Gledhill Pump or Fan Running Continuously

Gledhill unit makes a constant running noise even when there is no demand for hot water or heating

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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 relay on PCB, Incorrect wiring providing permanent live, Faulty flow switch falsely indicating demand, Control logic error

How to Fix / Troubleshooting

Safety: Isolate power before inspecting wiring or PCB.

Steps:

  • Confirm no demand: Ensure all programmers, thermostats, and hot taps are off/closed. If the pump or fan still runs, a control fault is likely.
  • Flow switch test: Disconnect the flow switch signal from the PCB. If the pump stops, the flow switch may be stuck or faulty and should be replaced.
  • Wiring check: Verify that the pump/fan is not wired directly to a permanent live instead of the PCB output.
  • PCB relay: Inspect and, if necessary, replace the PCB if the output relay is welded closed.

Note: Continuous running wastes energy and can shorten component life; resolve promptly.

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Repair Difficulty

Medium 3/5

Required Part

Flow Switch
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