Appendix
0020291544_01 Hydraulic Station Installation and maintenance instructions
51
Statuscode
Meaning
S.256 Fan unit 1: Air inlet
temp. too low
The compressor does not start because the outdoor temperature at the fan is below the operating
limits. Heating mode: < -20 °C. Domestic hot water mode: < -20 °C. Cooling mode: < 15 °C.
S.260 Fan unit 2: Fan blocked
If the fan speed is 0 rpm, the heat pump is switched off for 15 minutes and then restarted. If the fan
does not start up after four unsuccessful restarts, the heat pump is switched off and the fault mes-
sage
F.785
is displayed.
S.272 Building circuit: Re-
maining feed head limit active
The remaining feed head that is set under the configuration is reached.
S.273 Building circuit: Flow
temperature too low
The flow temperature that is measured in the building circuit is below the operating limits.
S.275 Building circuit: Flow
rate too low
Building circuit pump defective. All consumers in the heating system are closed. The values fall below
the specific minimum volume flows. Check that the dirt filter is permeable. Check the stopcocks and
thermostatic valves. Ensure that the flow rate is at least 35% of the nominal flow rate. Check that the
building circuit pump functions correctly.
S.276 Building circuit: Lock-
out contact S20 open
Contact S20 is open at the heat pump's main PCB. Incorrect limit thermostat setting. Flow temper-
ature sensor (heat pump, gas-fired boiler, system sensor) measures values that deviate downwards.
Adjust the maximum flow temperature for the direct heating circuit via the system control (observe
the upper switch-off threshold for the boilers). Adjust the set value for the limit thermostat. Check the
sensor values
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 thermal energy is available from the building cir-
cuit.
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 thermal 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 operating limit, the heat pump is switched off for
15 minutes and is then restarted again. If the pressure remains too high after four unsuccessful re-
starts, 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.
