Gledhill Over‑Temperature at Outlets

Hot water temperature at taps is dangerously high from a Gledhill cylinder

Advertisements

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.

Advertisements

Possible Causes

Failed or incorrectly set thermostatic mixing valve, Cylinder thermostat set too high or failed closed, Bypassed blending valve, Faulty overheat thermostat not cutting out

How to Fix / Troubleshooting

Safety: Risk of scalding. Reduce hot water usage until the fault is rectified. Isolate power to the heater if necessary.

Steps:

  • Check TMV setting: Locate the thermostatic mixing valve and verify its temperature setting. Adjust to a safe outlet temperature (typically 50°C at taps, 44°C in baths, subject to local regulations).
  • Test TMV operation: Run a tap and measure the outlet temperature. If the TMV does not respond to adjustment, replace it.
  • Thermostat check: Ensure the cylinder thermostat is not set excessively high. If the store continues to heat beyond the setpoint, the thermostat or control PCB may be faulty.
  • Overheat protection: Confirm that manual reset overheat stats have not been bypassed. Restore any removed safety devices immediately.

Note: After repairs, verify outlet temperatures at multiple taps to ensure safe operation.

Advertisements

Repair Difficulty

Hard 4/5

Required Part

Thermostatic Mixing Valve
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements