S.15
FAULT CODE
Vaillant
DHW Mode — Pump and Fan Overrun
Low Severity
DIY Check Possible
Status code: Both the pump and fan are running after a DHW cycle to cool the heat exchanger.
Step-by-Step Fix Guide
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Step 1
No action required — this is normal post-DHW 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.