
Mistral Boiler Error Codes 2021
Initial user checks
You are able to make some checks before calling out a service engineer.
- Check you have enough fuel: check the sight gauge.
- Check the fuel supply valves are open.
- Check the external fire valve hasn’t tripped: press the trip button.
- Is the boiler electrical supply on?
- Is the control panel high limit thermostat tripped? Check and reset if needed.
- Burner control box locked out: check and press the lens.
Mistral Boiler Error Codes
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 |