BoilerFaultCodesWhat the manual says
Manufacturer manualignition
From this model's manual
Verified against the Glow Worm Ultracom 2 Sxi installation & service manual, page 55.
What causes this fault?
This fault occurs when the boiler attempts to light the burner but fails to detect a stable flame after several tries. The most common reasons are a worn-out ignition probe that can no longer create a spark or a blockage in the gas supply preventing fuel from reaching the burner.
This issue often surfaces during the first cold snap of autumn when the boiler is forced to work harder after sitting idle throughout the summer.
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 S.03: no call-out fees, no surprise bills.
Approved partner
Get a quote →
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Affiliate links. We may earn a commission at no extra cost to you.