Frozen Pex in Concrete

wgs

Building a house in Alaska. House is off grid. Generators waste heat is stored in a Heat Storage tank via heat exchangers.  Had to leave town for three days. Caretaker ran the generator but did not put a load on it so not much waste heat was generated. Two days latter pex manifold froze. When I got back after three days, flow meters on the manifold were broken, and two runs of pex had burst at the slab. Removed flow meters, repaired exposed broken Pex. It appears 4 or 5 of the 11 zones have leaks. One free flows out the bottom of the slab somewhere at about 3 gpm. the other 4 leak slowly thru stress cuts or stress cracks in the slab at about 1/8 to 1 cup per hour. Used a Fluke IR camera and marked out the PEX. Reading about listening devices to pinpoint the leak.  Need advise on locating the leaks, what equipment works best. And how to best proceed without  doing more damage. There are no professionals in the business at our location. Slab is 51/2 inches with re-bar. 

NRT_Rob

shut off leakers

and if this is one big open area, maybe you could even just abandon the broken loops.



otherwise to do by sound you need very high pressures (over 100+psi) and a stethoscope and a lot of patience.



IR camera should detect "pooling" though if you can watch the system through a "start up" situation.



maybe you'll get lucky and not need a major jackhammer/repour. good luck...

NRT_Rob

also

I would suggest using glycol antifreeze in the system next time around. Off grid in alaska, there is no ifs ands or buts, you need antifreeze.

wgs

antifreeze

Rob

Antifreeze is ordered, 135 gallons. Had to run with water due to system not complete and needed the cooling for the generator. I am isolating the leaks. Then will run the system for the next month and see how it works. Zones were installed in parallel with feeds at opposite ends. After that will make the decision on what needs to be done.

Thanks.