S.28
FAULT CODE
Vaillant
DHW Mode — Anti-Cycle Timer
Low Severity
DIY Check Possible
Status code: The boiler is in its anti-cycling period between hot water calls.
Step-by-Step Fix Guide
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Step 1
No action required — normal boiler behaviour
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.