| Fault | Possible Cause |
|---|---|
| Burner does not start | Air locks, supply lines blocked or tank vent blocked (no fuel getting into tank) |
| Restriction suspected / fuel supply fault | Power supply to the boiler failed, burner control box locked out, burner motor fault or pump seized |
| Burner fault locks out after 15 seconds | Photocell fault, restricted oil supply, combustion setting out of specification |
| No flame established (burner fault) | Ignition failure, oil restricted or nozzle locked |
| Burner fault runs but continually pulsates | Condensate trap blocked or flue system blocked |
| Lock-out | Losing oil in the supply suction line or oil level in tank below minimum level |
| Burner running but smokes | Tank topped with wrong fuel/ Air supply restricted/ Dust build up |
| Burner flame shuts down slowly | Balanced flue system leaking/ Combustion leaks/ Suction line drawing air into fuel |
| Burner fails to reach working temperature | Burner output restricted/ Low efficiency/ Control thermostat fault |
| Oil smells | Oil leakage at connection |
| No hot water | Circulating pump seized/ Programmer channel off |
| Flow and water temperature low | Programmer for central heating or domestic hot water are off, debris build-up or low water supply pressure |
| No central heating or hot water | Programmer channels are off, thermostat fault or turned off |
| Thermostat trips off | Fault circulating pump |
| No central heating | Spring fault or return valve not moving or operating properly – room stat error |
| No domestic hot water | Spring fault, jammed in how water mode, flow switch blocked or faulty |
| Discharges on pressure relief valve | Pressure vessel has lost charge, insufficient expansion volume |