It appears that your cart is currently empty
Blue Light Indication |
Lockout reset button |
Fault | Possible solution/check |
Off | Off | No power at control board | Permanent mains supply to boiler. Fuse F1 - 2.5A or Fuse F3 - 0.5A. Transformer (primary coil below 60 Ω, both secondary coil below 10 Ω). 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 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 |
Slow flash (normally off, flashes on) | Flashing (reset required) | Ignition lockout |
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 |
Slow flash (normally on, flashes off) | Flashing (reset required) |
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 |
Fast flash | Off | Volatile lockout - fan does not run |
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. |
Fast flash | Flashing | Internal fault | Replace control board |
2 pulses | No light | Not a fault code | Service mode selected to min, press service button to return to normal. |
5 pulses | No light | Not a fault code | Service mode selected to max, press service button to return to normal. |