E384 Boiler Fault Code: What It Means on Every Brand

The E384 fault code appears on 3 brands — Baxi, Main and Potterton — and it does not mean the same thing on each. The same two or three characters can signal a pressure problem on one boiler and an ignition fault on another, so identify your brand first and use the table below to jump to the right page.

Up to: Stop & check now 3 brands use this code Meaning differs by brand

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 E384 means	Severity	DIY?
BBaxi	The E384 code appears when a Baxi boiler detects what it believes to be an active flame even though the gas valve has been commanded off. Full guide →	Lockout — engineer likely	No
MMain	The E384 fault code indicates that the boiler's PCB (printed circuit board) has detected a 'false flame' signal — meaning it believes a flame is present when the gas valve should be fully… Full guide →	Stop & check now	No
PPotterton	The E384 fault code appears on Potterton boilers when the PCB detects a flame signal at a point when the gas valve should be closed and no flame should be present. Full guide →	Lockout — engineer likely	No

E384 brand by brand

Baxi E384

The E384 code appears when a Baxi boiler detects what it believes to be an active flame even though the gas valve has been commanded off. Because the boiler's control system expects no flame signal at that moment, it treats the reading as a potentially dangerous anomaly and locks the boiler out as a precaution. The boiler will not restart until the fault is cleared and, where necessary, the underlying component is repaired or replaced. This is a safety lockout — do not attempt to bypass it or keep resetting the boiler repeatedly.

Causes, fixes & costs for Baxi E384 → · All Baxi codes

Main E384

The E384 fault code indicates that the boiler's PCB (printed circuit board) has detected a 'false flame' signal — meaning it believes a flame is present when the gas valve should be fully closed, or it is receiving an unexpected flame signal that doesn't match the boiler's normal operating sequence. Because this relates directly to gas control and combustion safety, the boiler will lock out to prevent any potentially dangerous situation from developing. If your boiler is displaying E384 but has not locked out, switch it off immediately and call a Gas Safe registered engineer. This fault code is shared across Main, Baxi, and Potterton boilers, as all three brands sit under the same parent company (BDR Thermea Group) and use an identical PCB and fault-code platform — so the causes and fixes described here apply equally to all three ranges.

Causes, fixes & costs for Main E384 → · All Main codes

Potterton E384

The E384 fault code appears on Potterton boilers when the PCB detects a flame signal at a point when the gas valve should be closed and no flame should be present. In other words, the boiler's control board is registering combustion activity that it doesn't expect — a so-called 'false flame' signal. Because this involves the gas circuit behaving unpredictably, the boiler will lock out as a safety precaution. This fault must be treated seriously: if your boiler has not locked itself out automatically, switch it off at the isolator and contact a Gas Safe registered engineer without delay. Do not attempt repeated resets — this will not resolve the underlying issue and could be unsafe.

Causes, fixes & costs for Potterton E384 → · All Potterton codes

Frequently asked questions

Is the E384 fault code the same on every boiler?

No. E384 means different things on different brands — see the table above. Always identify your boiler's brand (it is printed on the front casing) before acting on any advice about the code.

Can I fix a E384 fault myself?

Not usually. On every brand listed, E384 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 E384 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.