Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

What are these??

Options
Ross_24
Ross_24 Member Posts: 82
in THE MAIN WALL
These are on an old oil-fired, hydronic system. They have me stumped. What are they?

Seem to be something for expansion but they have coin vents on the end of the pig tail which makes me think air elimination.


Dan Foley

Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Options
    I think it is an early style of water hammer arrestor. The vent is not to let air out, but to let air in, which is compressible. The spring design, theoretically, will absorb any hydraulic shock caused by quick closing solenoid valves (dish washer, clothes washers ice machines, etc). They are normally connected to the potable water system,and not the closed loop hydronic system.

    ME

    There was an error rendering this rich post.

  • Ross_24
    Ross_24 Member Posts: 82
    Options
    Mark Eatherton said:

    I think it is an early style of water hammer arrestor. The vent is not to let air out, but to let air in, which is compressible. The spring design, theoretically, will absorb any hydraulic shock caused by quick closing solenoid valves (dish washer, clothes washers ice machines, etc). They are normally connected to the potable water system,and not the closed loop hydronic system.

    ME

    Thanks, Mark! It's very odd, because this is the second home lately where I've seen these on the hydronic system not the domestic.
  • ChrisJ
    ChrisJ Member Posts: 15,727
    Options
    Perhaps they are being used for thermal expansion instead of a single compression tank?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541
    Options
    Mark Eatherton said:

    I think it is an early style of water hammer arrestor. The vent is not to let air out, but to let air in, which is compressible. The spring design, theoretically, will absorb any hydraulic shock caused by quick closing solenoid valves (dish washer, clothes washers ice machines, etc). They are normally connected to the potable water system,and not the closed loop hydronic system.

    ME

    Correct, quite common around here. The vent is for draining them as they fill with water over time
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Options
    Ross said:

    Mark Eatherton said:

    I think it is an early style of water hammer arrestor. The vent is not to let air out, but to let air in, which is compressible. The spring design, theoretically, will absorb any hydraulic shock caused by quick closing solenoid valves (dish washer, clothes washers ice machines, etc). They are normally connected to the potable water system,and not the closed loop hydronic system.

    ME

    Thanks, Mark! It's very odd, because this is the second home lately where I've seen these on the hydronic system not the domestic.
    Strange Ross... Can't really see it doing any good on a hydronic system unless there was hammering, like when happens with Honeywell valves are installed backwards... The applications I've seen were domestic.

    ME

    There was an error rendering this rich post.

  • Ironman
    Ironman Member Posts: 7,376
    Options
    The remnants of Grandpa's still?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Options
    ChrisJ said:

    Perhaps they are being used for thermal expansion instead of a single compression tank?


    Now THAT would really mess with the PONPC. I've seen jobs that had two expansion tanks on it. One in the basement near the mechanical package and one in the attic. The pumps kept switching between positive and negative discharge. I eliminated the tank in the attic and pumps started working as they were supposed to, providing all positive pressure differential.

    I seriously doubt that these devices would react much with a slow pressure increase, as opposed to stoping mechanically induced water hammer.

    ME

    There was an error rendering this rich post.

  • ChrisJ
    ChrisJ Member Posts: 15,727
    Options
    Mark Eatherton said:

    ChrisJ said:

    Perhaps they are being used for thermal expansion instead of a single compression tank?


    Now THAT would really mess with the PONPC. I've seen jobs that had two expansion tanks on it. One in the basement near the mechanical package and one in the attic. The pumps kept switching between positive and negative discharge. I eliminated the tank in the attic and pumps started working as they were supposed to, providing all positive pressure differential.

    I seriously doubt that these devices would react much with a slow pressure increase, as opposed to stoping mechanically induced water hammer.

    ME
    Well, they do allow room to expand without pipes bursting, so I donno?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

Categories