E22 Boiler Fault Code: What It Means on Every Brand

The E22 fault code appears on 4 boiler brands — Andrews, Biasi, Ravenheat and Warmflow — and on all of them it points to the same kind of problem. The details still differ by brand (thresholds, sub-codes, reset procedure), so use the table below to jump to the page for your boiler.

Lockout — engineer likely 4 brands use this code

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 E22 means	Severity	DIY?
AAndrews	The E22 code on an Andrews water heater most likely indicates an ignition or flame detection fault — part of the E2x family of error codes used across the Andrews range (ClassicFlo, HiFlo… Full guide →	Lockout — engineer likely	No
BBiasi	E22 is a safety lockout triggered when the Biasi control board detects a flame signal still present after it has sent the command to close the gas valve (known as the EVG — electronically… Full guide →	Lockout — engineer likely	No
RRavenheat	The E22 code (sometimes displayed alongside E23 on certain Ravenheat models) indicates that the boiler's control board has detected a problem with the flue sensor — either the flue is… Full guide →	Lockout — engineer likely	No
WWarmflow	The E22 code on a Warmflow boiler carries two distinct meanings depending on which model you own. Full guide →	Lockout — engineer likely	No

E22 brand by brand

Andrews E22

The E22 code on an Andrews water heater most likely indicates an ignition or flame detection fault — part of the E2x family of error codes used across the Andrews range (ClassicFlo, HiFlo EVO, EcoFlo, FastFlo and similar models). When the appliance attempts to light, the integrated Honeywell control board either fails to confirm that a flame has been established, or detects a problem with the flame-sensing signal. After a set number of failed ignition attempts, the unit enters a safe lockout and holds the code on the display. Because Andrews does not publish full fault-code lists publicly, always cross-reference with your model's installation manual or Andrews technical support if the description below does not match your symptoms exactly.

Causes, fixes & costs for Andrews E22 → · All Andrews codes

Biasi E22

E22 is a safety lockout triggered when the Biasi control board detects a flame signal still present after it has sent the command to close the gas valve (known as the EVG — electronically controlled gas valve group). In normal operation, once the boiler shuts down, the flame should extinguish immediately as the valve closes. If the control board continues to see a flame signal beyond that point, it treats this as a potentially dangerous condition and locks the boiler out to prevent uncontrolled burning. E22 sits in a family of related EVG lockout codes (E20, E21, E22, E23), each of which requires a manual reset and points to a fault within the gas valve control circuit. A single successful reset may clear it if the fault was a brief glitch, but if the code returns, a Gas Safe registered engineer must investigate before the boiler is used again.

Causes, fixes & costs for Biasi E22 → · All Biasi codes

Ravenheat E22

The E22 code (sometimes displayed alongside E23 on certain Ravenheat models) indicates that the boiler's control board has detected a problem with the flue sensor — either the flue is reaching temperatures above the safe operating limit, or the sensor itself has stopped providing a reliable signal. As a safety precaution, the boiler will lock out to prevent potential damage or danger. The flue sensor is an NTC thermistor: a component whose electrical resistance changes with temperature. It plays a critical role in protecting the plastic elements of the flue system by allowing the boiler to reduce its output or shut down when flue temperatures climb too high. Because Ravenheat produces several boiler ranges, the exact display format of this code can vary slightly by model — always cross-reference with your specific boiler's documentation if you are unsure.

Causes, fixes & costs for Ravenheat E22 → · All Ravenheat codes

Warmflow E22

The E22 code on a Warmflow boiler carries two distinct meanings depending on which model you own. On GS-Series gas boilers (such as the GS25A), E22 signals a parameter or fan-related fault — the boiler's control system has detected a problem with the fan circuit, causing the appliance to shut down as a safety precaution. Without a working fan, combustion gases cannot be safely expelled through the flue, so the boiler locks out to protect occupants. On the Agentis combination boiler range, E22 specifically indicates 'Flash Data Corrupted', meaning the PCB's onboard memory has encountered a storage or data integrity problem. In both cases the boiler will stop operating until the underlying fault is resolved. Always check your model's manual to confirm which interpretation applies to your specific appliance.

Causes, fixes & costs for Warmflow E22 → · All Warmflow codes

Frequently asked questions

Is the E22 fault code the same on every boiler?

Broadly, yes — on Andrews, Biasi, Ravenheat and Warmflow the E22 code points to the same class of fault, and the recommended response is similar. Model-specific details such as sub-codes and reset procedures still vary, so follow the page for your own brand.

Can I fix a E22 fault myself?

Not usually. On every brand listed, E22 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 E22 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.