Error F.61

Safety first

1) If you smell gas anywhere in the house: do not operate switches, do not use phones or naked flames. Evacuate everyone immediately and call the gas emergency number (UK: 0800 111 999) from a safe location.

2) If the boiler is locked out and there is no gas smell, do not repeatedly press reset. Repeated resets can mask a dangerous fault and are not a fix.

Initial checks a homeowner can safely perform

1) Record the fault: write down or photograph the boiler model, serial number and the F.61 display and any other indicators or LEDs.

2) Check other gas appliances: confirm whether other gas appliances (cooker, gas fire) are working. If none work, there may be a gas supply issue and you should contact the gas supplier.

3) Check the gas isolation valve to the appliance (external to the boiler) is open if you know where it is and can operate it safely.

4) Check mains electrical supply and boiler fused switch: ensure the boiler has power and the switched fused spur hasn’t tripped. Switch off and back on if safe to do so.

5) Try a single reset: follow the boiler’s manual reset procedure (typically press and hold the reset button for up to 10 seconds). If the boiler restarts and runs normally, monitor it. If F.61 returns, stop resetting and proceed to call a professional.

6) Do a visual external check only: look for obvious signs of damage, water ingress, burn marks or loose external wiring where visible without removing the casing. Do not open the boiler or probe internal wiring yourself.

What a Gas Safe engineer will do (diagnostic and repair steps)

1) On arrival the engineer will isolate gas and electrical supplies and perform a safe, full inspection.

2) They will read fault memory and live diagnostics from the PCB to confirm whether the fault is intermittent or persistent and check for related fault codes.

3) Wiring harness inspection and testing: they will check the harness and connectors between the PCB and gas valve for short circuits, corrosion, damaged insulation or loose connections and test continuity and insulation resistance with appropriate instruments.

4) Gas valve checks: measure coil resistance, check actuator movement and mechanical freedom, and verify correct signals from the PCB to the valve. If the valve is seized or mechanically stuck they may attempt to free it; if electrical/mechanical failure is confirmed the valve will be replaced.

5) PCB testing: if wiring and valve appear good, the engineer will test PCB outputs and communications (e.g. eBUS or control signals). A defective PCB that cannot drive the valve correctly will be replaced only after confirming other causes have been eliminated.

6) Gas supply and pressure checks: confirm inlet gas pressure and that gas is being supplied correctly to the appliance; ensure no partial supply or regulator issues are present.

7) Leak and safety checks: after any repair or replacement the engineer will perform combustion checks, tightness tests and full commissioning, then clear faults and verify safe operation.

Important notes and next steps

1) Do not attempt internal repairs: gas valves, PCBs and internal wiring must only be handled by a Gas Safe registered engineer.

2) When you call the engineer, give them the boiler model, serial number, the F.61 code, any other codes, what you tried (reset, gas checks), and whether you smell gas or have no gas to other appliances. Photos are helpful.

3) If the fault reappears after a repair, stop using the boiler and call the installer/engineer back. Repeated lockouts indicate the root cause hasn’t been addressed.

4) Regular annual servicing reduces the chance of developing faults like seized valves. If the boiler is older (many manufacturers suggest considering replacement after a decade or more), discuss long-term reliability and replacement options with your engineer.

Remember: F.61 is a safety-related gas-valve/communication fault. Safe initial checks can be done by the homeowner, but diagnosis beyond visual and supply checks, and all repairs, must be done by a Gas Safe registered engineer.