Check For Causes Of Drop In Low Pressure - Daikin R71FUV1 Service Manual

Troubleshooting by Remote Controller
CHECK 15

Check for causes of drop in low pressure

Referring to the Fault Tree Analysis (FTA) shown below,
probe the defective points.
[In cooling]
Defective low
pressure
control
[In both
cooling and
heating]
(∗2)
[In cooling]
Abnormally
If the indoor
dropping low
unit electronic
pressure
expansion
(Low
valve is
evaporating
throttled too
temperature)
much:
(∗3)
Defective
electronic
expansion
valve control
[In heating]
If the outdoor
unit electronic
expansion
valve
excessively
throttled:
(∗4)
A
Defective
compressor
(∗1)
capacity
control
Defective low
pressure
protection
control
Defective
indoor unit
electronic
expansion
valve
Defective
control
Defective
outdoor unit
electronic
expansion
valve
Defective
control
← Are the electrical
Defective low
pressure characteristics normal?
sensor
← Is the pressure value
Defective
service
checked with the Service
monitor PCB Checker corresponding to
the measurement value of
the pressure sensor?
← Are the electrical
Defective low
pressure
characteristics normal?
sensor
Defective hot
← Are the coil resistance and
gas solenoid
insulation normal?
valve
← Is the pressure value
Defective
service
checked with the Service
monitor PCB
Checker corresponding to
the measurement value of
the pressure sensor?
← Are the coil resistance and
Defective
valve coil
insulation normal?
Defective
valve body
← Check for the thermistor
Defective gas
pipe thermistor
resistance and connection.
of indoor unit
← Check for the thermistor
Defective liquid
pipe thermistor
resistance and connection.
of indoor unit
← Is the pressure value
Defective
service
checked with the Service
monitor PCB
Checker corresponding to
the measurement value of
the pressure sensor?
← Are the coil resistance and
Defective
valve coil
insulation normal?
Defective
valve body
← Are the electrical
Defective low
pressure
characteristics normal?
sensor
← Check for the thermistor
Defective
suction pipe
resistance and connection.
thermistor
Defective
service
monitor PCB
Si20-701_B
485