Unlike wet underfloor heating, electric underfloor heating cannot be controlled with just an Electric Switch and a Room Sensor/Thermostat. This is because the temperature of wet underfloor heating is limited by the boiler output temperature and a mixing valve on the manifold. If electric underfloor heating is left on constantly, it will continue to heat up the floor, and may damage the surface or injure the occupant of the room. Therefore a floor-limiting thermostat must be installed to stop the floor from getting too hot.
The Genius Hub system can control these types of underfloor heating to a schedule, measuring against the air temperature, whilst providing floor temperature limiting. This is done using the Powered Room Thermostat (HI-PRT-A). It is a wired thermostat which can control up to 16A (230V) of electric underfloor heating, or a zone valve/circulation pump for wet underfloor heating. As well as an internal air sensor, a floor sensor can be purchased separately to enable the floor limiting feature. The floor limit is set to 28°C. The recommended position of the floor probe is to be equal distance between the electrical resistive cables/element, or the wet pipes in the floor. It is recommended that the floor probe is placed in a conduit approximately 300mm into the zone that it is controlling, so that if it were to fail, the floor does not need to be lifted to replace the probe
In the app, you can set the schedule to control the air temperature throughout the day, and the Powered Room Thermostat retains local control of the floor limiting, to ensure the floor doesn't overheat should there be a communication problem between the thermostat and the Genius Hub.
The Electric Switch must not be used as a floor limiting device, as the relay is controlled by the Genius Hub, so the floor may overheat if communication is lost between the two devices.
Tips for using electric underfloor heating in a bathroom or wet room:
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All wiring must be in accordance with BS 7671 (IET Wiring Regulations, current edition).
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The Powered Room Thermostat must be placed inside the room it is controlling, as it measures and controls to the air temperature. If the thermostat is placed inside a bathroom, its position must comply with the bathroom zone requirements of BS 7671.