Error E270

Safety first:

1) If you smell gas: stop using any electrical switches, open doors/windows, leave the building immediately and call your gas emergency number or 999. Do not attempt any checks.

2) If you do not smell gas, isolate the boiler electrically before touching any covers. Do not remove burner, gas valve, wiring or PCB covers unless you are a Gas Safe registered engineer.

Initial checks a homeowner can do (non-invasive):

1) Note the exact error code, when it appears and any other behaviour (clicking, fan running, number of lockouts). Photograph the display if useful.

2) Check that other gas appliances (hob, gas fire) work. If nothing else has gas, the issue is likely a gas supply problem and you should contact your gas supplier.

3) Confirm the boiler’s gas isolation cock (usually a lever on the gas pipe to the boiler) is open. If it is off, turn it on and attempt a restart.

4) Check the boiler has mains power and the timer/room stat is calling for heat/hot water. Reset power at the isolator or fuse spur only if safe to do so.

5) Try a single reset of the boiler following the manufacturer’s procedure. Do not repeatedly reset more than once or twice if the fault persists — repeated attempts can mask the underlying issue and create unsafe conditions.

6) Check boiler pressure (usually on the front pressure gauge). Low pressure can cause other faults; top up to the recommended pressure if you know how and it’s safe to do so.

7) Look for obvious external obstructions to the flue outlet and make sure vents/air supply around the boiler are not blocked.

Specific diagnostic observations you can make (do not open the combustion chamber):

1) With the boiler powered and a call for heat, listen and watch the ignition sequence from outside: first the fan may run, then you may hear a click or ignition noise and smell a faint combustion smell if ignition occurs. If you hear repeated clicks and then an immediate lockout or the E270 appears, that suggests ignition is being attempted but no flame is established or detected.

2) If other gas appliances work but the boiler does not, suspect boiler ignition/flame detection or valve/PCB fault rather than the external gas supply.

3) If the boiler attempts to ignite (fan runs, clicking) but you still get E270, note this and do not attempt to access the burner or electrodes yourself.

What to do next and when to call a professional:

1) If initial checks (gas supply on for other appliances, gas cock open, power present, single reset tried) do not clear E270, stop further DIY. This fault implicates gas/ignition components or control electronics that must be tested and repaired only by a Gas Safe registered engineer.

2) When you call the engineer, give them: boiler model, serial number, the exact fault code E270, what you observed during ignition attempts, whether other gas appliances work, and any steps you already tried.

3) The engineer will typically test gas pressure to the appliance, check the gas isolation valve and inlet, verify ignition spark and flame sensing (ionisation probe), test the gas valve and wiring, and inspect the PCB and error history. They will also check for related faults that could produce the same symptom.

4) Do not bypass safety devices, do not attempt to replace ignition electrodes, gas valves or PCBs yourself, and do not repeatedly reset the boiler to force operation.

Summary: perform basic non-invasive checks (gas supply, isolation valve, power, one reset, pressure check) and if E270 remains, arrange a Gas Safe engineer to carry out electrical and gas-side diagnostics and repairs. This protects both safety and the longevity of the appliance.