I own a house built circa 1960. It has three zone hot water heating. Most of the house has baseboard heating, but the family room has hot water radiant heating in a concrete slab. I recently replaced the boiler and the installer recommended putting in baseboard heating in the family room. His reasoning was that those systems inevitably fail. I did not do that for two reasons, the first being money and the second being that I really like the warm floor in that room.
My questions are;
Is such a system nearing the end of its useful life?
Has anybody here experienced such a failure? What exactly happens?
As far as the tubing is concerned, I am not really sure. Copper tubing is used elsewhere, but where the connections enter the wall of the basement, they are galvanized steel. I find it hard to believe that galvanized steel would be used in the slab, but I really don’t know.
Your system is past its design life. Due to the time of installation, it is unlikely that the builder put in an adequate insulating layer inder the slab. In all likelyhood, the pipes are corroded to the point of blockage. Repair means breaking up the slab, and reinstalling the pipes, then backfilling-extremely expensive and disruptive. I’d look for alternatives (baseboard FHW system), or if you live in a chaep electricity region, radiant leat under the floor.
if you still are getting heat the tubing isn’t blocked.
metal does corrode in concrete (though depends on the metal, its thickness and use). also depends on the system fluids. copper and steel will be different.
i am not a HVAC nor do i have metal tubing in floor.
Is there any kind of additive added to the fluid to prevent/reduce corrosion? If so, does it need to be replaced periodically? Or are you just asking for trouble at this point if you touch it at all?
Just yesterday on Ask This Old House they addressed this issue. They were demonstrating the ability to run a new epoxy drain pipe inside a homeowners old damaged drain pipe and afterwords Richard said they now have the technology to do this on pipes as small as a quarter inch by pushing an epoxy slug through the pipe which effectively paints the inside of the old pipe with a new epoxy pipe. He specifically mentioned old radiant heat inside of concrete slabs as one of the applications.
As for whether or not this is being used in the field yet, I’m not sure.
That is a major problem with home heating systems, no water treatment. I work in a high rise building and I test the water in the closed loop systems monthly to be sure they are up to proper levels of chemicals.
If you want to keep the radiant floor going it may be a good idea just to plan ahead for the eventual abandonment of that system. Just make sure now that work is being done that adding a baseboard heating system and cutting off that radiant system would be easily and quickly done. At the very least you it would seem wise to install a way to isolate the radiant system to shut it down if it were to fail while keeping the rest of the house warm.