*****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
55
Code
Meaning
S.277 Building circuit: Pump
fault
If the building circuit pump is inactive, the heat pump is switched off for 10 minutes and is then restar-
ted. If the building circuit pump does not start up after three unsuccessful restarts, the heat pump is
switched off and the fault message
F.788
is displayed.
S.280 Freq. converter fault:
Compressor
The compressor motor or wiring is defective.
S.281 Freq. converter fault:
Mains voltage
There is overvoltage or undervoltage.
S.282 Freq. converter fault:
Overheating
If the cooling of the frequency inverter is not sufficient, the heat pump is switched off for one hour and
then restarted again. If the cooling is not sufficient after three unsuccessful restarts, the heat pump is
switched off and the fault message
F.819
is displayed.
S.283 De-icing time too long
If the de-icing takes longer than 15 minutes, the heat pump is restarted. If the time for the de-icing is
still not sufficient after three unsuccessful restarts, the heat pump is switched off and the fault mes-
sage
F.741
is displayed.
►
Check whether sufficient heat energy is available from the building circuit.
S.284 De-icing flow temperat-
ure too low
If the flow temperature is below 5 °C, the heat pump is restarted. If the flow temperature is still not
sufficient after three unsuccessful restarts, the heat pump is switched off and the fault message
F.741
is displayed.
►
Check whether sufficient heat energy is available from the building circuit.
S.285 Compressor outlet tem-
perature too low
Compressor outlet temperature is too low
S.286 Hot gas temperature
switch open
If the hot gas temperature is above 119 °C +5 K, the heat pump is switched off for one hour and then
restarted again. If the hot gas temperature has not fallen after three unsuccessful restarts, the heat
pump is switched off and the fault message
F.823
is displayed.
S.287 Fan 1: Wind
Before starting, the fan rotates at a speed of 50 rpm or higher. This may be caused by a strong out-
side wind.
S.288 Fan 2: Wind
Before starting, the fan rotates at a speed of 50 rpm or higher. This may be caused by a strong out-
side wind.
S.289 Current limit active
The outdoor unit's power consumption is reduced, the compressor speed is reduced. The com-
pressor's operating current exceeds the limit value that is set under the configuration. (for 3 kW,
5 kW, 7 kW units: <16 A; for 10 kW, 12 kW units: <25 A)
S.290 Switch-on delay active
The compressor's switch-on delay is active.
S.302 High-pressure switch
open
If the pressure in the refrigerant circuit exceeds the application limit, the heat pump is switched off
for 15 minutes and is then restarted again. If the pressure remains too high after four unsuccessful
restarts, the fault message
F.731
is displayed.
S.303 Compressor outlet tem-
perature too high
The operating characteristics have been exited. The heat pump is restarted.
S.304 Evaporation temperat-
ure too low
The operating characteristics have been exited. The heat pump is restarted.
S.305 Condensation temperat-
ure too low
The operating characteristics have been exited. The heat pump is restarted.
S.306 Evaporation temperat-
ure too high
The operating characteristics have been exited. The heat pump is restarted.
S.308 Condensation temperat-
ure too high
The operating characteristics have been exited. The heat pump is restarted.
S.312 Building circuit: Return
temperature too low
Return temperature in the building circuit too low for compressor to start. Heating: Return temperature
< 5 °C. Cooling: Return temperature < 10 °C. Cooling: Check that the 4-port diverter valve works cor-
rectly.
S.314 Building circuit: Return
temperature too high
Return temperature in the building circuit too high for the compressor to start. Heating: Return tem-
perature > 56 °C. Cooling: Return temperature > 35 °C. Cooling: Check that the 4-port diverter valve
works correctly. Check the sensors.
S.351 Immersion heater: Flow
temp. too high
The flow temperature at the immersion heater is too high. Flow temperature > 75 °C. The heat pump
is switched off.
S.516 De-icing mode active
The heat pump de-ices the outdoor unit's heat exchanger. The heating mode is interrupted. The max-
imum de-icing time is 16 minutes.
S.575 Frequency converter:
Internal fault
An internal electronics fault is present on the outdoor unit's inverter PCB. If this occurs three times,
fault message F.752 appears.
S.581 Connection fault: Fre-
quency converter not recog-
nised
Missing communication between the frequency converter and the outdoor unit's PCB. After this oc-
curs three times, fault message F.753 appears.
S.590 Fault: 4-port valve posi-
tion not correct
The 4-port diverter valve does not move fully to the heating or cooling position.
