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47 year old radiant system

realolman Member Posts: 513
My wife is getting transferred and we're gonna hafta move.

I looked at a house in the best neighborhood in town.

Ad said it had radiant heat. Turns out it's on a slab in Western Pennsylvania and has a couple loops of 3/4" black iron in the slab hooked to a Weil McClain 1960 gas boiler.... certainly not what I expected. I was thinking a Munchkin or something like that.

Anyone have any thoughts on a radiant system that was installed in 1960.


  • kevin coppinger_4
    kevin coppinger_4 Member Posts: 2,124
    could be...

    on its last legs or you could be fine for 20 more years....I have replaced boilers that were attched to these systems that others were ready to abandon them...I isolated the one bad loop and left the system two years ago...no problems.
    I suppose it would really depend on how they set up the system? Steel would be better than the copper.Is there any insulation? kpc

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  • Dave Yates (GrandPAH)_1
    My firm

    installed a large number of similar systems in the 1940's and we continue to service them today. Black iron and concrete have very similar coeficients of thermal expansion & all of our local 1940's-era copper-in-crete systems would tend to support the notion that BI works best as almost all of the copper systems have failed.

    We've installed new boilers on a number of the old BI radiant systems, although we have upgraded the mixing strategies.

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  • Ken_40
    Ken_40 Member Posts: 1,320
    One of the \"issues\"...

    with a 40-year old system is whether or not it is setup to "pump away."

    If it is setup with pumping away, there is a high probability the air in the system has been minimal and the longevity of steel piping has been saved from corrosion.

    If however the system is pumped so as to have the water sucked thru the piping, the proability of air contamination is much greater - and the system condition may be seriously compromised as a result.

    A hydrostatic test and near boiler piping examination should reveal system leaks and levels of corrosion in the radiant piping. If the system was tight for 40 years, you can get another 40 out of it.

    In all liklihood,

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  • hr
    hr Member Posts: 6,106
    As long as the pipe stays dry

    I've reworked a number of old leaky steel pipe systems.

    All the failures were caused by the pipe rusting through from the outside in.

    In one case the drum trap under the tub leaked and kept the ground wet enough to rust the bottom of the pipe out.

    It's real hard to determine the condition of those older systems or predict a life span.

    The systems that I have cut open show the pipe to be in excellent condition if it is completely encased in the slab.

    Often they were not zoned well, and tended to have wide spacing and ran pretty high supply temperatures to overcome the wide spacing.

    As Dave mentioned it may be possible to lower the temperatures or use outdoor reset controls.

    I'd still have a plan B in place should it ever leak ;)Possibly radiant ceiling, an overpour, or a dry system retro fit method, like the Viega, Watts Radiant Roth and others.

    hot rod

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