High Lockout
F.61 on Vaillant ecoMAX 613

Your boiler has detected an electrical problem with the system that controls the gas flow, meaning it cannot light safely for heating or hot water.

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 – defective | Cause: Short circuit/earth (ground) leak in cable loom to gas valves, gas valve assembly defective (earth/ground leak from coils), electronic control system defective

What causes this fault?

This fault occurs when the boiler's central computer loses the ability to safely communicate with the gas valve. The most common reason is an internal electrical failure within the valve's coils or a malfunction on the main control board, which prevents the system from regulating fuel flow. In some cases, it can also be triggered by damaged internal wiring that has developed a short circuit.

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.

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