I have purchased two SunTouch UnderFloor 16" x 6' long 120V 0.6A to retrofit a radiant floor on the one-level-above bathroom without having to remove the floor. The instruction manual (page 4) indicates that the SunStat floor sensor "must be installed in the floor with the mat". However, my preference would be to control the heating using a 3rd-party thermostat which would trigger based on the ambient temperature in the bathroom.
Does anyone have experience with such system, or explanations as to why the SunStat floor sensor would be absolutely required, as opposed to an ambient temperature thermostat?
Thanks for the help!
Best Answer
Because the radiant floor could get too hot while the external temperature sensor still indicates below required T.
This could damage the element or part of the floor.
The underfloor heating (water) I fitted had two temperature sensors - one for the ambient and one at the output of the mixing valve to shut down the pump if the output was above a certain value so the pipes did not get damaged through overheating.