Way to fix possible pinhole leak in copper pipe encased in concrete?

Flotsam

I have a 52 year old Mid-Century Modern home with radiant in-floor heating provided by a boiler and copper piping encased in concrete. I've recently developed a leak (which we've been able to trace to somewhere in the 1 1/2" return line from the living room loop back to the boiler) which is allowing enough air to enter the system such that bleeding is now required every 5 to 7 days. Since jack-hammering the floor up to replace the pipe really isn't an option, before we consider eventually having to abandon the system entirely and attempting to retrofit some kind of forced air system, is there any way to possibly plug what appears to be - at least for the moment - a pinhole leak in encased copper pipe? We've considered the automotive radiator leak fluids for example, but are looking for either experienced advice or other outside-the-box ideas.

Leon82

That probably is not good for the boiler but it may buy you some time. It sounds like you have slab on grade with a finished floor over the concrete. So you probably will need to explore the forced air or baseboard or panel rads

kcopp

Fernox makes this product..
You can give this a try and it will by you some time. You are prob looking at jacking up the floor OR finding a way to get the return out of the floor and above ground.

http://www.fernox.com/products/water+treatment+chemicals/leak+sealers

Zman

Usually you are getting air because water is leaking out and being refreshed with airated water. Air will not enter a pressurized system through a hole.
I would try using an infrared camera to locate the leak and repair.

ratio

You should be able to pinpoint the leak with a thermal camera of some sort, possibly even an IR thermometer. I bought a Fluke VT04 for the purpose & it worked swimmingly. If you can find the leak, a small hole can be opened & the repair made, & you might not have to abandon the radiant floor.

Gordy

May I ask have you isolated the system from make up water to see how long it holds pressure?

How have you traced the leak to the 1 1/2" pipe?

Flotsam

Gordy, the system seems to lose 1 psi every 30 minutes or so, it's hard to say because the gauge we're looking at is old and we don't trust it completely. What brought the issue to our attention in the first place is the need to bleed the system every week or so or else the living room loop pump begins to just freewheel.

Flotsam

As some of you have guessed, the system in encased in a slab, unfortunately under $50,000 worth of Italian tile. Jack-hammering even a small portion is simply out of the question given the inability to match replacement tiles to the original. The surrounding walls are either brick or floor to ceiling glass, so adding baseboards or moving the return above ground is essentially impossible as well. Kind of a perfect storm.

hot_rod

If you are sure it is a leak in a loop, the companies that do pipe relining may have a fix. I read an article where they relined some underground, pressurized glycol PVC chiller lines in Colorado. I'm not sure how small they can reline.

I get "Cleaner" magazine, my wife is in the drain and sewer business, and every month they have unique relining articles.

SWEI

Is this an Eichler by chance?

Flotsam

SWEI, no, Jackson Hallett. Hallett worked with Alden B Dow (a protege of Frank Lloyd Wright) in Midland, Michigan.

SWEI

Sounds like a fun project.

My Dad bought a brand new Eichler in San Mateo just before he got married. I learned to crawl on those heated floors.

We're going to http://www.modernismweek.com/ next year for the first time.

Danny Scully

How is retrofitting forced air more feasible than repairing the leak? Thinking ahead a bit, but just an idea, you can install radiant in a ceiling as well.

Paul Pollets

The problem with older copper RFH systems is that another leak could develop after fixing the first. Concrete embedded piping is deleterious to copper unless it is sleeved or wrapped in mil tape

Jean-David Beyer

If the slab cannot be fixed and baseboard cannot be used, can you use radiant panels on the walls or ceiling?

EBEBRATT-Ed

@Flotsam
google SHALER RINK SEAL PRO

I have never used it myself but I know of a hockey rink where the piping in the slab leaked and this did the trick. Works on copper plastic and steal pipe

nibs

Coming right out of left field, Detroit Diesel has a product which seals pinholes in steel cylinder liners, it may be that it needs the fire of the fuel to cook it, but a call to their engineering dept may yield positive results.
Met a guy who had used it with very good results.
Tony.

billpipe

You can try Boiler Solder by Silverking. It works similar to car radiator stop leak. The product can be put into the system with an old fashioned force pump. It searches out the leak by being drawn to oxygen. This is a one time only application, as too much will build up on the pipe walls just like cholesterol in an artery.