BoilerFaultCodesWhat the manual says
Manufacturer manualStepper motor fault (gas valve)
From this model's manual
Verified against the Glow Worm Ci Range installation & service manual, page 34.
What causes this fault?
This fault occurs when the boiler's internal computer is unable to communicate with or move the motor that controls the gas supply. The most common reason is that the motor has physically jammed or its electronic windings have burnt out, preventing the valve from opening to let fuel in for ignition.
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 15: 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.