Emergency
F.27 on Vaillant ecoFIT sustain 630

Your boiler has temporarily shut down because it cannot reliably detect the flame inside, meaning it is currently unsafe for it to keep running.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Safety shutdown: Fault in flame detection

From this model's manual
Verified against the Vaillant/Vaillant Vaillantpro Ecofit Sustain System Installation And Maintenance I installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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Related fault codes

F.28View →F.29View →

All 42 fault codes on the ecoFIT sustain 630

Seeing a different code? Every code this model can display, in one place.

ConnectionF.00F.01F.10F.11F.12F.13F.20F.22F.23F.24F.25F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.73F.74F.75F.76F.77F.78F.83F.84F.85F.86F.87F.88F.89F.91F.97

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