S.08
FAULT CODE
Vaillant
DHW Off (Summer Mode)
Low Severity
DIY Check Possible
The boiler's domestic hot water supply has been switched off, usually via the user controls or a summer mode setting.
Step-by-Step Fix Guide
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Step 1
Check the boiler's DHW temperature dial or control panel
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Step 2
Ensure DHW has not been accidentally switched off in the menu
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.