High
NEON6 on Glow-worm Micron 40FF

Your boiler is failing to light or stay lit, meaning it cannot heat your home or 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.

What the manual says

Manufacturer manual

FLAME FAILURE

From this model's manual
Verified against the Glow Worm/Glow Worm Micron 40ff 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.

What causes this fault?

This fault occurs when the boiler attempts to start up but cannot detect a stable flame after several attempts. The most common reasons are a worn ignition electrode that can no longer spark correctly, or a faulty gas valve that isn't allowing fuel into the burner.

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
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like NEON6: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

NEON 1View →NEON 3View →

All 17 fault codes on the Micron 40FF

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

Burner Lit LEDBurner On neon offIlluminated reset lightLED 1 (RESET) Constant LightLED 1 Fast Flashing (8Hz)LED 1 Slow Flashing (2Hz)LED 2 Burner LitLED 2 Fast Flashing (8Hz)NEON1NEON2NEON3NEON4NEON5Reset lightReset light (illuminated)Reset Light / Overheat

Related guides you might find useful

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

Pilot light keeps going out

Older boilers — thermocouple, draught, gas supply.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →