..
(Use the above stated values as a guide. Depending on the other conditions, the unit may be normal despite the values
within the above scope.)
←
Check if coil resistance and insulation
are normal.
←
Check if coil resistance and
insulation are normal.
←
Check if the voltage property is
normal.
←
Check if the connector is connected properly.
Check if the thermister resistance property
is normal.
←
Check if the piping temperature connected
to the 4 way switch valve is normal.
←
Check if the pressure value given by the
service checker corresponding to actual
measurement value by the sensor.
←
Check if coil resistance and insulation are
normal.
←
Check if the connector is connected properly.
Check if the thermister resistance property is
normal.
←
Check if the connector is connected properly.
Check if the thermister resistance property is
normal.
←
Check if the connector is connected properly.
Check if the thermister resistance property is normal.
←
Check if coil resistance and insulation are
normal.
←
Check if the voltage property is normal.
←
Refer to [Check 7]
←
Check if the pressure value given by the
service checker corresponding to actual
measurement value by the sensor.
←
Does the piping length fall in the permissible range?
←
Corduet visual checks.
←
Remove the moisture by vacuum break. (Refer to [Check 8])
←
Check if the stop valve is open.
Faulty
discharge
pipe
temperature
control
Faulty hot
gas bypass
control
Hot gas circuit clogging
Defective solenoid
valve coil
Defective solenoid
valve body
Defective control PC board
Defective control
PC board
Defective valve coil
Defective low
pressure sensor
Defective subcool
heat exchange
outlet thermister
Defective valve
body
Faulty
subcooling
motorized
valve control
(EV2)
Superheat due to
shaft damage
Superheat due to
defective compressor
Indoor unit
motorized
valve failure
Faulty control
Faulty control
Outdoor unit
motorized
valve failure
Faulty of 4 way
switch valve
operation
[In cooling mode only]
(
∗
1)
(
∗
2)
Compressor
overheat
Refrigerant gas
shortage
Large resistance
of piping
Faulty
superheated
degree
control.
[In cooling mode]
When indoor unit
electronic
expansion valve
becomes too
narrow (
∗
3)
[In heading
mode]When
outdoor unit
electronic
expansion valve
becomes too
narrow (
∗
4)
Temperature
increase of
discharge
pipe