BoilerFaultCodesWhat the manual says
Manufacturer manualAdjust CO2. Set the CO2 content.
Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
What causes this fault?
This fault occurs when the boiler's sensors detect an incorrect mixture of gas and air during the combustion process, meaning the flame is not burning as it should. The most common reasons are a drifting gas valve that needs recalibration or worn-out spark electrodes that are struggling to ignite the gas cleanly. In some cases, it can be caused by a fault in the main control board failing to manage the gas flow accurately.
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.62: 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.