13
Troubleshooting and customer service
The unit and components are manufactured using state-of-the-art production methods and tested several
times to verify that they function correctly. However, if malfunctions should occur, please check the functions
as detailed in the list below. For systems with an indoor unit and outdoor unit, refer to the chapter "Trouble-
shooting and customer service" in both operating manuals. Please inform your dealer if the unit is still not
working correctly after all function checks have been performed!
Operational malfunctions
Malfunction
Possible causes
Checks
Remedial measures
The unit does not
start
Display is not illuminated.
No power supply, power
failure, device fuse / main
switch switched off / defec-
tive
Check the power connec-
tions on the general supply
terminals and the voltage
values. Check the unit fuse,
the main switch and the
fuses on the secondary side
of the additional trans-
former.
The display lights up and
shows “Phase sequence
error”.
Incorrect phase sequence.
The phase sequence relay
did not issue an enable
signal.
Swap the phase conductors
of the power supply on the
terminal block on the con-
trol panel.
Display shows status: “Off”.
The unit is deactivated.
Change the operating
status in the “A. On / Off
Unit” submenu
The controller emits an
acoustic signal.
One or more protective
devices have tripped. A
malfunction is present.
Check error messages, rec-
tify the malfunction,
acknowledge the malfunc-
tion (see chapter “Error indi-
cation”).
The compressor icon is dis-
played, but the unit does
not start.
Compressor or compressor
contactor defective.
Have specialist replace
contactor or compressor.
The unit works at
reduced cooling
capacity
Thermal load too high.
Thermal load was
increased.
If possible, reduce the
thermal load.
Inlet temperature too high.
Return flow temperature set
too high.
Reduce return temperature.
Air in the medium cycle.
Medium cycle not bled, no
automatic bleeding valves
installed.
Manually bleed or install
automatic bleeding valves
at the highest point.
Condenser temperature too
high.
Slats dirty, exposed to
strong sunlight.
Clean fins, provide shade
for the unit, adhere to oper-
ating limits.
Pulse mode because of too
little demand.
System may be over-
dimensioned
Increase medium flow rate
with the installation of a
storage tank.
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