S.09
FAULT CODE
Vaillant
Status: Burner Off — Anti-Cycle
Medium Severity
DIY Check Possible
The boiler burner is off due to an anti-cycling delay. This prevents the boiler from short-cycling and is normal behaviour.
Step-by-Step Fix Guide
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Step 1
This is a normal status code — the boiler is waiting before firing again
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Step 2
The anti-cycle timer prevents rapid on/off cycling which wastes gas
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Step 3
Wait a few minutes and the boiler will fire when the timer expires and there is demand
Gas Safe Reminder
Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.