E.01-.11 Boiler Fault Code: What It Means on Every Brand

The E.01-.11 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.01-.11 means	Severity	DIY?
BBaxi	The Baxi E.01–.11 fault code tells you that the boiler's control system has detected the combustion fan running at an incorrect speed — either too fast, too slow, or erratically. Full guide →	Lockout — engineer likely	No
RRemehashown as E.01.11	The E.01.11 code on Remeha boilers corresponds to fault E11 in the boiler's diagnostic system. Full guide →	Lockout — engineer likely	No

E.01-.11 brand by brand

Baxi E.01-.11

The Baxi E.01–.11 fault code tells you that the boiler's control system has detected the combustion fan running at an incorrect speed — either too fast, too slow, or erratically. Because the fan is responsible for drawing fresh air into the burner and safely expelling exhaust gases (including carbon monoxide) through the flue, any deviation from the expected speed triggers an immediate safety lockout. The boiler will not fire until the root cause is identified and resolved. The suffix numbers (.01 through .11) reflect the specific point in the startup or run cycle at which the fan speed error was detected, but all variants share the same underlying cause: a fan or airflow problem that must not be ignored.

Causes, fixes & costs for Baxi E.01-.11 → · All Baxi codes

Remeha E.01.11

The E.01.11 code on Remeha boilers corresponds to fault E11 in the boiler's diagnostic system. It indicates that the temperature inside the airbox has risen to an unsafe level while the boiler is firing, triggering a safety lockout to prevent further damage. The root cause is almost always combustion gases or hot air escaping from the heat exchanger and entering the airbox — typically because a seal around the viewing glass or heat exchanger front plate has failed or come loose. In more serious cases, the heat exchanger itself may have cracked or deteriorated structurally. Because this fault involves potential overheating at the heart of the boiler's combustion system, it always requires inspection by a Gas Safe registered engineer before the boiler is put back into service.

Causes, fixes & costs for Remeha E.01.11 → · All Remeha codes

Frequently asked questions

Is the E.01-.11 fault code the same on every boiler?

Broadly, yes — on Baxi and Remeha the E.01-.11 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.01-.11 fault myself?

Not usually. On every brand listed, E.01-.11 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.01-.11 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.