F.72
FAULT CODE
Vaillant
Flow/Return Temperature Difference Too Great
Medium Severity
Engineer Required
The temperature difference between the flow and return sensors exceeds safe limits. Can indicate a sensor fault or genuinely poor circulation.
Step-by-Step Fix Guide
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Step 1
Check system pressure first
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Step 2
Bleed radiators
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Step 3 Engineer only
If fault persists, a Gas Safe engineer should test both NTC sensors
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.