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Radiators

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Mpj
Mpj Member Posts: 109
Hello All,

I am removing a steam boiler and installing a new Alpine hot water boiler in its place. I am converting the existing steam radiators from single pipe to two pipe hot water, running PEX back to the boiler room and connecting to a manifold.

The existing radiators are tube and column type (the sections are connected together). My question is can I use the taps on one side top and bottom to connect to my new piping or do I need to install the pipes on opposite sides?

I ask this because some radiators are close to the walls and I can not get to the other side to connect. Any advise would be great.

Thanks

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  • Brad White
    Brad White Member Posts: 2,398
    edited October 2010
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    Firstly

    can we presume that you have insulated and sealed your house fairly well? That is often and usually but not absolutely the difference between a steam radiator output and the same with hot water, about 35-40% heat loss reduction. Also that your boiler size and re-use of radiators is founded in a calculated heat loss? A good place to start and I imagine you have crossed that off your list already.



    That said, there are fittings and valves made for use with PEX and other tubing that will even allow a single bottom bung to be used to feed a radiator. These work best with constant circulation and in fact, constant circulation works pretty well regardless.



    These valves have a supply-side injection nozzle which extends into the radiator some distance, away from the influence of the return suction. This enables the water to start internally circulating and gives fairly even radiator surface temperatures.



    (If you are an endoscopist, you will understand this principle well. If you are over 50 years of age with a reasonable medical plan, you will understand this almost as well. :)



    Stepping back from that, I have piped CI radiators across the bottom, in the bottom/out the top and in the top/out the bottom. Every which way except across the top. If there was a difference, it was absorbed in the margin between my heat loss calculations and the actual radiator output. In other words, I could not tell the difference and probably neither could you.



    My own house has a (formerly) gravity HW system with piping in the top and out the bottom on the same side on at least three of them on the second floor and the first floor has them all across the bottom to give an idea of what is said to work..



    This will be our first winter, but the house is 97 years old so if there are any complaints, most of them are dead now.  We shall see, but if experience dictates, it should work just fine.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"



    -Ernie White, my Dad
  • Rod
    Rod Posts: 2,067
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    Endoscope for Radiators

    Hi Mpj- Here's a link that may be of help to you.

               http://www.hydronicalternatives.com/Steam-to-hot-water-conversion-valve.pdf

               - Rod



    Brad- It's great to have you back! I really missed your humor and knowledge!

    "Endoscopist"....."Lady Gaga" ....."Heinz Guderian".....ROFLOL!
  • Brad White
    Brad White Member Posts: 2,398
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    That is the Valve, Rod!

    Hey Rod, thanks for finding that H-A brochure and posting it! I was trying to remember what brand I had seen. 



    Thanks for the kind words and encouragement.



    BTW, you know the medical definition of an endoscope, don't you?
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"



    -Ernie White, my Dad
  • Ironman
    Ironman Member Posts: 7,379
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    Make Sure

    You use Oxygen barrier PEX. This should go without being said, but many DIYs don't always know there's a difference.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Rod
    Rod Posts: 2,067
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    ?

    Brad-  I'm afraid to ask! 
  • Mpj
    Mpj Member Posts: 109
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    radiators

    Thanks for all your input. Hopefully it will all work out fine.
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