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Radiant Floor Heating/Leak in pex under cement in sand

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Question
My pex in in the sand under the cement floor. The cement man put 2 inch insulation 2ft down to insulate one part of my floor in case I want heated storage and cold storage one day. For now I am heating all of my 50x50 storage shed with a waste wood boiler. Two zones leak and one drops air pressure quick and the other slow. My air fitting did not leak and I monitored them with a soap mixture. I think it is likely the leak for both is in the ares of the insulation buried where both these zones run through this area. I lost a lot of water and that winter a small service door heaved up and did not fit leading me to believe the water traveled along this joint partitioning the two floors. Should it put high pressure and high volume of air and listen for the leak? Don't want to dig up cement unless I am sure.
Got ideas?

Answer
Badger Radiant Designs
Badger Radiant Designs  
Sorry to hear about your problem but it makes a good argument for professional design. We hear a lot about "radiant storage". Very popular in North Dakota to save that cheap off-peak lecticity don't ya no?

The concept of storing heat underground makes sense, but the crude application you describe leaves most wanting more comfort, among other things; like a way to find the highly unusual leaks you describe. Frankly, this type of jerry-rigged radiant floor heating system gives the category a bad name and gives its detractors more to talk about.

I would not waste time on a marginal system such as you describe. Instead look to wall and ceilings for radiant comfort, or do as so many wood boiler people do and put in one of those awful forced-air hot water fan coils. They aren't as comfortable or efficient as a properly designed and installed radiant slab, but beats freezing all to heck.

On radiant slab systems that have failed for good reason, such as 50 year old copper or steel piped slabs, we often insulate the existing slab, staple PEX to the insulation and pour concrete over all. We also design over-pour systems using several systems that incorporate insulation and PEX positioning all in one.

First, a proper heat load and radiant design.

PS Sand is not a building material nor a good heat sink. It is best used in a sand box for the kids.  

Radiant Floor Heating

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Morgan M. Audetat

Expertise

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...........

Experience

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 owner---www.BadgerRadiantDesigns.com---Minneapolis 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.

Education/Credentials
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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