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Hartford loop mystery on a counter flow one pipe system with dry return

JoeyQ Member Posts: 17
I would like to ask a question about a contradiction I may have found in the 24 th edition of "THE LOST ART OF STEAM HEATING". (It's probably my misinterpretation, DAN knows more than anyone, but here goes)

Chap 5 pg65 speaks about piping a Hartford loop from a dry return. Question answered is you need the Hartford loop for dry return. Drop the close nipple below the water to form a water seal between the steam in the boiler, and the return condensate in the return. To prevent steam going to the return and preventing the flow of steam. Ok I accept this logic....

Now on chapter 7 pg 83 they speak of 4 typical ways to pipe the system

1)parallel flow 2)parallel flow/up feed system 3)parallel flow/down feed system 4) counter flow system which is found in small buildings.

It says about option 4 that the pitch needs to be 1 inch every 10 feet.

The boiler provides steam to the top of the main . Condensate flows through the equalizer to return to the boiler. It then states you need not use an equilizer because the A dimension is in the boiler room.

My question is why does the water level safety not matter with the counter flow set up. Doesn't that defeat the purpose of the Hartford loop in the first place ? Isn't it possible to have an automatic water feeder turn on to fill a boiler with a dangerously low water line that's connected to a counter flow system?


  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,398
    The purpose of the Hartford loop

    is to prevent a leak in the return from emptying the boiler. Since a dry return is almost entirely above the water line, there's nothing to prevent. It can only leak while condensate is flowing through it, which the Hartford loop can't prevent in either a wet or dry return.

    In a counterflow system, the dry return is just a drip from the main to the return leg, so there's not much left to worry about.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • JoeyQ
    JoeyQ Member Posts: 17
    Since the dry return is basically a drip

    Since the dry return is basically a drip for the main I understand

    1) the piping must not be horizontal, but a vertical path to the bottom of the boiler. As this would cause water hammering if condensate hits live steam.

    2) a leaking dry return close to the boiler may empty the boiler of water. It would be obvious leaking is taking place. If a wet return leaked it may not be as evident
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,398
    A leak in the dry return

    would be analogous to a leak in the equalizer, so a system with a dry return is less prone to developing a leak below the water line.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • j a_2
    j a_2 Member Posts: 1,796
    Manf Specs

    In theory maybe its not needed….However any and all writings stress the fact you go by the manf. specs….Any steam boiler I have ever installed gives you a piping schematic or refers you to i=b=a= standard practices…Dan has always said go by the manf. specs…I have yet to see a schematic by a manf. not using a hartford loop….on a steam boiler
  • JoeyQ
    JoeyQ Member Posts: 17

    Hello friend I have never seen manufacturers specs for a steam boiler(the piping arrangement they insist on) or anything for that matter. Would you be able to point me in the direction of finding these piping details expressed as the manufacturer wants. In my little world I only have" the lost art of steam heating "book. Many are simply drawings. I would love to compare reality with everything I have read.
  • Mark N
    Mark N Member Posts: 1,090
    edited January 2014
    Boiler piping

    Go to the manufactures website and look at the installation manuals. They all show the piping diagrams. I just looked at pg 18 on the install manual for the Weil-McLain EG steam boiler and its piping diagram for a counter flow system looks just like the diagram in TLAOSH. On pg 7 of install manual of Slant-Fin Galaxy it too shows the counter flow piping diagram to be the same as in TLAOSH.
  • Double D
    Double D Member Posts: 410
    Counter Flow Piping

    Piping diagrams of counter flow systems.