Worcester Greenstar 24i System LPG Boiler Fault Codes

Lockout reset

button

Boiler not operating during central heating demand (HW ok)

Boiler operating without live demand at ST10-LR (from external roomstat timer).

Boiler not operating during hot water demand (CH ok).

Boiler not operating during any demand.

Live demand at ST10-LR (from external room thermostat/timer) Fascia mounted timer (if fitted) CH knob in winter position Diverter valve Control board

Some older thermostats (containing capacitors) may give a low voltage return at ST10-LR when the thermostat contacts are open. Check that there is no permanent live at ST10-LR from another source.

Ensure cold inlet DHW outlet are correctly piped i.e. are not crossed piped. Flow Turbine test:

Check for 5 volts d.c. across red and black wires

Check for 2.5 volts d.c. across the yellow and red wires with the water flowing. Check diverter and motor and control board.

Fan. Control board

Gas present and at correct pressure?

Gas valve

– Check that there is 35V d.c. to each solenoid

– Check the resistance of each solenoid: Top solenoid = 380 Ω ± 10% (342 - 418 Ω) Bottom solenoid = 190 Ω ± 10% (171 - 209 Ω)

Combustion CO2 level.

Flue condition.

– Blocked flue? 

Blocked condensate pipe or frozen condensate. 

Gas valve adjustment.

Ignition electrodes/harness/connections. – Check for condition and continuity

Otherwise replace control board

Flue overheat

Heat exchanger overheat

Heat exchanger baffles removed and not refitted.

Heat exchanger blocked

Water pressure

All air vented

Pump/harness/connections.

Water leaks/blockage

Safety thermostats/low voltage wiring harness/connections

Otherwise replace control board

Temperature sensors

– Check condition and continuity of leads/sensors

Fan

– 230V a.c. across the live (purple) and neutral (brown)

Fan lead

– Check continuity

Code plug

– Is code plug missing or not inserted properly.