E46 Boiler Fault Code: What It Means on Every Brand

The E46 fault code appears on 3 brands — Alpha, Ravenheat and Warmflow — 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 3 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 E46 means	Severity	DIY?
AAlpha	E46 does not appear in any publicly documented fault code list for Alpha boilers — including the E-Tec, E-Tec Plus, Evoke, InTec, CD, and Protec Plus ranges. Full guide →	Engineer may be needed	No
RRavenheat	The E46 code on a Ravenheat boiler signals that the PCB is receiving an incorrect, absent, or out-of-range signal from the water pressure sensor. Full guide →	Lockout — engineer likely	No
WWarmflow	The E46 code appears on Warmflow boilers — including the Agentis series — when the control board detects a problem with the system pressure sensor. Full guide →	Lockout — engineer likely	No

E46 brand by brand

Alpha E46

E46 does not appear in any publicly documented fault code list for Alpha boilers — including the E-Tec, E-Tec Plus, Evoke, InTec, CD, and Protec Plus ranges. This means the code could be model-specific or firmware-specific, or the display may be showing a similar-looking code that has been misread. Before taking any action, it is worth double-checking the display carefully — Alpha boiler screens can make codes like E43, E40, E16, or E60 look similar to E46 at a glance. If the display definitely shows E46, consult your boiler's installation manual or contact Alpha Innovation directly, as they will have model-level fault data not available in public sources. If no manual is to hand, a Gas Safe registered engineer is the safest next step.

Causes, fixes & costs for Alpha E46 → · All Alpha codes

Ravenheat E46

The E46 code on a Ravenheat boiler signals that the PCB is receiving an incorrect, absent, or out-of-range signal from the water pressure sensor. This could be caused by a sensor that has drifted out of calibration, a wiring fault creating an open or short circuit, or a blocked sensor port. Because the boiler cannot confirm safe operating pressure, it locks out as a precaution. Note that Ravenheat Manufacturing Limited was dissolved in 2025, meaning parts are increasingly scarce — factor this into any repair decision, particularly on older units.

Causes, fixes & costs for Ravenheat E46 → · All Ravenheat codes

Warmflow E46

The E46 code appears on Warmflow boilers — including the Agentis series — when the control board detects a problem with the system pressure sensor. This could mean the sensor has lost its electrical connection, is producing readings outside the expected range, or has failed outright. As a safety measure, the boiler locks out rather than continuing to operate without reliable pressure data. The fault typically displays in red on the boiler's screen to indicate a lockout condition rather than a simple warning.

Causes, fixes & costs for Warmflow E46 → · All Warmflow codes

Frequently asked questions

Is the E46 fault code the same on every boiler?

No. E46 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 E46 fault myself?

Not usually. On every brand listed, E46 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 E46 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.