Home/Boiler Fault Codes/Vaillant F75
VAILLANT FAULT CODE
Vaillant F75
The boiler didn't detect the expected change in water pressure when the circulation pump started. This can point to genuinely low system pressure, a failing pump, or a faulty pressure sensor.
WHAT F75 TYPICALLY INDICATES
The boiler didn't detect the expected change in water pressure when the circulation pump started. This can point to genuinely low system pressure, a failing pump, or a faulty pressure sensor.
WHAT TO DO
Check the pressure gauge and, if it's low, top up via the filling loop following the manual. If pressure is normal and the fault persists, This is not a DIY fix — it requires a Gas Safe registered engineer to diagnose and repair safely.
A NOTE ON GAS SAFE REGISTRATION
Any work on the gas side of a boiler in the UK legally requires a Gas Safe registered engineer, it isn't optional. Our engineers are fully Gas Safe registered, and you're always welcome to ask to see ID on the day. This page is general information about what a fault code typically indicates; it is not a substitute for an engineer diagnosing your specific boiler.
Seeing Vaillant F75 on your boiler?
Tell us the code and your postcode. A fully Gas Safe registered engineer will diagnose the actual cause before quoting a fix.
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