Baxi E15 fault codewhat it means and how to fix it
Gas valve fault on the digital-display Baxis — "gas valve command fault" on Baxi's professional page. One reset is allowed; after that it is the valve or the board.
Take care
Get a Gas Safe registered engineer to look at your Baxi E15
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 E15 means
E15 is the second entry in the Baxi digital-display table, "Gas valve fault", and Baxi's professional page refines it to "Gas valve command fault": the board sent a command to the valve and did not get the response it expected. It differs from E09 by a step. E09 is the cable between board and valve testing as open; E15 is the cable apparently intact but the valve not doing what it is told. The 600 and 800 manuals include E15 in the sentence "09 followed by 15 or 384 indicates possible faulty components", allow it to be relit by "pressing the Reset button for 1 to 3 seconds", and in the fault-finding flow send the engineer down the same path as E09: check all PCB connections, then replace the PCB.
In practice the order of suspicion is the valve first, because a gas valve on a boiler ten years old has done several hundred thousand cycles and its solenoid or the modulating coil can fail while the cable is perfectly good, then the board.
On the 600 and 800 the valve is Baxi part 7683968, a sealed unit that is replaced complete and set up with a combustion analyser afterwards. The boiler will not attempt ignition while E15 is showing, so the code is safe in the sense that no gas is passing; it is not a code to clear repeatedly, because each reset asks the valve to try again and a valve that is sticking rather than failed outright may one day answer late instead of not at all. Selector-switch Baxis do not print E15.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Gas valve solenoid or modulating coil failed | The valve receives the command and does not move, or reports a position the board rejects. Replaced as a complete unit and re-commissioned with a combustion analyser. | Common |
| Connector or cable intermittent | A connection good enough to pass the continuity check but not to carry the drive current. Baxi's instruction to "check all PCB connections" catches this before any part is bought. | Occasional |
| PCB drive circuit | If the valve and its cable test good, Baxi's flow ends at the board. The drive and monitoring for the valve is on the PCB and is not repairable separately. | Occasional |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£80–£450
Time on site
1 hour
Connection repair £80–£150. Gas valve (Baxi 7683968) fitted and set up £280–£450. 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 gas valve
7683968£120–£240Authorised 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.