High
49 on Ideal Mexico Super CF3 40-80

Your boiler is unable to start the small flame needed to ignite the main burner, meaning your heating and hot water will not work.

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

PILOT WILL NOT LIGHT

From this model's manual
Verified against the Ideal Mexico Super Cf3 40 80 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's small pilot flame fails to stay lit, which is necessary to safely ignite the main heating burners. The most common reasons are a buildup of soot blocking the tiny gas nozzle or a worn-out sensor that can no longer detect the heat from the flame.

This issue often surfaces in autumn when the boiler is switched back on after being idle all summer, as dust or debris can settle in the pilot assembly during the warmer months.

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 49: 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 guides you might find useful

Pilot light keeps going out

Older boilers — thermocouple, draught, gas supply.

Read →

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →