Error code
Description
Possible cause
Check/solution
False flame signal
Ionisation current measured
but no flame should be
present
Ignition transformer defec
tive
Defective gas valve
The burner remains very
hot: O
2
/CO
2
too high
Check the ionisation/ignition electrode
Check the gas valve and replace if neces
sary
Adjust O
2
/CO
2
settings
Gas valve error SU PCB
Bad connection
Defective SU PCB
Check the wiring
Check the SU PCB and replace if necessa
ry
Fan operation error
Bad connection
Fan defective
Check the wiring
Replace the fan if necessary
Check for adequate draw on the chimney
connection
Flow and return reversed
Bad connection
Sensor failure
Sensor not connected or in
correctly connected
Flow direction incorrect
Replace the sensor if necessary
Check the flow (direction, pump, valves)
Check that the sensors are operating cor
rectly
Check that the sensor has been fitted prop
erly
5x flame loss
No ionisation current
Vent the gas supply to remove air
Check that the gas valve is fully opened
Check the gas supply pressure
Check the operation and setting of the gas
valve unit
Check that the air supply inlet and flue gas
outlet are not blocked
Check that there is no recirculation of flue
gases
Communication error with the
SU PCB
Bad connection
Check whether the SU PCB has been correct
ly fitted in the connector on the PCU PCB
Communication error with the
SCU PCB
Bad connection
Defective SCU PCB
Check the wiring
SCU Replace PCB
Blocking input in locked-out
mode
Bad connection
External cause
Incorrectly set parameter
Check the wiring
Remove external cause
Check parameters
If present: HRU test fault
Bad connection
External cause
Incorrectly set parameter
Check the wiring
Remove external cause
Check parameters
11.2 Error memory
The boiler control unit has an error memory. It stores the last 16 errors that
have occurred.
In addition to the error codes, the following data is also saved:
Number of times that the error occurred: (
).
Boiler operating mode (
).
The flow temperature (
) and the return temperature (
)
when the error occurred.
To view the error memory, you must first enter the access code
.
11 Troubleshooting
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