Baxi E384 fault codewhat it means and how to fix it
False flame: the board sees a flame signal when the burner should be off. Baxi's manuals point at the electrode, its lead and the PCB. Resettable, but not a fault to live with.
Take care
Get a Gas Safe registered engineer to look at your Baxi E384
We do not pass enquiries to a repair firm, so there is no form here. Find a Gas Safe registered engineer through the Gas Safe Register, and ask to see their registration card when they arrive — it is the register, not the van, that tells you they are qualified.
What E384 means
E384 is "False flame" in every Baxi digital-display table, and "False flame (parasitic flame)" on Baxi's professional page, where it is paired with the older two-digit rendering 164. The board monitors the flame-sensing electrode continuously, and if it registers a flame current at a moment when no flame should exist — before ignition, or after the valve has closed — it stops and shows E384 rather than open the gas valve onto what it thinks is a fire already burning.
The 600 and 800 manuals list it among the codes that can be relit by "pressing the Reset button for 1 to 3 seconds", and their fault-finding flow says that "if 09, 15, 110 or 384 is flashing or re-occurs regularly, check all PCB connections. If this has no effect replace the PCB."
A flame signal without a flame is nearly always electrical: moisture or deposit on the electrode insulator giving a leakage path to earth, a chafed or damp electrode lead, an earth fault on the appliance, or the board's own flame-detection circuit. It can also be a flame that really is still burning — a gas valve that is not closing fully and leaving a small flame at the burner — which is the one cause that is not electrical and the reason the boiler treats the condition seriously. Baxi print E384 on the digital-display boilers only; the selector-switch generation has no equivalent code.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Electrode insulator tracking | Condensation or combustion deposit on the ceramic gives the sensing current a path to earth. The board reads a small current and calls it a flame. Cleaning or replacing the electrode (Baxi 7686344 on the 600 and 800) is the fix. | Common |
| Electrode lead or connection | A lead resting against the case, a damp connector, or a cracked boot. Baxi's ignition flow checks the electrode connection and lead before the board. | Common |
| PCB flame-detection circuit | Baxi say to check all PCB connections and then replace the PCB if E384 recurs regularly. The detection circuit is on the board and cannot be repaired separately. | Occasional |
| Gas valve not closing fully | A genuine residual flame after the valve should have shut. Rare, but it is the case that justifies the boiler locking out rather than ignoring the signal, and it is a gas valve replacement. | Rare |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£110–£400
Time on site
45 minutes
Electrode (Baxi 7686344) fitted £110–£180. Lead or connector repair within a service call. PCB £250–£400.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Baxi / Potterton / Main detection and spark ignition electrode
7686344£25–£60Authorised Baxi parts distributor
Price checked 28 September 2026
Baxi / Potterton / Main main PCB
£150–£320Authorised Baxi parts distributor
Price checked 28 September 2026
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Related Baxi fault codes
- E133Get it checkedBaxi's ignition lockout: "the gas supply has been interrupted, ignition has failed or the flame has not been detected". Check the gas is on, reset once. If it returns, stop.Related: ignition and gas supply
- E.04.10Get it checkedIgnition failure on the Baxi 200/400 Combi and every Combi 2: the burner would not light after its allowed attempts. Baxi's own quick guide names it the frozen-condensate code you can fix yourself.Related: ignition and gas supply
- E128Get it checkedFlame failure while the burner was running, on the digital-display Baxis. The boiler relights itself unless it keeps happening; Baxi's manuals name gas supply, electrode and flue as the things to check.Related: ignition and gas supply
- E134Get it checkedBaxi's "elapsed time — gas valve open without gas": the valve opened, nothing arrived. Check the meter and credit before anything else; it resets from the panel.Related: ignition and gas supply
- E.01.04Stop — call an engineer"Flame loss detected five times in 24 hours": the burner keeps lighting and going out on a Baxi 200/400 Combi or Combi 2. Gas pressure, valve calibration, flue or electrode — an engineer's list.Related: ignition and gas supply
- E09Get it checkedGas valve connection cable fault on the 600, 800, Compact and Duo-tec 2. The board cannot talk to the valve. Baxi allow one reset; a repeat means the wiring or the PCB.Related: ignition and gas supply
Own a Baxi boiler? Save it and its codes come first next time.
Related guides
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
- Manufacturer support portal
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.