Potterton DHW Priority / Diverter Valve Fault

No hot water from taps but central heating works normally (combi boiler)

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Safety Warning

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.

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Possible Causes

Stuck diverter valve, Faulty DHW flow sensor, Blocked plate heat exchanger, Motorised diverter head failure

How to Fix / Troubleshooting

Safety first: Turn off power and close cold water isolation valve before removing DHW components.

User checks:

  • Run a hot tap fully open and observe if the boiler fires or displays a tap symbol.
  • Check that cold water pressure is normal.

Engineer checks:

  • Test the DHW flow sensor for correct operation and replace if not detecting flow.
  • Inspect and exercise the diverter valve; replace the motor head or valve body if stuck.
  • Clean or replace the plate heat exchanger if blocked with scale or sludge.

Restoring DHW flow sensing and diverter operation will bring back hot water.

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Repair Difficulty

Hard 4/5

Required Part

Diverter Valve Assembly
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