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Radiant Floor Heating/hydronic floor heat sensors


We are currently figuring out where to put the floor sensors in our 2 zones.  The tubes are in a concrete slab.  Floor will be brick in 1/2 inch of sand.  How often, in general, do the sensors fail?   Do we buy and install extras now and run them to the utility room?  Also:  When a sensor fails what happens to the system?   Too much heat, no heat?  If the sensor is controling the circulation pump, is there poor control or no control?   Thanks you very much for your time !

We use floor sensor to help control radiant floor panels on a regular basis and have found most to be quite reliable. Care must be taken to place the sensor (thermistor) carefully between radiant tubing  or electric heating cables. We usually use a conduit to protect our floor sensors, and facilitate replacement should the need arise.

For thinner electric floor heating, typically too thin for any conduit, we install two sensors reserving one for backup should the first fail. We use variations of this control device to melt snow on driveways.

When a thermistor fails it will usually fail to call the heat on.

Thermistor, like hydronics, is a portmanteau; combining thermal and resistor. Think of it as a thermal light switch.

As for what it controls and how, the possibilities are endless. Most often we simple use them to keep a radiant surface at a certain temperature or bracket the temperature of the floor working in conjunction with an ambient (room air) thermostat our preference for the control of most residential radiant floors, walls and ceilings.  

Radiant Floor Heating

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Morgan M. Audetat


Radiant panel heating design, including floors and ceilings, European wall panels and snow melting for residential and light commercial buildings..............................................................-Master of Steam and Hot Water,City of Minneapolis....................................................--- Master Plumber, State of Minnesota...........


30 years..... Charter Board Member - Radiant Panel Association, former manufacturer of condensing boilers, former national distributor of radiant floor products, son and apprentice of mechanical & plumbing contractor. Current mechanical/plumbing contractor specializing in hydronic based, integrated HVAC systems. Radiant floor heating/cooling. Snow Melting. Condensing Boilers. Indirect water heaters. System design, consulting and technical training world-wide. Licensed contractor, designer, installer and consultant.

B.S. University WI 1981 CONTINUING EDUCATION: Viessmann Condensing boiler and Solar water heating certification 2010, N.D.S.U. Lead Worker RRP certification 2010, Knight condensing boiler certification 2009, Wrightsoft Manual J CAD certification 2009, RPA Designer & Installer Certification 2008, Nate Hydronic/Forced Air Certification 2008, Uponor/Wirsbo advanced design school certification 2007, Buderus Wall-hung certification 2007, Power Limited License (low voltage controls) 40 CE credits 2005, Basic Hydronic Certification IPEX & Northern Alberta Institute of Technology 1998, Charter Board Member - Radiant Panel Association 1994, Residential Off-Electric to Hydronic Conversion Heating School Canadian Hydronics Council 1994, B&G Little Red School House 1993, Rood Utilities (now Auburn Technical Institute) Oil Burner School 1993 ,Tekmar Controls residential and commercial 1993, Division Manager and Advanced Hydronic Seminar Instructor for the first Exclusively Hydronic Radiant Floor Distributor in the USA 1990, Hydronic Radiant Heating Association Workshop participant with Richard c. Bourne, PE spring 1988, Master Plumbing, Hydronic, Solar Course Red Rocks Community College 1987.

Awards and Honors
2009 System Showcase Award - Radiant Panel Association

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