BoilerFaultCodesThe 6 most common faults
01
F37 High DIY-safe
Your boiler has stopped working because the water pressure inside the system has dropped too low.
What to try first
Locate the filling loop underneath your boiler or check your user manual for the pressurising valves.Open the valves slowly to let mains water into the system while watching the pressure gauge.Stop filling once the needle reaches between 1.0 and 1.5 bar on the gauge, then firmly close the valves.
02
A01 High Engineer
Your boiler is trying to start up, but it is failing to light the flame safely.
Full guide for A0103
A05 High Engineer
Your boiler has stopped working because the internal fan that pushes out harmful gases is not operating correctly.
Full guide for A0504
A06 High Engineer
Your boiler is trying to start up and light a flame, but it keeps failing after several attempts and has safely shut itself down.
Full guide for A0605
F10 High Engineer
Your boiler is temporarily unable to accurately measure the temperature of the water flowing through the system due to a faulty sensor.
Full guide for F1006
F13 High Engineer
Your boiler has detected a problem with the temperature sensor attached to the main heat exchanger, which usually stops it from working safely.
Full guide for F13on the Euroterm E27 Plus
Pressure relief valveExpansion vesselPressure sensorIgnition electrodeGas valvePCB
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Euroterm shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue
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