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Hello –
Related to my other thread on “Boiler Pressure Q”, how common is it for under slab pipes to corrode or deteriorate and develop leaks and cause a boiler/baseboard system to lose pressure ?
I have two runs of under slab piping, one from the boiler to a baseboard radiator about 15′ away.
Another run is between that radiator to another radiator about 10′ away.
These pipes date back to mid 1950’s.
There are no leaks apparent in any of the pipes that are visible, which are all copper.
Not sure if what’s under the slab is copper – could be galvanized pipe.
Thanks for your help.
Alan
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Well....therein lies the current radiant heating controversy. It used to be very common that after a few years galvanized in-slab piping developed leaks. Then along came the copper folks who said they had the problem whipped. But, lo and behold in a few more years their pipes developed leaks. Now, we have another wave of folks who say their materials won't leak.
So, since the pipe is already there all you can do is keep an eye on it with a plan on what to do when it starts to leak.
*Hi, Fred -Re - "after a few years galvanized in-slab piping developed leaks".Yikes. Being a mid-1950s era house, I guess this means it's possible the under slab pipe sections could have been leaking for a good number of years - it seems to be galvanized piping and it must have finally worked itself into a fairly fast leak. Fast enough for the system to lose pressure - from 12-lbs to zero - in about an hour.This solves all the mystery of our frequent problems with air in the system in the last two heating season, which was being blamed on the lack of modern air removel system - i.e. bladder tank/air separator/bleeder valve.And lately the system was requiring frequent topping off and bleeding, which I had initially thought was related to the recent draining of the system for some circulator repairs (no isolation valve...).As soon as possible I'm going to eliminate the under slab piping from the loop and splice in new copper lines above the floor.I would love to hear some more first hand experiences but none of this has been a turn-off for me against radiant or convective type heating system.Alan
*Yep, it sure seems that those old galvanized pipes have long ago given up the ghost. It also seems you are right on about your air in the system problems. When you get your convective hot water system installed your problems should be behind you.Maybe it is the conservatism of age; but I remain skeptical about radiant heaing in concrete floors. Each generation brings some new attempt at making it work; only to have a failure some years downstream. The problem isn't comfort. It is repairability when a leak develops, or when someone punches a hole in the tubing during a remodel or such.Now convective, hot water baseboard is another matter entirely. It is used extensively and reliably over much of the continent. In fact one builder I know even stubs in piping so when the radiant heat system fails the owners can easily switch to convective heat. I have never gone to that extreme but the example shows its' reputation for reliability and comfort.With today's tight houses the biggest downside to convective hot water heating is the need for a separate air exchange system. Without that it is near impossible to maintain a healthy indoor atmosphere. In your 50's house you most likely don't have that concern though.Good plumbing!
*Hi, FredJust to clarify my situation -I do have baseboard radiators.The suspect under-slab pipes are several short runs that connect some of the baseboard units in the basement.Anyway, just have to go for it and eliminiate them pipes....Not even going to bother digging into the concrete to investigate.
*b WBA At Your ServiceAlan, You don't need to jackhammer first, you can isolate these loops and pressure test for leaks.
*Hi, Tim -I did consider pressure testing for the leak but if the end result is going ahead and eliminating the under-slab pipes anyway why bother ?So far, everything I've heard about old under-slab pipings has not been good so it would be prudent (well, sortof after the fact now that there seems to be a leak) to go ahead and nip it in the bud.I'm fortunate it is very clear where the under-slab runs are (there are three different sections) and there are no leaks anywhere in any of the visible part of the heating plumbing lines.The leak may be at only one of the three sections but I should go ahead and get rid of the other two while I'm at it.One of the three may be a little tricky as I have to figure out where one end leads to after it goes into the slab - need to find where it reappears above slab, which is hidden somewhere in the wall of a bathroom and travels up into the main floor joists.Time to move things out of the way.Take care,Alan
*Howdy, folks -An update on the leaking under-slab piping....While following the baseboard radiator units around in the basement I found a section of under-slab piping that's already been eliminated from the run who knows when. I can see where they hacked off the pipe where it enters into the slab and soldered on a copper section to run along the baseboard to the next baseboard unit.Never paid attention to it before except maybe wondering why there is a exposed copper piping (painted).Whoops, I guess I'm suppose to say fin tube convectors, not radiators... ?
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Hello -
Related to my other thread on "Boiler Pressure Q", how common is it for under slab pipes to corrode or deteriorate and develop leaks and cause a boiler/baseboard system to lose pressure ?
I have two runs of under slab piping, one from the boiler to a baseboard radiator about 15' away.
Another run is between that radiator to another radiator about 10' away.
These pipes date back to mid 1950's.
There are no leaks apparent in any of the pipes that are visible, which are all copper.
Not sure if what's under the slab is copper - could be galvanized pipe.
Thanks for your help.
Alan