BoilerFaultCodes A01 Your boiler is trying to start up, but it is failing to light the flame safely.
Your boiler is trying to start up, but it is failing to light the flame safely.
Parts commonly replaced
- Ignition electrode
- Gas valve
- PCB
Euroterm E27 Plus Fault codes & diagnostics
27 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 27 kW 2017 onwards
GC Number 47-267-66
Download the Euroterm E27 Plus manual
PDF
Versions & GC numbers
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Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 4 Emergency
17 High
3 Medium
3 Low
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 47-267-66 | E27 PLUS | 2017–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Euroterm E27 Plus faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 27 documented codes
Tap any card for details
A02 Your boiler is picking up a signal that a flame is present even when the heating is switched off, which is a safety precaution that causes a lockout.
Your boiler is picking up a signal that a flame is present even when the heating is switched off, which is a safety precaution that causes a lockout.
Parts commonly replaced
- Gas valve
- Printed Circuit Board (PCB)
- Flame electrode
Related codes
A03 Your boiler has automatically shut down because the internal water temperature reached an unsafely high level.
Your boiler has automatically shut down because the internal water temperature reached an unsafely high level.
Parts commonly replaced
- High limit thermostat
- PUMP
- PCB
Related codes
A04 Your boiler has detected an issue with the exhaust gases leaving the flue, so it has safely shut down to prevent any harmful emissions in your home.
Your boiler has detected an issue with the exhaust gases leaving the flue, so it has safely shut down to prevent any harmful emissions in your home.
Parts commonly replaced
- Flue sensor
- Air pressure switch
- Fan
Related codes
A05 Your boiler has stopped working because the internal fan that pushes out harmful gases is not operating correctly.
Your boiler has stopped working because the internal fan that pushes out harmful gases is not operating correctly.
Parts commonly replaced
- Flue gas fan
- Air pressure switch
- Printed circuit board (PCB)
Related codes
A06 Your boiler is trying to start up and light a flame, but it keeps failing after several attempts and has safely shut itself down.
Your boiler is trying to start up and light a flame, but it keeps failing after several attempts and has safely shut itself down.
Parts commonly replaced
- Ignition electrode
- Gas valve
- PCB
Related codes
A41 Your boiler has detected that one of its temperature sensors is not attached correctly or is failing to read the water temperature properly.
Your boiler has detected that one of its temperature sensors is not attached correctly or is failing to read the water temperature properly.
Parts commonly replaced
- NTC temperature sensor
- Sensor retaining clip
Related codes
A42 Your boiler is temporarily locked out because it cannot accurately read the temperature of the water flowing through the system.
Your boiler is temporarily locked out because it cannot accurately read the temperature of the water flowing through the system.
Parts commonly replaced
- Flow temperature sensor
- NTC thermistor
- Wiring harness
Related codes
A44 Your boiler has detected that one of its temperature sensors is not positioned correctly or has come loose, temporarily stopping the system for safety.
Your boiler has detected that one of its temperature sensors is not positioned correctly or has come loose, temporarily stopping the system for safety.
Parts commonly replaced
- Temperature sensor
- Sensor retaining clip
Related codes
A61 Your boiler has detected an internal communication error with its main control unit, causing it to shut down safely.
Your boiler has detected an internal communication error with its main control unit, causing it to shut down safely.
Parts commonly replaced
- PCB
- Wiring harness
Related codes
Showing 11–20 of 27
A62 Your boiler has temporarily stopped working because the main computer cannot talk to the part that controls the gas supply.
Your boiler has temporarily stopped working because the main computer cannot talk to the part that controls the gas supply.
Parts commonly replaced
- Gas valve
- Wiring harness
- Printed Circuit Board (PCB)
Related codes
A63 Your boiler has detected an internal communication failure with its main electronic control unit, meaning it has temporarily stopped working to keep you safe.
Your boiler has detected an internal communication failure with its main electronic control unit, meaning it has temporarily stopped working to keep you safe.
Parts commonly replaced
- Main PCB
- Wiring harness
Related codes
A64 Your boiler has detected an internal communication problem with its main control unit, causing it to lock out for safety.
Your boiler has detected an internal communication problem with its main control unit, causing it to lock out for safety.
Parts commonly replaced
- PCB
- Wiring harness
Related codes
F07 Your boiler has detected that the exhaust gases leaving the system are dangerously hot, so it has safely shut down to prevent damage or overheating.
Your boiler has detected that the exhaust gases leaving the system are dangerously hot, so it has safely shut down to prevent damage or overheating.
Parts commonly replaced
- Flue gas sensor
- Heat exchanger
- Main PCB
Related codes
F10 Your boiler is temporarily unable to accurately measure the temperature of the water flowing through the system due to a faulty sensor.
Your boiler is temporarily unable to accurately measure the temperature of the water flowing through the system due to a faulty sensor.
Parts commonly replaced
- Flow NTC thermistor
- Flow sensor wiring harness
Related codes
F11 Your boiler has temporarily stopped working because it cannot properly read the temperature of the water returning from your radiators.
Your boiler has temporarily stopped working because it cannot properly read the temperature of the water returning from your radiators.
Parts commonly replaced
- Return temperature sensor
- Wiring harness
Related codes
F12 Your boiler is struggling to detect the temperature of your hot water properly, which usually means it will temporarily stop providing hot water to your taps.
Your boiler is struggling to detect the temperature of your hot water properly, which usually means it will temporarily stop providing hot water to your taps.
Parts commonly replaced
- Domestic Hot Water NTC Sensor
- Wiring harness
Related codes
F13 Your boiler has detected a problem with the temperature sensor attached to the main heat exchanger, which usually stops it from working safely.
Your boiler has detected a problem with the temperature sensor attached to the main heat exchanger, which usually stops it from working safely.
Parts commonly replaced
- NTC thermistor / exchanger probe
- Wiring harness
Related codes
F14 Your boiler has temporarily stopped working because it is having trouble measuring the temperature of the water flowing through the system.
Your boiler has temporarily stopped working because it is having trouble measuring the temperature of the water flowing through the system.
Parts commonly replaced
- Flow thermistor
- NTC sensor
- Wiring harness
Related codes
F15 Your boiler has detected an issue with the internal fan, which safely removes harmful exhaust gases from your home, so it has shut down to protect you.
Your boiler has detected an issue with the internal fan, which safely removes harmful exhaust gases from your home, so it has shut down to protect you.
Parts commonly replaced
- Flue gas fan
- Air pressure switch
- Printed circuit board (PCB)
Related codes
Showing 21–27 of 27
F34 Your boiler has detected that the electricity supply coming into your home has dropped too low to run safely.
Your boiler has detected that the electricity supply coming into your home has dropped too low to run safely.
Parts commonly replaced
- Main PCB
- Power Supply Unit
Related codes
F35 Your boiler has detected an unstable electrical supply coming from your home's mains power, causing it to temporarily pause operation to protect its internal electronics.
Your boiler has detected an unstable electrical supply coming from your home's mains power, causing it to temporarily pause operation to protect its internal electronics.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Power Supply Unit
Related codes
F37 Your boiler has stopped working because the water pressure inside the system has dropped too low.
Your boiler has stopped working because the water pressure inside the system has dropped too low.
What to check 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.
Parts commonly replaced
- Pressure relief valve
- Expansion vessel
- Pressure sensor
Related codes
F39 Your boiler is not receiving the correct temperature reading from the outdoor weather sensor, but your heating and hot water should still work normally.
Your boiler is not receiving the correct temperature reading from the outdoor weather sensor, but your heating and hot water should still work normally.
Parts commonly replaced
- External temperature sensor
- Wiring connection
Related codes
F43 Your boiler has temporarily shut down to prevent the main heat exchanger from overheating.
Your boiler has temporarily shut down to prevent the main heat exchanger from overheating.
Parts commonly replaced
- NTC thermistor
- Heat exchanger
- Circulating pump
Related codes
F52 Your boiler is temporarily unable to accurately measure the temperature of the water flowing through the system due to a sensor issue, which will usually stop your heating and hot water from working safely.
Your boiler is temporarily unable to accurately measure the temperature of the water flowing through the system due to a sensor issue, which will usually stop your heating and hot water from working safely.
Parts commonly replaced
- Flow temperature sensor
- Wiring harness
Related codes
F66 Your boiler has detected an internal communication fault with its main electronic brain, which safely shuts down the system to prevent unpredictable operation.
Your boiler has detected an internal communication fault with its main electronic brain, which safely shuts down the system to prevent unpredictable operation.
Parts commonly replaced
- Main Control Board
- Wiring Harness
Related codes
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