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Poor mans one pipe system

Wayco Wayne_2
Wayco Wayne_2 Member Posts: 2,479
I got a call to check the radiator heat in an old house down in DC. I had installed a kitchen radiant floor 7 years ago and the lady who was the home owner loved it a lot. However in the rest of the house she was having heating problems. Some of the cast iron radiators were not heating up properly. Someone besides me had piped the radiators, but right after they were done, she had  she left town for 6 years to live in France. (sweet!) She rented out her house in that time period and had never noticed the problem with the radiators. This is her first Winter back and she noticed it just wasnt right. As I stumbled around the clutter filled basement It was hard to figure out the piping. A lot of it was covered up with air conditioning ducts installed after the radiator piping and the piping was covered up. When I could see it it didn't make sense. It was copper piping leaving the boiler at 1 inch id copper. Down the run I could see 3/4 inch branches reducing down to 1/2 inch copper and then after a couple of tees to a nearby radiator it would enlarge to 3/4 in copper again. It eventually dawned on me that someone had installed a one pipe system, and instead of using mono-flo tees they had reducing couplings making the resistance that a mono flo normally would. It was kinda clever but it didnt work very well. The big old cast iron radiators, originally from a gravity boiler system, gobbled up the heat really fast and by the end of the run the water was no longer hot enough. There was no good way to balance the system between the different sized radiators. Some where small and some humongous. What a nightmare. I might recommend replacing it all with a radiant floor manifold with pex runs to each radiator, so there can be hot water to each radiator supply, and some balancing could be done if need be. Just when you think you've seen it all you see something new.


  • Charlie from wmass
    Charlie from wmass Member Posts: 4,314
    Had an old timer

    From the isle of long who would brag about installing systems like that. He would also make his own mono flow tees with soft copper and a flaring tool. The system could be separated into a couple zones if the budget is tight to get less btu's going through the 3/4".

    I am surprised they did not just install a larger circ. You could also do the reverse flow trick and constant circulation.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Wayco Wayne_2
    Wayco Wayne_2 Member Posts: 2,479

    What do you mean by the reverse flow trick? Thanks
  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,557

    I think he means you set it up so it pumps through in one direction, then reverses and flows the other way. Never saw it but heard about it. They do it with radiant when the loops are too long, I think.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Cheap fix...

    Grab some new Channel Lock water pump pliers, a head mounted flash light, and some grubby coveralls, and most importantly, a keen sense of calibrated crush, and crawl through the crawl space and grab the pipe between the tees and give it a squeeze. Not too much, just enough to cause more flow through the side branch. It's hard to undo crush. :-)

    (Of course, I am just kidding).

    As Charlie said, you could place a 4 way valve, piped like a cross, and reverse the flow through that circuit every 5 minutes or so. Or, go your route and pipe them individually with PEX and TRV's for independent control.

    I actually built my own venturi tees using Nibco drop in venturi inserts. In a pich, I have also taken a fitting reducing coupling and cut off the excess fitting part and dropped it into a tee and held in place by the pipe, soldered it in place and viola, venturi tee.

    The power of the venturi is absolutely amazing. Misunderstood, but amazing.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • EddieG
    EddieG Member Posts: 150

    Hey Wayne, how ya been? Been a while since I've seen you. It's Eddie, from down here in the sticks (Southern MD) I have done the 4 way valve trick on a radiant job where they had roughed in ONE 3/4 pex loop for an entire basement and wondered why it wouldn't work! Actually worked out nice and still works as far as I know. Well hope all is well with you buddy, stay in touch!
  • Wayco Wayne_2
    Wayco Wayne_2 Member Posts: 2,479
    Hey Eddie

    good to hear from you. I ve heard you keep elite company these days. It's good to know you're keeping the quality high in Southern MD. ;) WW
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