Medium
Flame slow to stabilise during start up on Grant Vortex 15-20

Your boiler is struggling to establish a steady flame when it first turns on, usually because it isn't getting quite enough air or fuel to start smoothly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Insufficient air supply, incorrect nozzle, low fuel pressure, or insufficient draught

From this model's manual
Verified against the Grant/Grant Vortex 15 20 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

LockoutView →Flame failureView →

All 12 fault codes on the Vortex 15-20

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

26.036.0Boiler operating on overheat thermostatBoiler will not startBurner lock-outBurner pulsatesCombustion fumes smellFumes and puffing during startingOil odoursVisible smoke from flue or high smoke numberWater temperature low

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