Potterton Cross-Flow / Motorised Valve Fault

Radiators get hot when only hot water is demanded (combi or system with 3-port valve)

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 3-port valve, Passing diverter valve, Incorrect pipework connections, Faulty valve motor head

Safety first: Isolate power and close isolation valves before working on valves.

User checks:

Note when radiators heat up (e.g., only during hot water use) and report to the engineer.

Engineer checks:

Inspect and test the 3-port or diverter valve for correct movement and port sealing.
Replace the motorised head if it does not drive to the correct position.
Replace the valve body if it is passing internally.

Correct valve operation prevents unwanted heating and improves efficiency.

Medium 3/5

3-Port Motorised Valve or Diverter Valve

Check Price on Amazon

We may earn a commission from links on this page.