*****INTERNAL*****30 R_D proof- 26.10.2022 / 09:15:46- VaillantGroup\DOC-agt\Brand\VIH_QW_190_6\ENG\OI-II_GB_0020291525
0020291525_04 Installation and maintenance instructions
57
Code
Meaning
Cause
Remedy
F.517
Sensor fault: Compr. outlet temp.
–
The sensor is not connected or the
sensor input has short-circuited
–
Check and, if required, replace the
sensor
–
Replace the wiring harness
F.519
Sensor fault: Building circuit re-
turn temp.
–
The sensor is not connected or the
sensor input has short-circuited
–
Check and, if required, replace the
sensor
–
Replace the wiring harness
F.520
Sensor fault: Building circuit flow
temp.
–
The sensor is not connected or the
sensor input has short-circuited
–
Check and, if required, replace the
sensor
–
Replace the wiring harness
F.526
Sensor fault: EEV outlet temp.
–
The sensor is not connected or the
sensor input has short-circuited
–
Check and, if required, replace the
sensor
–
Replace the wiring harness
F.546
Sensor fault: High pressure
–
The sensor is not connected or the
sensor input has short-circuited
–
Check the sensor (e.g. using an in-
stallation aid), and replace if neces-
sary
–
Replace the wiring harness
F.582
Fault: EEV
–
EEV is not connected correctly or
there is a cable break to the coil
–
Check the plug connections and, if
required, replace the coil from the
EEV
F.585
Sensor fault: Capac. outlet temp.
–
The sensor is not connected or the
sensor input has short-circuited
–
Check and, if required, replace the
sensor
–
Replace the wiring harness
F.703
Sensor fault: Low pressure
–
The sensor is not connected or the
sensor input has short-circuited
–
Checking the sensor (e.g. using an
installation aid), and replacing it if
necessary
–
Replace the wiring harness
F.718
Fan unit 1: Fan blocked
–
There is no confirmation signal stat-
ing that the fan is rotating
–
Check the air route and, if required,
remove any blockages
F.729
Compressor outlet temperature
too low
–
The compressor outlet temperature
is lower than 0 °C for more than 10
minutes or the compressor outlet
temperature is lower than -10 °C
even though the heat pump is in the
operating characteristics.
–
Checking the high-pressure sensor
–
Checking that the EEV is working
correctly
–
Check the condenser outlet temper-
ature sensor (supercooling)
–
Check whether the 4-port diverter
valve is in the intermediate position
–
Checking the refrigerant volume for
overfilling
F.731
High-pressure switch open
–
Refrigerant pressure too high. The
integrated high-pressure switch
in the outdoor unit has tripped at
31.5 bar (g) or 32.5 bar (abs)
–
Insufficient energy output via the
condenser
–
Purging the building circuit
–
Too low a volume flow as a result
of closing single room controls in an
underfloor heating system
–
Check that the dirt filter that is in
place is permeable
–
Refrigerant flow rate too low (e.g.
electronic expansion valve defective,
4-port diverter valve is mechanically
blocked, filter is blocked). Inform
customer service.
–
Cooling mode: Check the fan unit for
dirt
–
Check the high-pressure switch and
high-pressure sensor
–
Reset the high-pressure switch and
carry out a manual reset on the
product.
