11
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 or switches
itself off
Power failure, under-
voltage
Does all other electrical
equipment function cor-
rectly?
Check voltage and if neces-
sary wait until turned on
again
Defective mains fuse/main
switch turned off
Are all lighting circuits func-
tioning correctly?
Replace the mains fuse.
Close main circuit breaker
Damaged power supply
Does all other electrical
equipment function cor-
rectly?
Repair by specialist firm
Malfunction of the external
condensate pump
Has the pump shut down
due to a malfunction?
Check the pump and clean
it if necessary
Regulation not activated
Has the operating mode /
controller been correctly
set?
Check the setting and oper-
ation
Electrical surges caused by
thunderstorms
Have there been lightning
strikes in the area recently?
Switch off the mains
breaker and switch it back
on. Have it inspected by a
specialist
The unit is run-
ning but only pro-
vides reduced or
no cooling or
heating capacity
Valve assembly jammed,
not working, not yet fully
activated
Is electrical power present
at the valve head or has the
time period of 3 minutes
after activation passed?
Have the valve head
replaced or wait for time
period to pass
Filter is dirty/air inlet/outlet
opening is blocked by
debris
Have the filters been
cleaned?
Clean the filters
Windows and doors open.
Heating/cooling load has
increased
Have structural/usage mod-
ifications been made?
Close windows and doors/
install additional units
Cooling mode is not set
Does the "cooling" symbol
appear on the display?
Correct the settings for the
unit
Medium temperature in
cooling mode too high
Is the inlet temperature
approx. + 5 - + 10 °C and is
the circulation pump
working?
Reduce the medium tem-
perature
Medium temperature in
heating mode too low
Is the inlet temperature
approx. + 24 - + 45 °C and
is the circulation pump
working?
Increase the medium tem-
perature
29
Summary of Contents for KWK 135 EC
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