Technical data

Table Of Contents
FAULTS
6 720 803 687 (2012/11)68
UL Low pressure fault
Fault “UL” is shown if the following
conditions are met for 3 minutes in
10 following compressor start in
heating mode.
•TH7 - TH3 4 K
TH5 - Room temperature 2K.
This means:
TH3: liquid line temperature in the
external unit in °C.
TH5: evaporator/condenser
temperature in the internal unit in
°C.
TH7: outside temperature in °C.
Shut-off valves closed. Open shut-off valves.
Insufficient refrigerant or leak. Check amount of refrigerant and additional charge.
Check pipe system for leaks and eliminate any leaks.
Check increased heat through superheating.
Faulty linear expansion valve (LEV). Check linear expansion valve (LEV).
Refrigerant circuit blocked by foreign objects or
contaminated by water.
Vacuum out refrigerant.
Subject the refrigerant circuit to the vacuum for at least one
hour to remove the water.
Refill with clean refrigerant.
UP Compressor overcurrent — safety
device has responded
If the protective equipment is
tripped 30 seconds after the
compressor start due to DC
overcurrent, fault display “UP” is
shown.
Ball valve closed in operation. Check and completely open all ball valves.
Reduced supply voltage (mains side). Check supply voltage (mains side).
Poor connection/contacts or terminal loose on
compressor supply cables.
Check and correct compressor wiring.
Fan faulty. ▶Check fan.
Air short circuit on internal or external unit. Eliminate air short circuit.
Faulty input circuit (voltage) on the external unit
PCB.
Replace faulty PCB.
Faulty compressor. Check compressor and replace external unit if required.
Inverter board faulty. Replace faulty PCB.
DIP switch settings incorrect on the external unit
PCB.
Check DIP switches and correct settings.
E6 Signalling error between the
internal and external units
(reception error)
The internal unit cannot receive any
signals within 6 minutes from start
or after 3 minutes in operation. Fault
display “E6” is shown.
Poor connection/contacts or terminal loose on the
control cables, cable break.
Check and correct wiring for all control cables between
internal and external unit.
Faulty transmitter/receiver circuit on external unit
PCB.
Check whether the fault display E6 will still be issued after a
restart.
Check PCBs of the internal and external units and replace if
faulty.
Faulty transmitter/receiver circuit on internal unit
PCB.
Noise in the control cables.
Fan motor faulty. Isolate the external unit from the power supply, and undo
terminal CNF1 on the fan motor. Restart external unit.
Replace fan motor if the fault message is no longer
displayed.
Replace the external unit PCB if the fault message
continues to be displayed.
Faulty starting current limiter on the external unit
PCB.
Check starting current limiter and replace if required.
E7 Signalling error between the
internal and external units
(transmission error)
Fault display “E7” will be shown if it
has been recognised 30 times that
“1” is being received constantly,
however the internal unit sends “0”.
Faulty transmitter/receiver circuit on internal unit
PCB.
Check whether the fault display E7 will still be issued after a
restart.
Check PCBs of the internal and external units and replace if
faulty.
Noise in the voltage system.
Noise in the control cables.
E8 Communication error between
internal and external unit —
reception error
If the external unit cannot receive
any signals within 3 minutes, fault
display “E8” is shown.
Poor connection/contacts or terminal loose on the
control cables, cable break.
Check and correct wiring for all control cables between
internal and external unit.
Faulty transmitter/receiver circuit on external unit. Switch the supply voltage off and on again (reset system).
Check if fault display “E8” is shown again after the restart.
Check PCBs of the internal and external units and replace if
faulty.
Faulty transmitter/receiver circuit on internal unit.
Noise in the control cables.
Code Description Cause Possible solution / check
Table 39 Fault indications, external unit