- Q.I have a leak in my recently
installed radiant tubing, no doubt caused by freezing
last winter before the system was fully operational.
The tubing is a 300-foot run buried in a 4-inch
concrete slab. Is there some kind of "stop leak" that
can be circulated in the system to plug the leak? Is
there a way to locate the leak?
A.John Siegenthaler, a
consulting engineer specializing in hydronic
heating system design in Holland Patent, N.Y.,
responds: As far as I know, there's no product
that can be circulated through any type of radiant
tubing that will stop a leak. So you'll have to cut
out the damaged tubing and splice in a new
section.
First, though, you have to find the leak. The
only reliable method I know is to run warm water
through the system and view the slab with a thermal
imaging camera; the leak will appear as a plume
spreading out from the tubing. This will work best
if the slab is relatively cool when the test is
initiated.
Once you've located the leak, mark the location
on the slab, chip away the concrete to expose the
tubing, and patch the leak. Check with the tubing
manufacturer for the required fittings and
procedure to do the repair, and be sure to
pressure-test the circuit before patching the
slab.
The hardest part of this process may be locating
a thermal imaging camera. Unless you have access to
one owned by a local utility, volunteer fire
department, or other agency, you'll need to
contract with an infrared inspection service.