Protherm Underfloor Heating Control / Actuator Issue

Underfloor heating controlled by the thermostat is slow to warm up or some zones remain cold.

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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

Air in underfloor circuits, Faulty thermal actuators on manifold, Incorrect zone assignment in thermostat, Floor sensor misplacement

How to Fix / Troubleshooting

Safety: Work on the hydraulic manifold should be done by qualified personnel. Surfaces may be hot.

  • Step 1 – Check thermostat zone configuration:
    • Ensure each room/zone is correctly mapped to the corresponding actuator output.
  • Step 2 – Verify actuator operation:
    • At the manifold, check that the Protherm-compatible actuators open when the thermostat calls for heat.
    • Replace any actuators that do not move or heat up.
  • Step 3 – Bleed air from circuits:
    • Have a heating engineer bleed air from underfloor loops to restore flow.
  • Step 4 – Check floor sensor placement:
    • If the sensor is too close to the pipe, it may shut off heating prematurely.
    • Reposition if possible using the conduit.
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Repair Difficulty

Hard 4/5

Required Part

Protherm-Compatible Underfloor Heating Actuators
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