Error FA 364

Safety precautions:

1) If you smell gas (rotten egg / sulfur smell) or hear a hissing leak, evacuate the property immediately, avoid using electrical switches or phones inside, and call your local gas emergency number immediately (in the UK call 0800 111 999). Do not attempt to relight the boiler or operate gas appliances.

2) If there is no smell of gas, keep the area around the boiler well ventilated. Do not try to run the appliance while a gas-valve leak is suspected.

3) Only a Gas Safe registered engineer should isolate, test, repair or replace gas valves and associated gas pipework.

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

1) Note the exact error code and any other codes shown. Photograph the display for the engineer.

2) Attempt a single reset of the boiler using the boiler’s reset button or control panel. If the fault returns immediately or after a short run, stop resetting — repeated resets are unsafe.

3) Check for obvious signs of water leaks, damage, or corrosion around the boiler and gas connections. Do not touch pipework or components.

4) Listen for any unusual hissing from the boiler area and check for any unusual smells. If any signs of gas leak appear, follow the evacuation instructions above.

5) Check that the appliance has power and the gas supply to the property is on (if you know how to safely check the external meter valve). Do not operate internal gas isolation valves unless you are competent and authorised to do so.

Diagnostic and next steps (for homeowner to prepare for engineer):

1) Record when the fault first appeared, what the boiler was doing (heating, hot water, idle), and any recent works, service history or power cuts. This information helps the engineer.

2) Leave the boiler switched off and isolated from use until a Gas Safe engineer attends. Do not attempt internal repairs or remove covers.

3) When the engineer arrives they will check flame sensing/ionisation circuit, verify the FA 364 leak test procedure, and confirm whether the EV2 solenoid is not sealing. Typical professional checks include: checking wiring and connectors between the gas valve and PCB for damage or loose connections; running diagnostic leak tests from the control box; measuring valve coil resistances; checking for contamination or debris in the valve seat; and confirming the PCB/IGN control outputs are correct.

4) If the gas valve itself is faulty or not sealing, a Gas Safe engineer will replace or repair the gas valve assembly and then re-run safety and leak tests and full commissioning. If wiring or the control PCB is found to be at fault, those parts will be repaired or replaced and tested.

Important final notes:

1) FA 364 is a safety lockout and should be treated seriously. Do not attempt gas-valve repairs yourself. Contact a Gas Safe registered engineer to investigate and repair the fault.

2) If you detect any sign of an active gas leak, evacuate and call the emergency gas number immediately. If there is no leak smell but the boiler is locked out, call a Gas Safe engineer and provide them with the fault code FA 364 and the boiler model so they can bring appropriate spares and test equipment.