Error E15

Safety precautions:

1) If you smell gas, hear a hissing gas sound, or suspect a leak: immediately evacuate the property, avoid operating electrical switches or phones inside, and call the national gas emergency number (or your local emergency gas service) from a safe location. Do not attempt to fix a gas leak yourself.

2) If the boiler is locked out and behaving erratically, avoid repeated resets more than 2-3 times. Repeated resets can mask a developing fault and may be unsafe.

3) Do not open the burner compartment or attempt repairs involving the gas valve, gas pipework, or PCB unless you are Gas Safe registered.

Initial checks a homeowner can do:

1) Check the gas supply: confirm other gas appliances (hob, gas fire) work. If none work, check your gas meter or prepay meter credit and contact your gas supplier if needed.

2) Check the boiler has power: ensure the boiler display is on and the fused spur or wall switch is on. If the boiler has no display, check the household fuse or RCD.

3) Note the full error display and any behaviour (no flame, repeated attempts to light, lockout). Record how many times it has locked out and any other codes shown.

4) Check boiler water pressure (aim for about 1–1.5 bar on a cold system). Low pressure can cause unrelated lockouts; top up only if you know how and the boiler manual instructs.

Specific diagnostic and simple fix steps you can try:

1) Reset the boiler: find the reset button or selector. On many Baxi models press and hold the reset button for 5–10 seconds or set the selector to R (Reset) and hold for at least 5 seconds. Wait for the boiler to attempt restart and watch the display for E15 reappearing.

2) If E15 returns immediately or after restart: switch the boiler off at the mains isolator for 1 minute, switch back on and try a reset once more. Do not keep resetting more than twice if the fault persists.

3) Visual inspection from the outside only: with the boiler powered off, check around the boiler casing for signs of water damage, burnt marks, loose external connectors, or rodents—these can cause wiring faults. Do not touch internal wiring or components.

4) Check for additional related symptoms: loss of flame, intermittent operation, or other error codes that may indicate PCB communication faults (these help the engineer diagnose).

When to call a professional and what information to give them:

1) Call a Gas Safe registered engineer if E15 persists after a single proper reset and power cycle, if you see signs of wiring or water damage, or if ignition/flame issues are present. This fault typically requires specialist diagnostic tools and safe handling of gas components.

2) When you call, provide: boiler make and model (Baxi 600 Combi), serial number if available, exact error code E15, any other displayed codes, what you tried (reset, power cycle), whether other gas appliances work, and whether you smelled gas or saw damage.

3) Explain you did not open internal components and ask the engineer to inspect gas valve operation, valve-to-PCB wiring, and PCB communication. The engineer may test voltages, swap/bench-test the valve, or replace the valve or PCB as required.

Final note: E15 is not a straightforward DIY repair. It is a gas-control related fault and should be resolved by a Gas Safe registered engineer. If you have any doubt about safety at any stage, stop and contact an emergency gas service or a qualified engineer immediately.