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Radiant Floor Heating/Radiant overshoot and slab sensors


We are maintaining rooms with radiant heat at 70 and keeping the slab at 70 to have a warm floor, however, we are experiencing some overshoot to 74 in a few rooms, especially rooms with solar gain.  Do you think we should maintain the slab at 67 or 65 to avoid the overshoot?

Badger Radiant Designs Tekmar 522
Badger Radiant Designs  
Radiant slab sensors are one of the most over-used and misunderstood radiant floor controls available. I guess I should be selling them (retail) since everyone wants one or wishes they had one.

A radiant slab sensor properly place in a concrete or gypcrete slab, thick or thin as it were, can help facilitate minute control of room (ambient)temperature. This is especially true where extraordinary load swings may occur e.g. your solar gain or in poorly insulated buildings and often in commercial building with "big glass" or open foyers where heavy traffic presents a high predictable load and a secondary or second stage heat source picks up the loads not covered by a fixed slab temperature.

It is very rarely the case, at least in residential radiant slab heating, that a slab sensor is the exclusive control. In almost every case, a room air thermostat is used as primary control and if the thermostat happens to have slab sensing capabilities, such as the Tekmar 522 the upper and lower temperature ranges can be set to "bracket" the slab output helping to control the over and undershooting common in homes with "big glass.  

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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