Glow-worm Improper Underfloor Heating Control

Thermostat shows large temperature swings in rooms with underfloor heating

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

Floor sensor not installed or not enabled, Flow temperature too high for UFH, Control set to air‑only mode, Poorly balanced UFH manifold

How to Fix / Troubleshooting

Safety: Isolate power before adjusting any electrical connections. Hydraulic adjustments should be done by a competent person.

Steps:

  • Check whether a floor sensor is installed and connected to the thermostat. If present, enable floor temperature control in the thermostat settings.
  • Set a maximum floor temperature limit appropriate for UFH (typically 27–29 °C) in the thermostat.
  • Ensure the boiler or mixing valve is set to provide a suitable flow temperature for UFH (usually 35–45 °C).
  • Have the UFH manifold balancing checked so that all loops receive appropriate flow.

Remedy:

  • If no floor sensor is installed, consider adding a Glow‑worm compatible floor sensor for better UFH control.
Advertisements

Repair Difficulty

Medium 3/5

Required Part

Glow-worm underfloor floor sensor / UFH control settings
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements