College Park, Md. — I was in the middle of planning and building a solar exhibit for a Boy Scout Jamboree just a few weeks prior to the Solar Decathlon in Washington when I received this e-mail from Tyler Sines, the Mechanical Team Leader from the University of Maryland:
I recently read your article on www.contractormag.com titled, “The art of hydronic radiant leak detection. I am writing you in hopes you may have some advice for my particular situation. I am a Mechanical Engineering student at the University of Maryland working a project for the 2007 Solar Decathlon in which University teams around the world are challenged to build a fully functional 800-sq.ft. home that is solely powered by solar energy (www.solarteam.org). To heat the house we're using a radiant floor composed of aluminum-PEX tubes embedded in a Warmboard subfloor. Our finish floor is a solid hardwood (Tigerwood to be exact).
Unfortunately when the flooring subcontractor installed the floor we believe he may have punctured one of the tubes. The system was air-pressurized during the flooring installation but the puncture was not immediately noticed (most likely due to the speed that the crew was working added to the noise of their own air compressors that would have dulled the sound of an air-leak in the floor).
Long story short, we have a leak in one of our radiant loops and are curious as to the best way to find the leak and who would be the best person to contact to help find the leak, or if it is possible to pinpoint the leak ourselves with the help of some specialized equipment that we would be able to rent somewhere.
One other factor that we have going against us is time — we need to be ready for the competition by the end of September which would have to include the repair of the flooring. Any advice you may have on this situation would be greatly appreciated.
Tyler and I exchanged e-mails and I offered to visit with an ultrasonic leak detector that I'd lend to them.
Warmboard! I knew from experience the folks there typically produce CAD drawings that illustrate the exact location of the radiant tubing. With the flooring contractor refusing to render assistance, that CAD drawing would be very useful information.
Warmboard's (www.warmboard.com) Casey Kunselman was quick to respond with the drawings and a phone call where I discovered that good friend Dan Foley, president of Foley Mechanical Inc. in Arlington, Va., was the team's advisor for the hydronic radiant heating! Dan told me that he'd bring two of his ace mechanics along for the scheduled Saturday visit.
Imagine my surprise to find a team of college students hard at work before 8:00 AM! Tyler Sines introduced me to team members John Kucia, Dan Zimmerman, Darrell Smith and Amy Gardner, the faculty advisor overseeing the project. Their stress level was high, given the looming deadline and a radiant system that wouldn't hold its air-charge.
Dan Foley arrived next with ace mechanics Papa Duric and Bill Dooly in tow. They quickly set up shop at the exterior mechanical space and helped students assemble portions of the hydronic system piping. 100-PSI air was rapidly dropping — much too fast for this to be just a single leak! The pressure was repeatedly boosted with hopes of success using the ultrasonic leak detector. Warmboard's drawing revealed a number of loop-returns were hidden under an island cabinet and the kitchen sink cabinets — the only spots where tubing return-bends could seek refuge from the ultrasonic detector. Gas was injected into the tubing and a hyper-sensitive gas-sniffer was almost immediately able to generalize the area we'd suspected — under the cabinets.
The island cabinet was constructed using concrete walls, so it could not be removed and the kitchen cabinets had been built in place. Time to remove flooring!
John Zimmerman tackled this with gusto and had the first strip of Tigerwood removed — a careful surgical procedure in order to keep from damaging neighboring strips of hardwood or the PEX-Al-PEX sandwiched below. Carefully fanning away the gas mixture, they were able to pinpoint six return bends that had been punctured by staples, not nails, so that most likely meant the tubing was punctured in six to 12 places. The floor-space between the kitchen cabinet and island sink did not warrant anything more elaborate than abandoning the affected loops and routing a straight tube-run to splice into opposite sides of the leaks. Come Sunday, the system was still holding its 100-PSI charge! The race to the finish was back on track.
While the students had been working on the leak issues, I'd had an opportunity to talk with Faculty Advisor Amy Gardner. Gardner had become involved with the 2005 decathlon project and, in the process, had caught the “solar bug.” The low point for Gardner and the Maryland team was the punctured tubing and the flooring contractor's absence of assuming any responsibility.
Lessons learned from the school of hard knocks — lessons you won't get in a classroom — can be invaluable.