E.04-.10 Boiler Fault Code: What It Means on Every Brand

The E.04-.10 fault code appears on 2 boiler brands — Baxi and Remeha — 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 2 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 E.04-.10 means	Severity	DIY?
BBaxi	The Baxi E.04 series flags a permanent safety lockout linked to a problem with the gas valve or gas/air unit. Full guide →	Lockout — engineer likely	No
RRemehashown as E.04.10	The E.04.10 code appears on your Remeha boiler when it has made five consecutive attempts to light the burner and failed every time. Full guide →	Lockout — engineer likely	No

E.04-.10 brand by brand

Baxi E.04-.10

The Baxi E.04 series flags a permanent safety lockout linked to a problem with the gas valve or gas/air unit. The boiler shuts down and will not restart until the underlying fault is resolved. The .10 sub-code narrows the scope further: depending on your Baxi model, it can indicate a faulty external temperature probe, a gas valve wiring or connection issue, low system water pressure, or a central heating NTC sensor fault. Because the boiler has locked out for a safety-related reason, a reset alone will rarely fix it — the root cause must be identified first. Other sub-codes in the E.04 family (e.g. .11 through .17) point to related gas valve or gas/air unit faults and are handled by the same diagnostic process described on this page.

Causes, fixes & costs for Baxi E.04-.10 → · All Baxi codes

Remeha E.04.10

The E.04.10 code appears on your Remeha boiler when it has made five consecutive attempts to light the burner and failed every time. After these repeated unsuccessful starts, the boiler enters a hard lockout — it shuts itself down completely and will not try again until you manually reset it. This safety mechanism prevents unburnt gas from accumulating. The boiler will display E.04.10 and remain off until the root cause is addressed and the unit is reset by hand.

Causes, fixes & costs for Remeha E.04.10 → · All Remeha codes

Frequently asked questions

Is the E.04-.10 fault code the same on every boiler?

Broadly, yes — on Baxi and Remeha the E.04-.10 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 E.04-.10 fault myself?

Not usually. On every brand listed, E.04-.10 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 E.04-.10 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.