Worcester Greenstar 2000 Installation And Maintenance Instructions Manual page 80

Fault finding and diagnosis
Description
2911 V Calibration failed
2912 V No flame signal during calibration
2913 – Flame signal too low during calibration
2914 – There is no communication between the
appliance controller and burner module
2915 V The fan keeps running after the post purge ▶ Reset the appliance.
2916 V Gas valve was detected to be open during
post purge
2917 V No flame signal when checking the
combustion control
2918 – Fault in combustion control
2920 V Fault in flame monitoring
2921 – Boiler electr. in test mode
2922 – Internal fault
2923 V Unexpected feedback from the modulating/
current controlled gas valve
2924 V No feedback from the gas valve
2925 V Too low feedback from the modulating gas
valve
2926 V Too high feedback from the modulating/
current controlled gas valve
80
Remedy
Tip: Check the ceramic insulator is not damaged, this can cause the spark to earth, twist
and pull the ceramic insulator to ensure it is not broken.
▶ Check the flame sense and the lead and replace if required.
▶ Check the earth tags on the boiler and on the electrodes.
▶ Check the operation of the siphon and no water collecting in the sump.
▶ Replace the air and/or gas ratio control valve.
▶ Replace the control unit and/or burner control unit.
Tip: Check the ceramic insulator is not damaged, this can cause the spark to earth, twist
and pull the ceramic insulator to ensure it is not broken.
▶ Check the flame sense and the lead and replace if required.
▶ Check the earth tags on the boiler and on the electrodes.
▶ Check the operation of the siphon and no water collecting in the sump.
▶ Replace the air and/or gas ratio control valve.
▶ Replace the control unit and/or burner control unit.
▶ Check and replace flame sense electrodes (and interconnecting leads).
▶ Restart the appliance to see if the problem re-occurs.
▶ If the fault remains after resetting: the burner controller (PCB) is defective.
▶ Create a heat demand; check if the boiler fires up.
▶ Check the voltage to the fan and the continuity of the fan harness.
▶ Check the power modulation on the fan.
▶ PCB may be defective.
▶ Carry out a localised tightness test on the gas valve and replace if required.
▶ Check the voltage to gas valve.
▶ The gas valve or the PCB may have a fault.
▶ Disconnect power and then reconnect.
▶ Trigger heat demand.
▶ Wait 5 minutes.
▶ If the fault re-occurs within that time, reset the appliance without disconnecting the
supply voltage.
This triggers a calibration of the ionisation circuits.
▶ If the fault is still present after the calibration, the control unit is faulty and must be
replaced.
▶ Clean the siphon and drain water out of the appliance (gas side).
Possible PCB fault, no checks available.
▶ Check and replace control unit.
Possible PCB fault, no checks available.
▶ Check the voltage to the gas valve.
▶ Check the resistance of the gas valve coils.
▶ Check the continuity of harness and replace if required.
▶ The gas valve or the PCB may have a fault.
▶ Check the voltage to the gas valve.
▶ Check the resistance of the gas valve coils.
▶ Check the continuity of harness and replace if required.
▶ Check the voltage to the gas valve.
▶ Check the resistance of the gas valve coils.
▶ Check the continuity of harness and replace if required.
▶ The gas valve or the PCB may have a fault.
Greenstar 2000 – 6 721 820 552 (2021/02)