E131 Boiler Fault Code: What It Means on Every Brand

The E131 fault code appears on 2 boiler brands — Baxi and Potterton — 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 E131 means	Severity	DIY?
BBaxi	The E131 code means your Baxi boiler has detected that the flue gas temperature has climbed above its safe operating limit — specifically, the flue gas exceeding 85°C or the flow… Full guide →	Lockout — engineer likely	Some checks
PPotterton	The E131 fault code on a Potterton boiler signals a flue overheat lockout. Full guide →	Lockout — engineer likely	No

E131 brand by brand

Baxi E131

The E131 code means your Baxi boiler has detected that the flue gas temperature has climbed above its safe operating limit — specifically, the flue gas exceeding 85°C or the flow temperature sensor reading above 90°C will trigger this shutdown. The boiler locks out completely as a built-in safety measure to prevent damage and protect your home. It will not fire again until the fault has been acknowledged and, where necessary, resolved. Do not attempt to defeat or bypass the safety lockout — it exists for good reason.

Causes, fixes & costs for Baxi E131 → · All Baxi codes

Potterton E131

The E131 fault code on a Potterton boiler signals a flue overheat lockout. In plain terms, the boiler has detected that flue gas temperatures have climbed beyond the safe threshold — typically around 85°C — and has shut itself down as a protective measure to prevent damage or danger. Once tripped, the boiler will not restart until the underlying cause has been addressed. It is worth noting that on some Potterton models, particularly the Promax Combi 28 HE, E131 can instead point to a flame detection fault linked to ignition components or the PCB rather than a straightforward flue overheat. Because the fault's precise meaning can vary across the Promax, Assure, and Gold/Titanium ranges, it is always worth cross-referencing your specific model's manual or speaking to a Gas Safe engineer if you are unsure which interpretation applies to your boiler.

Causes, fixes & costs for Potterton E131 → · All Potterton codes

Frequently asked questions

Is the E131 fault code the same on every boiler?

Broadly, yes — on Baxi and Potterton the E131 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 E131 fault myself?

On some brands there are safe homeowner checks first — typically system pressure, the condensate pipe in cold weather, and a single reset. The underlying repair usually needs a registered engineer. Never open the boiler casing yourself.

Who should I call about a E131 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.