Appendix
52
Installation and maintenance instructions flexoTHERM exclusive 0020196687_03
Code
Meaning
Cause
Remedy
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
switched the pump off as a securing
measure.
–
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
F.789
Sensor fault: Fan unit 2 fan inlet
temp.
–
Sensor not connected or sensor
input has short-circuited
–
Check the sensor in the fan unit, and
replace if necessary
–
Replace the cable harness in the fan
unit
F.790
Sensor fault: Fan unit 2 brine flow
temp.
–
Sensor not connected or sensor
input has short-circuited
–
Check the sensor in the fan unit, and
replace if necessary
–
Replace the cable harness in the fan
unit
F.792
Sensor fault: VI inlet temp.
–
Sensor not connected or sensor
input has short-circuited
–
Check the sensor, and replace if
necessary
–
Replace the cable harness
F.793
Sensor fault: EEV-VI outlet temp.
–
Sensor not connected or sensor
input has short-circuited
–
Check the sensor, and replace if
necessary
–
Replace the cable harness
F.797
Sensor fault: Cooling flow temp.
–
Sensor not connected or sensor
input has short-circuited
–
Check the sensor, and replace if
necessary
–
Replace the cable harness
F.798
Sensor fault: Well inlet temp.
–
Sensor not connected or sensor
input has short-circuited
–
Check the sensor, and replace if
necessary
–
Replace the cable harness
F.799
Sensor fault: Well outlet temp.
–
Sensor not connected or sensor
input has short-circuited
–
Check the sensor, and replace if
necessary
–
Replace the cable harness
F.1100
Immersion heater: Safety cut-out
open
The safety cut-out on the electric back-
up heater is open due to:
–
Insufficient volume flow or air in the
building circuit
–
Heating rod operation when the
building circuit is not filled
–
Heating rod operation at flow tem-
peratures above 110 °C trips the
safety fuse of the safety cut-out and
requires that the fuse be replaced
–
Feeding of external heat into the
building circuit
–
Check the circulation in the building
circuit pump
–
If required, open the stopcocks. The
safety cut-out is automatically reset
as soon as the temperature at the
fuse falls below 55 °C again.
Also press
reset
.
If the safety cut-out is still open at an
electric back-up heater temperature
below 55 °C, temperatures above
110 °C were reached and the safety
fuse tripped.
–
Replace the safety cut-out
–
Reduce or stop the external heat
that is entering
F.1117
Compressor: Phase failure
–
In-rush current limiter defective or
incorrectly connected
–
Defective fuse
–
Poorly tightened electrical connec-
tions
–
Mains voltage too low
–
Compressor/low tariff power supply
not connected
–
Blocked by energy supply company
for over three hours
–
Check the fuse
–
Check the electrical connections
–
Measure voltage at the heat pump
electrical connection
–
Reduce energy supply company
anti-cycling time to under three hours
F.1118
Compressor: Incorrect phase seq.
–
Incorrect order of phase connection
to the grid feed-in
–
In-rush current limiter defective or
incorrectly connected
–
Change the phase order by switch-
ing over two phases at a time on the
grid feed-in
–
Check the in-rush current limiter
