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How much steam mains should be pitched?

NYwoman
NYwoman Member Posts: 26
Any advice on how much the steam mains should be pitched. Are all houses with air vents for steam mains? I cannot find where my house has the air vents.

Comments

  • KC_Jones
    KC_Jones Member Posts: 5,722
    It depends upon the type of main you have. For parallel flow mains (condensate and steam flow same direction) 1" per 20' is sufficient. For counterflow (condensate and steam flow in opposite directions) 1" in 10' is sufficient. More than those numbers is fine, but don't want to go less. You need to follow your main pipes until the end and you should find air vents. If you can't find them you might not have them OR they could be buried in a finished ceiling or something.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    NYwoman
  • NYwoman
    NYwoman Member Posts: 26
    How do I know if my system is parallel flow or counterflow?
  • KC_Jones
    KC_Jones Member Posts: 5,722
    If you have return pipes coming back from the end of the main into the boiler room you have parallel flow, if you don't have those pipes you have counterflow. What I can see in the pics you posted it appears as if you are parallel flow.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    NYwoman
  • NYwoman
    NYwoman Member Posts: 26
    I can only see one pipe coming back on the floor. I will try to open the ceiling and check on Saturday. Thank you!
  • NYwoman
    NYwoman Member Posts: 26
    Another question: If I cannot find vents for the mains should I add them? How? Where? Which ones?
  • BobC
    BobC Member Posts: 5,476
    We need more information. How many mains , what size pipe, and how long. The system probably had vents at some point and somebody removed them. The volume of air in each main determines the size of vent you need, in general you need one Gorton #2 for each 20ft of 2" steam main - bigger pipes need more venting. How long does it take for steam to travel from the boiler header to the end of each steam main? The faster you can get steam to the ends of the mains the more fuel you can save.

    Does the steam main start high and then drop slowly as it goes along (Parallel flow)? If it does their should be a place for a air vent towards the end after the last radiator takeoff. If the system has a return the vent may be where the return drops down.

    If the main starts low and goes up as it goes along (counterflow) the vent fitting should be towards the end after the last radiator takeoff.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • NYwoman
    NYwoman Member Posts: 26
    I still need to skim it on Saturday because I am waiting for the handyman to help with the skimmer. I ran the boiler today at .5 psi cut in and 1 psi cutoff. There was less banging the first time that it fired. No noise in the basement and some noise in the radiators. It took 15 minutes firing and then in 20 minutes restarted. The second time there was more noise in the basement like always and some noise in the second floor radiators. The vents did not leak water like they were doing before. In addition, the temperature in the first floor (70) and second floor (69) is almost the same, before there was a difference of 5 degrees (first- 70 and second 65). I am still planning to skim it and replace the supply valves in two of the radiators above the boiler in the second floor. I want to know what you all think about it.

    Thank you.

    PS I am reading The Lost Art of Steam Heating by Holohan.
  • Fred
    Fred Member Posts: 8,542
    I would still guess there is some water pooling in the area where you hear banging in the basement. You may have to remove a bit of the basement ceiling to check the pitch of the main. Maybe the handyman that is helping with the skim port can assist you with checking pipe pitch as well??