Radiant Floor Heating/PEX leak in concrete


Situation is a small house, only a year old or so, with radiant in floor heat - Pex tubing embedded in concrete fed by a boiler system.  There are two loops in the floor, not sure of the lengths. The house suffered a freeze up, not sure how cold it got but could have been as low as zero to five deg F.  When we discovered it the floor temp was between 20 and 25 degrees (measured with IR thermometer). We determined that no antifreeze was present in the system. We fear that one of the Pex loops has broken. Pressure tests show one holds pressure, the other does not.  Also what appears to be seepage from an area of the concrete floor about six feet away from the manifold, possibly running under a wall separating the boiler room from the kitchen. While we fear the worst, we also don't know what to do at this point and are unfamiliar with whether even the possibility exists to repair a leak. Any suggestions would be most appreciated as we are pretty much in despair at this point.

BadgerBoilerService.com PEX repair slab

BadgerBoilerService.com panel radiator
The water in the PEX that has been frozen in a concrete slab, as apposed to PEX frozen in free air, will almost always burst a hole in the PEX wall resulting in a loss of pressure to the radiant floor heating system (lower or no pressure at the boiler gauge).

Naturally this can happen in any hydronic heating system due to poor installation (most of our frozen heating system calls are for fin-tube baseboard and frozen cast iron radiators). The first call should be to a competent hydronic heating professional to assess the damage and proscribe a cure. The second call is to your insurance agent.

Remembering that the freeze was caused by cold weather, human error or equipment failure one has to ask why. We sell freeze alarm strategies that will call alert the homeowner of any low temperature in the house. This negates the often ill-advised use of anti-freeze in residential boiler heating systems, which lowers pump and heat transfer efficiency.

Now to the leaking radiant floor slab. Dig it up. Find the leak and repair it using the PEX tubing manufacturer's fittings and procedure. When designing and installing radiant slab systems we never bury a fitting in concrete, but we have many repairs now more than a decade old. It is rare event, but we do a lot of radiant floor heating.

It is useful to note that most radiant slabs are have more than enough tubing to heat a home even when a loop is dead. We also design retrofit radiant ceiling and use panel radiators for old copper radiant floor heating systems that cannot be repaired.  

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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 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.

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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