Worcester Greenstar 24i LPG Boiler Fault Codes

 Blue Light

Indication

Lockout Reset

Button

Off

Off

Permanent mains supply to boiler.

Boiler mains switch.

Fuse F1, 2.5A or Fuse F3, 0.5A

Transformer (both coils below 100Ω).

Otherwise replace control board.

On

Off

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 roomstat/timer). Facia 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 not a permanent live at ST10-LR from another source.

See Flow Sensor Test below. or Diverter valve. Control board.

Fan. Control board.

Slow flash (normally off, flashes on)

Flashing (reset required)

Gas present and at correct pressure.

Combustion CO2 level.

Flue condition.

Ignition electrodes / harness / connections.

Gas valve (coils 140-190Ω) / low voltage harness connection.

Otherwise replace control board.

Slow flash (normally on, flashes off)

Flashing (reset required)

Flue overheat

Heat exchanger overheat

Flue blockage

Heat exchanger blocked. Heat exchanger baffles removed and not refitted.

Water pressure. All air vented. Pump / harness / connections. Water leaks / blockages. Safety thermostats / low voltage wiring harness / connections. Otherwise replace control board.

Blockage in flue system.

Fast flash

Off

Fast flash

Flashing

2 pulses

No light

5 pulses

No light