Fault finding and diagnosis
79
Greenstar 2000 – 6 721 820 552 (2021/02)
1019
Incorrect pump type detected
▶ Pump communication failure or wrong pump is fitted (non-ErP).
▶ Check the pump communication wire is connected and has continuity.
▶ Replace the pump for correct modulating pump.
1021 B
Cylinder charging or hot water temperature
sensor faulty
▶ Check the domestic hot water temperature sensor connected and the plug connected
to temperature sensor.
▶ Check the resistance of the temperature sensor and replace if required.
▶ Check the continuity of harness and replace if required.
1023 R
Maximum run time including standby time
reached
▶ Check the maintenance menu.
▶ Reset the maintenance code via the reset menu.
1025 –
Return temp. sensor is faulty
Not fitted on the boiler.
1037 W
Outside temp. sensor faulty - heating back-
up operation active
Tip: Check the weather compensation is applicable and the menu has not been accidently
switched on in the menu.
▶ Check the positioning of the outside weather sensor.
▶ Check the weather sensor connections on the control board.
▶ Check the resistance of the sensor and the continuity down the cable and replace if
required.
1068 W
Outside temp. sensor or lambda probe
faulty
▶ Check the outdoor sensor plug is connected.
▶ Check the resistance of the sensor and replace if required.
▶ Check the continuity of harness and replace if required.
▶ Replace the outdoor sensor.
1073 W
Short circuit of the flow temperature sensor ▶ Check the flow temperature sensor plug is connected.
▶ Check the resistance of the flow temperature sensor and replace if required.
▶ Check the continuity of harness and replace if required.
▶ Replace the flow temperature sensor.
1074 W
No signal from flow temperature sensor
▶ Check the flow temperature sensor plug is connected.
▶ Check the resistance of the flow temperature sensor and replace if required.
▶ Check the continuity of harness and replace if required.
▶ Replace the flow temperature sensor.
▶ Replace the PCB.
1075 W
Short-circuit heat exchanger temperature
sensor
▶ Check the temperature sensor plug is connected.
▶ Check the resistance of sensor and replace if required.
▶ Check the continuity of harness and replace if required.
▶ Replace the temperature sensor.
▶ Replace the PCB.
1076 W
No signal from heat exchanger temperature
sensor
▶ Replace the temperature sensor plug is connected.
▶ Check the resistance of sensor and replace if required.
▶ Check the continuity of harness and replace if required.
▶ Replace the temperature sensor.
▶ Replace the PCB.
2051 –
Internal fault
▶ Disconnect power from the system for 30 seconds.
▶ Check and replace control unit.
▶ Notify customer service.
2085 V
Internal fault
▶ Reset the appliance.
▶ Switch off the appliance for 30 s then turn back on.
▶ Check the incoming mains voltage.
▶ Check the polarity.
▶ Replace the PCB.
2908 V
System fault boiler electronics/basic
controller
▶ Restart the appliance to see if the problem re-occurs.
▶ If the fault remains after resetting: the burner controller (PCB) is defective and must be
replaced.
2909 –
System fault boiler electronics / basic
controller
▶ If the fault persists following a reset, the burner control unit or Key (including
interconnecting leads) is faulty and must be replaced.
2910 V
Fault in flue system
▶ Check the flue for obstructions and remove any found.
▶ Check the flue integrity test.
▶ Check for water in the sump and check the siphon operation.
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