E47 Boiler Fault Code: What It Means on Every Brand

The E47 fault code appears on 2 brands — Alpha and Andrews — and it does not mean the same thing on each. The same two or three characters can signal a pressure problem on one boiler and an ignition fault on another, so identify your brand first and use the table below to jump to the right page.

Up to: Lockout — engineer likely 2 brands use this code Meaning differs by brand

Which brand is your boiler?

The brand is printed on the front casing. Tap your brand for the full causes, fixes and repair costs.

Brand	What E47 means	Severity	DIY?
AAlpha	The E47 code on an Alpha boiler indicates that the boiler has detected abnormally high flue gas temperatures and has responded by throttling its own burner output as a protective measure. Full guide →	Engineer may be needed	No
AAndrews	The E47 fault code on Andrews boilers indicates that the boiler's primary temperature sensor (sensor 1) has reported a reading that falls outside the acceptable operating range — either… Full guide →	Lockout — engineer likely	No

E47 brand by brand

Alpha E47

The E47 code on an Alpha boiler indicates that the boiler has detected abnormally high flue gas temperatures and has responded by throttling its own burner output as a protective measure. Rather than locking out completely, the boiler enters a reduced-power mode to prevent overheating in the exhaust path. In practice this usually points to something restricting either the flow of water around the system or the escape of combustion gases through the flue — both of which cause heat to build up where it shouldn't. The boiler is telling you that something needs attention before it can run safely at full output again.

Causes, fixes & costs for Alpha E47 → · All Alpha codes

Andrews E47

The E47 fault code on Andrews boilers indicates that the boiler's primary temperature sensor (sensor 1) has reported a reading that falls outside the acceptable operating range — either unexpectedly low or dangerously high. The boiler's safety system interprets this as a potential risk and locks out, requiring a manual reset once the underlying problem has been identified and resolved. The sensor in question is typically an NTC thermistor, a small component that tracks water temperature by varying its electrical resistance. When the control board (PCB) receives a signal it cannot trust — whether due to a failed sensor, a wiring fault, or a genuine overheating event — it triggers the E47 lockout to protect the boiler and your home.

Causes, fixes & costs for Andrews E47 → · All Andrews codes

Frequently asked questions

Is the E47 fault code the same on every boiler?

No. E47 means different things on different brands — see the table above. Always identify your boiler's brand (it is printed on the front casing) before acting on any advice about the code.

Can I fix a E47 fault myself?

Not usually. On every brand listed, E47 points to a fault that needs a suitably registered engineer to diagnose and repair. A single reset to rule out a transient glitch is reasonable; repeated resets are not.

Who should I call about a E47 fault?

For gas boilers, a Gas Safe registered engineer — it is a legal requirement for any work on the appliance. If you smell gas at any point, leave the property and call the National Gas Emergency line on 0800 111 999.

General guidance only — not a substitute for professional advice, and not certified by a registered engineer. Any work on a gas appliance must be carried out by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.