Common problems guide

The most common Euroterm boiler problems

The faults we see most often across the Euroterm range — with plain-English causes, what to check first, estimated repair costs, and whether it's a DIY job or needs a Gas Safe engineer. Based on fault-code data across 1 Euroterm boiler models.

18 unique codes
1 models covered
3 DIY-safe (top 8)
8 engineer needed

The most common Euroterm faults

01
A03 High DIY-safe

Your boiler has become too hot and has shut itself down as a safety precaution to prevent internal damage.

What to try first

Wait for the boiler to cool down for at least 30 minutesCheck that all radiator valves are fully openCheck the boiler pressure gauge and top up to 1.5 bar if it is lowPress the Reset button on the control panel

Est. cost
£120-300
Parts
Circulation Pump, Overheat Thermostat, Main Heat Exchanger (Descaling)
Full guide for E27 Plus A03
02
A06 High DIY-safe

Your boiler is trying to start up but cannot successfully light the gas to produce a flame.

What to try first

Check that your gas supply is turned on at the meterIf you have a prepayment meter, ensure you have credit availableCheck if other gas appliances, like a cooker, are working correctlyReset the boiler by following the instructions in your user manual

Est. cost
£120-350
Parts
Ignition electrode, Flame sensing probe, Gas valve
Full guide for E27 Plus A06
03
F37 High DIY-safe

Your boiler has switched itself off because the water pressure in the system is too low for it to operate safely.

What to try first

Locate the filling loop (usually a silver flexible hose) underneath the boiler.Open the one or two taps on the loop slowly until you hear water moving.Watch the pressure gauge until it reaches between 1.0 and 1.5 bar, then close the taps tightly.

Est. cost
£0-120
Parts
Filling loop, Pressure sensor, Pressure gauge
Full guide for E27 Plus F37
04
A02 High Engineer

Your boiler is detecting a flame even though the burner should be switched off, which is a safety conflict causing the system to lock out.

Est. cost
£120-280
Parts
Ionisation electrode, Gas valve, Printed Circuit Board (PCB)
Full guide for E27 Plus A02
05
F07 High Engineer

Your boiler has shut down because the exhaust gases have become too hot, which is usually caused by a blockage or a build-up of debris inside the system.

Est. cost
£150-£450
Parts
Main Heat Exchanger, Flue NTC Sensor, Burner
Full guide for E27 Plus F07
06
F10 High Engineer

Your boiler's internal thermometer that measures outgoing water temperature has developed a fault, meaning the system cannot safely monitor heat levels.

Est. cost
£90-160
Parts
NTC Temperature Sensor, Sensor Wiring Harness
Full guide for E27 Plus F10
07
F12 High Engineer

Your boiler has detected an issue with a temperature sensor that monitors the water being sent to your taps or radiators, meaning it cannot heat water accurately.

Est. cost
£90-160
Parts
NTC Temperature Sensor, Wiring Harness, Main Control Board
Full guide for E27 Plus F12
08
F13 High Engineer

Your boiler's temperature sensor responsible for monitoring the heat exchanger has stopped working correctly, causing the system to shut down for safety.

Est. cost
£90-160
Parts
NTC Temperature Sensor, Exchanger Probe, Wiring Harness
Full guide for E27 Plus F13

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