Possible radiant leak in slab?

Sam G._2

I am a lic. plumber. I live in a house with copper tubing in slab radiant. I stronly suspected a radiant leak in the slab. Not wanting to jack hammer floor ( and other houses in neighborhood that bypassed radiant could not get rooms warm enough with baseboard). I experimented on my own home and added a hydronic system sealer. It took 2 applications over 2 seasons, but it made the system tight again. No pressure drops in a couple of years. I have done the same with several customers in the neighborhood with the same results. Not a perfect solution, but it worked.

Mike Clements

Possible radiant leak in slab?

I'm a simple homeowner with no heating skills what-so-ever.

Last winter the pressure in my boiler had dropped to zero. A heating contractor came out and said that the pressure reducing valve was clogged and that there was a leak in the radiant piping in the slab. He replaced the valve and freed the pump, which had seized from running with no water circulating through it.

A few weeks ago I shut off the city water feed to the boiler and left the pump running, but did not have the heat on, since it was hot out. After seven days the pressure had dropped from 20 to around 15. Does this mean I have a leak somewhere? The reason I ask is that I read a response from Dan to a similar question in which he stated that when doing this, I should see a considerable drop in pressure within an hour, while I'm losing less than 1 psi per day.

The heating contractor suggested bypassing the radiant pipes and running baseboard convectors along the basement wall and in the bathroom.

I'd hate to give up the radiant heat in the slab.

If there is a leak, could it be worth fixing?

If it's worth fixing...any suggestions? I can't seem to find anyone qualified in the Chicago area.

Thanks much!

-Mike

Al Letellier_9

radiant leak

Mike, for your description, I'm not sure that you've proven there is a leak. Get a pro to isolate the radiant zone and pressure test just that part of the system before comdemning it...there may be a leak somewhere else or a faulty expansion tanks or even a faulty gauge....it pays to take the time to check things out very thoroughly before giving it the old "thumbs down"

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hr

Does it drop to zero?

If not, you may not have a leak? What type of tube and how old of a system?

I'd start with a new pressure gauge somewhere in the system and do some more checking. Most plumbing supply shops have lazy hand gauges that screw onto a hose bib, like a boiler drain Best to confirm if, and how much pressure you lose over a period of time.

hot rod

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Mike Clements

Thanks Al!

I will get the radiant part isolated and tested. I had a heating guy out today to get some prices. He also said the leak might be elsewhere, but more then likely, I'd see some water or water damage somewhere.

He also said something about I might be only losing a little pressure because the water isn't being heated, just circulated.

He also mentioned the bladder in the tank might have a leak. It had dropped to 2 lbs last winter.

He also pointed to some crusty valve on some pipe leading to or from the boiler that has the tank on it.

Thanks again,

Mike

Mike Clements

Thanks Rod!

The pressure had dropped to zero when the reducing valve clogged up. I think it was running like that for a whole heating season. I had heard water sloshing around in a few of the convectors all winter.

The house was built in 1964 and has copper tubing. The boiler is 32 years old.

I guess I'll have the radiant part isolated and tested to start with as Al suggested. I had some guys out last winter. They pressurized the system with some gas...maybe nitrogen. Then they walked around with some meter. Turns out that they didn't wait long enough for the gas to seep up through the concrete, plus, I have carpeting over the slab, so I don't know if they would have ever detected the leak w/o taking up the carpet.

Sounds like I have a leak somewhere simply from the fact that the reducing valve got clogged at least once. When it was discovered, the guy said it looks like someone monkeyed around with it in the past and he thinks it had previously clogged.

Thanks, Mike

hr

Gosh a 40 year old

copper radiant system It may be time to start thinking about a plan b. if more than one leak appears, you may be in for an uphill battle. Nothing lasts for ever.

hot rod

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Ed_13

Concrete Slab

I have a 45 year old concrete slab with copper piping. No leaks for the heating system but the domestic water pipes have failed long ago. (much higher pressure). I installed a small water meter on the boiler feed to check for leakage and long term seepage. So far no movement other than the first boiler fill. I do agree a slab 40 or so years is on borrowed time but I do love the radiant.