BoilerFaultCodesWhat the manual says
Manufacturer manualIgnition sequence (hot water operation)
From this model's manual
Verified against the Vaillant Ecomax 613 installation & service manual, page 45.
What causes this fault?
This code appears when the boiler begins its internal sequence to heat the water for your taps or cylinder. It is triggered by the system's sensors detecting a demand for hot water, signaling the fan to start and the gas valve to prepare for ignition. This is a standard part of the boiler's operation and does not indicate a breakdown.
DIY fix possible
No action required; this is a normal status messageWait for the boiler to complete its ignition sequenceMonitor for any transition to a fault code (e.g., F.28 or F.29) if ignition fails
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.13: 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.