OPERATING AND INSTALLATION MANUAL HEAT PUMP COMBI UNIT PKOM4 PAGE 53
USER
GENERALSPECIALIST PERSONNEL
48
Safety chain
heating/cooling
compressor
High-pressure switch in the
"heating/cooling" cooling
circuit has been activated.
Compressor is running out-
side of its operating limits.
Check air volume flow on the supply side, as in the
case of errors 28 and 30
Error correction as in the case of errors 28
and 30
Check terminals on frequency inverter T1 Restore terminal contacts
Check the connection on pressure switch B36 Restore contact
Check cable W65 Replace cable W65
Check pressure switch B36 using a measuring
device, pull the plugs on pressure switch B6 and
measure the resistance. The pressure switch must
be uninterrupted in its normal state (NC) PLEASE
NOTE: The pressure in the "heating/cooling" cool-
ing circuit must be below 20bar!
Replace the pressure switch
Too much refrigerant in the "heating/cooling"
cooling circuit
Extract cooling circuit and refill with cooling
medium
No error detectable Please contact your service partner
Check air volume flow on the supply side, like with errors 28 and 30
Overtemperature thermostat
on the "heating/cooling"
compressor has been activat-
ed. Compressor is running
outside of its operating limits.
Check terminals on frequency inverter T1 Restore terminal contacts
Check the connection on overtemperature ther-
mostat F4
Restore contact
Check cable W65 Replace cable W65
Check pressure switch B36 using a measuring
device, pull the plugs on overtemperature thermo-
stat F4 and measure the resistance. The pressure
switch must be uninterrupted in its normal state
(NC).
Replace the overtemperature thermostat F4
Not enough refrigerant in the "heating/cooling"
cooling circuit
Leakage search and correction in the "heat-
ing/cooling" cooling circuit
Evaporating temperature in the "heating/cooling"
cooling circuit too low
a) Check defrosting
b) Check air volume flow for extract/exhaust
air
No error detectable Please contact your service partner
49
FU Modbus
heartbeat error
Erroneous BUS communica-
tion between the main board
and the frequency inverter
Check frequency inverter T1 Replace frequency inverter T1
No error detectable Please contact your service partner
50 FU fatal error Fatal frequency inverter error
Check terminals H4 on main board N1 Restore terminal contacts
Check terminal H5 on heat pump board N3 Restore terminal contacts
Check terminals on frequency inverter T1 Restore terminal contacts
Check frequency inverter T1 Replace frequency inverter T1
No error detectable Please contact your service partner
51
Recurrent
FU error
Frequency inverter error that
has occurred 3 times during
the last hour
Check terminal M6 on heat pump board N3 Restore terminal contacts
Check terminals on frequency inverter T1 Restore terminal contacts
Check cable W63 Replace cable W63
Check whether a bus connection in heating/cool-
ing operation is established: LED on terminal M6
on heat pump board N3 is blinking
a) Replace heat pump board N3
b) Replace frequency inverter T1
Check frequency inverter T1 Replace frequency inverter T1
No error detectable Please contact your service partner
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