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Code/meaning
F.585
The signal for the temperature
sensor at the condenser out-
let in the refrigerant circuit is in-
valid.
F.703
Refrigerant circuit low-pressure
sensor signal invalid
F.718
Environment circuit fan 1 is
blocked
F.727
High-pressure monitoring has
triggered in the refrigerant cir-
cuit
F.729
The temperature at the com-
pressor outlet is too low.
F.731
High-pressure switch has been
triggered
F.732
Compressor outlet temperature
too high
F.733
Evaporation temperature too
low
260
Possible cause
Temperature sensor at the con-
denser outlet is defective or not
connected
Low-pressure sensor not con-
nected or sensor input has
short-circuited
Fan does not rotate.
The compressor outlet temper-
ature is above 130 °C: Applica-
tion limits exceeded.
The electronic expansion valve
does not open correctly or does
not work.
Refrigerant volume too low due
to frequent defrosting as a res-
ult of extremely low evaporation
temperatures
The compressor outlet tem-
perature is lower than 0 °C for
more than 10 minutes or the
compressor outlet temperat-
ure is lower than -10 °C even
though the heat pump is in the
operating characteristics.
Refrigerant pressure too high.
The integrated high-pressure
switch in the outdoor unit has
tripped at 41.5 bar (g) or
42.5 bar (abs). Insufficient
energy output via the condenser
The compressor outlet temper-
ature is above 130 °C: Applic-
ation limits exceeded, EEV is
not working or does not open
correctly, refrigerant volume too
low, (frequent defrosting due to
extremely low evaporation tem-
peratures)
Insufficient air volume flow
through the outdoor unit's heat
exchanger (heating mode)
leads to an insufficient energy
input in the environment circuit
(heating mode) or building cir-
cuit (cooling mode). Refrigerant
volume too low.
Measure
▶
Check: Plug, wiring harness, sensor, PCB.
▶
Check: Low-pressure sensor (resistance measurement based
on sensor characteristic values), wiring harness.
▶
Check: Air route (blockage), F1 fuse on the PCB in the fan unit
(OMU).
1.
Check whether heat emission is possible.
2.
Check whether all single-room valves and isolation valves
are open.
3.
If fans are installed in the heating installation, check whether
these run in heating mode.
4.
Check the temperature sensors' compressor inlet and outlet.
5.
Check the condenser outlet temperature sensor (TT135).
1.
Check the electronic expansion valve (does the EEV move
to the limit stop?). Use the sensor/actuator test.
2.
Replace the electronic expansion valve.
1.
Check the refrigerant volume (see Technical data).
2.
Check the tightness of the refrigerant circuit.
3.
Check whether the service valves on the outdoor unit are
open.
1.
Check the high-pressure sensor.
2.
Check that the EEV functions correctly.
3.
Check the condenser outlet temperature sensor
(undercooling).
4.
Check whether the 4-port diverter valve is in the intermedi-
ate position.
5.
Check the refrigerant volume for overfilling.
1.
Purge the building circuit.
2.
Too low a volume flow as a result of closing single room
controls in an underfloor heating system.
3.
Check that the dirt filter that is in place is permeable.
4.
Refrigerant flow rate too low (e.g. electronic expansion valve
defective, 4-port diverter valve is mechanically blocked, filter
is blocked). Inform customer service.
5.
Cooling mode: Check the fan unit for dirt.
6.
Check the high-pressure switch and high-pressure sensor.
7.
Reset the high-pressure switch and carry out a manual reset
on the product.
1.
Check the compressor inlet sensor and outlet sensor.
2.
Check the condenser outlet temperature sensor (TT135).
3.
Check the EEV (does the EEV move to the limit stop? Use
the sensor/actuator test).
4.
Check the refrigerant volume (see Technical data).
5.
Carry out a leak-tightness test.
6.
Check whether the service valves on the outdoor unit are
open.
1.
If the building circuit contains thermostatic valves, check that
they are suitable for cooling mode (check volume flow in
cooling mode).
2.
Check the fan unit for dirt.
3.
Check the EEV (does the EEV move to the limit stop? Use
the sensor/actuator test).
4.
Check the compressor inlet sensor.
5.
Check the refrigerant volume.
Installation and maintenance instructions 8000017440_FT
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