Appendix
56
Installation and maintenance instructions Hydraulic Station 0020291544_01
Code
Meaning
Cause
Remedy
F.785
Fan unit 2: 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.788
Building circuit: Pump fault
–
The electronics system of the high-
efficiency pump has detected a
fault (e.g. dry running, blockage,
overvoltage, undervoltage) and has
switched off and locked the pump.
–
Switch the heat pump off for at least
30 seconds (no current)
–
Check the quality of the plug contact
on the PCB
–
Check that the pump functions cor-
rectly
–
Purging the building circuit
–
Check that the dirt filter that is in
place is permeable
F.817
Freq. converter fault: Compressor
–
Defect in the compressor (e.g. short
circuit)
–
Defect in the frequency converter
–
Connection cable to the compressor
is defective or loose
–
Measure the winding resistance in
the compressor
–
Measure the frequency converter
output between the three phases, (it
must be > 1 k
Ω
)
–
Check the cable harness and plug
connections
F.818
Freq. converter fault: Mains
voltage
–
Incorrect mains voltage for operating
the frequency converter
–
Shutdown via the energy supply
company
–
Measure and, if required, correct the
mains voltage
The mains voltage must be between
195 V and 253 V.
F.819
Freq. converter fault: Overheating
–
Internal overheating of the frequency
converter
–
Allow the frequency converter to cool
and restart the product
–
Check the frequency converter's air
route
–
Check that the fan is working cor-
rectly
–
The maximum environmental tem-
perature of the outdoor unit (46 °C)
has been exceeded.
F.820
Connection fault: Building circuit
pump
–
Pump does not report any signal
back to the heat pump
–
Check the cable to the pump for
defects and, if required, replace it
–
Replace the pump
F.821
Sensor fault: Immers. heater flow
temp.
–
The sensor is not connected or the
sensor input has short-circuited
–
Both of the flow temperature sensors
in the heat pump are defective
–
Check and, if required, replace the
sensor
–
Replace the cable harness
F.823
Hot gas temperature switch open
–
The hot gas thermostat shuts down
the heat pump if the temperature
in the refrigerant circuit is too high.
Following a waiting period, the heat
pump attempts to start once more.
After three failed start attempts
in succession, a fault message is
displayed.
–
Max. refrigerant circuit temperature:
110 °C
–
Waiting period: 5 mins (after it first
occurs)
–
Waiting period: 30 mins (after it
occurs a second time and any other
time after that)
–
The fault counter is reset if both of
the following conditions are met:
–
Heat requirement without switch-
ing off prematurely
–
60 mins uninterrupted operation
–
Check the EEV
–
Replace the dirt filter in the refrigera-
tion circuit, if required
