High Lockout
F.61 on Vaillant ecoMAX Pro 28E

Your boiler has detected a communication problem between the main computer and the gas valve, meaning it cannot safely light the flame to provide heating or hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Gas valve control circuit error

What causes this fault?

This fault occurs when the boiler's main control board loses the ability to send or receive electrical signals to the gas valve. The most common reason is an electronic failure within the circuit board itself, though it can also be caused by loose wiring or a short circuit in the gas valve's internal solenoid.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
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Related fault codes

F.62View →F.22View →F.27View →

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