This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.
This Website Uses Cookies
By closing this message or continuing to use our site, you agree to our cookie policy. Learn More
This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • Home
  • Products
  • News
  • Glitch & Fix
  • Hydronics
  • Radiant
    • Radiant Comfort Report
  • Blogs/Columns
    • R&H On The Road
    • John Siegenthaler
    • Dan Holohan
    • Ray Wohlfarth
    • Mark Eatherton: Radiant Know-How
  • Buyers Guide
  • Resources
    • Radiant Comfort Report Digital
    • Rep Locator
    • Industry Calendar
    • Store
    • Market Research
    • eNewsletters
  • Plumbing & Mechanical
Home » Converting A Two-Pipe Steam System
The Glitch & The FixRadiant & Hydronics

Converting A Two-Pipe Steam System

July 19, 2010
John Siegenthaler, P.E.
Reprints
No Comments


The Glitch

Overview: An old New England home has been heated with a two-pipe steam system serving plenty of sturdy cast-iron radiators. As part of an extensive renovation and insulation upgrade, the owner decides to upgrade the heat and convert the system to a high-efficiency, gas-fired condensing boiler. The piping system installed by the local plumber is shown below. It leaves as much of the two-pipe distribution in place as possible.  

Exercise: What are some design details that you think are incorrect or missing?

The Fix

Over decades of use, lots of “mud” can build up in a steam heating system with cast-iron radiators. It’s really a shame to push that mud into new portions of the system, and especially into the compact heat exchanger of the new boiler. I’d recommend a high-quality dirt separator on the receiving end of the flowing mud, and installed at a low point in the piping whenever possible.  

Be sure to leave room for a blow-down valve at the bottom because you are sure to be using it. Also be sure the flow velocity into the dirt separator is at or less than 4 feet per second. A hydraulic separator could also be used in place of the closely spaced tees, air separator and dirt separator.  

Another problem is the arrangement of the circulator in the boiler loop. It should be pumping into the condensing boiler (because the latter has a high-flow-resistance heat exchanger).   

Other details that are incorrect:   

  • If you expect hydraulic separation between circuits, do not install closely spaced tees as shown in the Glitch drawing. Instead, provide a minimum of 6 pipe diameter of straight pipe both upstream and downstream of the closely spaced tees.  
  • There should always be a good microbubble air separator on the outlet of the boiler.  
  • In the Glitch drawing, the circulator is at the low point of the distribution system - the most probable location for sediment to collect.  
  • Install an air vent on each radiator.


  • Links

    • The Glitch & The Fix - July 2010

    pm-subscribe

    Recent Articles by John Siegenthaler, P.E.

    Modern Hydronics Done Right Volume 5

    John Siegenthaler: New in the neighborhood

    The Glitch and Fix: Keep the cost down

    Single coil solution

    John Siegenthaler: Low temperature leverage

    Siegenthaler

    John Siegenthaler, P.E., is a consulting engineer and principal of Appropriate Designs in Holland Patent, N.Y. His latest textbook “Heating With Renewable Energy,” will be released in January 2016 from Cengage Publishing. It shows how to use modern hydronics technology to create systems supplied by solar thermal, heat pump and biomass heat sources. Additional information is available at www.hydronicpros.com.

    Related Articles

    Following instructions for installing a two-zone system

    Piping a dual-heat system

    Supplying two loads for multiple boiler system

    A primary concern in a multiboiler system

    Related Products

    Greening Steam: How to Bring 19th-Century Heating Systems into the 21st Century (and save lots of green!)

    A Pocketful of Steam Problems (with solutions!)

    Piping Systems Manual

    Facility Piping Systems Handbook, 3rd Ed.

    Related Directories

    ComfortPro Systems

    You must login or register in order to post a comment.

    Report Abusive Comment

    RCR logo

    RCR Buyers Guide

    Plumbing and Mechanical

    Plumbing & Mechanical December 2019

    2019 December

    Check out the December 2019 edition of Plumbing & Mechanical: 2020 B.I.G. Book, John Siegenthaler on geothermal water-to-water heat pump system design and installation, maximizing efficiency on small-diameter piping projects and much more!
    View More Create Account
    • Resources
      • Reprints
      • List Rental
      • Contact Us
      • AEC Store
      • Blogs
      • Radiant & Hydronics
      • Industry Links
      • Market Research
      • Custom Content & Marketing Services
      • Privacy Policy
    • Want More
      • Connect
      • Survey And Sample
    • Plumbing Group
      • PM Engineer
      • Supply House Times
    • Advertise
      • Advertise
      • Plan for 2020!

    Copyright ©2019. All Rights Reserved BNP Media.

    Design, CMS, Hosting & Web Development :: ePublishing