Boiler displays F75 on start-up, pump runs but no pressure change detected

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Stuck or failed pump, Blocked pressure sensor connection, Faulty pressure sensor, Air in pump or system

Safety first: Isolate power before bleeding the pump or opening any components.

Steps to check:

Check system pressure and top up if low.
Bleed radiators and any automatic air vents.
Bleed the pump via its front screw (if fitted) to remove trapped air and confirm the shaft turns.
Tap gently on the pressure sensor body and check its connection to the hydraulic block for blockage.
Reset the boiler. If F75 persists, the pump or pressure sensor may require replacement.

Warning: Water may escape when bleeding the pump; protect electrical parts from moisture.

Medium 3/5

Circulation Pump / Water Pressure Sensor

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