S.00
FAULT CODE
Vaillant
Temperature Too High (Blocking)
Medium Severity
Engineer Required
A blocking (non-lockout) status code: flow temperature is too high. The boiler will wait until temperature drops before restarting.
Step-by-Step Fix Guide
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Step 1
Check system pressure
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Step 2
Bleed radiators
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Step 3 Engineer only
If S.00 appears frequently, call a Gas Safe engineer to check pump and circulation
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.