E193 Boiler Fault Code: What It Means on Every Brand

The E193 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 E193 means	Severity	DIY?
BBaxi	The E193 code appears on Baxi boilers when the pre-circulation check fails at start-up. Full guide →	Lockout — engineer likely	No
PPotterton	The E193 code on a Potterton boiler signals a circulation problem — the boiler has detected that hot water is not moving around the heating system as it should. Full guide →	Lockout — engineer likely	No

E193 brand by brand

Baxi E193

The E193 code appears on Baxi boilers when the pre-circulation check fails at start-up. Before the burner fires, the boiler briefly runs its circulation pump to confirm water is moving freely around the system. If the PCB detects that flow or temperature gradient conditions aren't met during this short test — most likely because the pump isn't shifting water properly — it triggers the E193 lockout. Because Baxi uses 'E' prefix codes to denote hard lockouts, the boiler will not attempt to restart on its own; the fault must be properly investigated and cleared before heating or hot water will resume. A related code, E125, covers primary circulation faults more broadly, while E193 specifically targets the pre-circulation phase at ignition.

Causes, fixes & costs for Baxi E193 → · All Baxi codes

Potterton E193

The E193 code on a Potterton boiler signals a circulation problem — the boiler has detected that hot water is not moving around the heating system as it should. This is most commonly linked to a pump or flow fault, where the boiler senses a cold return pipe or inadequate water movement. On some Potterton models the code can also point to a communication breakdown between the control board and the room thermostat, though the circulation interpretation is the more widely reported cause. Either way, the boiler will typically lock out to protect itself, and you may notice cold radiators, gurgling noises from the pipework, or unusual sounds from the pump area.

Causes, fixes & costs for Potterton E193 → · All Potterton codes

Frequently asked questions

Is the E193 fault code the same on every boiler?

Broadly, yes — on Baxi and Potterton the E193 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 E193 fault myself?

Not usually. On every brand listed, E193 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 E193 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.