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Quick Air Vent Question

Sil
Sil Member Posts: 72
in Strictly Steam
Trying to learn all I can about my single pipe steam system. After 12 years of service I decided to refinish my rads and have had all sorts of surging and pipe banging issues (no good deed goes unpunished).



Today I decided to hunt around for a main vent. Several years ago I insulated all the pipes around the boiler and there were no vents in the piping around the boiler. I tried my best to follow the main line into the finished part of my basement and behind a wall.



Lo and behold in a really tight area behind the wall where the main has an elbow where the return must start its run... I could feel a vent. I had to rip out part of a window well... but I got the valve off (pictured below). Its an old Hoffman No 70 and had only 1/8" threads.



My question is, what should I replace it with?



Can I for the time being (like until the weekend) just put a Maid-O-Mist on there with the little cap taken off (the screw on cap that would make it a #4, 5 or 6)?



Thx



<img src="http://i203.photobucket.com/albums/aa262/silmarg/DSC_0117.jpg" width="1023" height="680" alt="" />

Comments

  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,577
    really small

    try as soon as possible to put on a proper main-line vent, like a gorton#2. that hoffman is only capacious enough for a radiator-not a main!--nbc
  • Dave in QCA
    Dave in QCA Member Posts: 1,788
    Main Vent

    Is there a bushing where you removed this 1/8" vent?  If so, take it out and follow Nicholas' advice.  If it is not a bushed fitting, then you have another problem.  It really should be replumbed so that you can install a proper "main" vent.  However, in the meantime, you could use a Heat timer varivalve vent in the wide open position. It will vent the same as a Hoffman #75. 
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Sil
    Sil Member Posts: 72
    no bushing

    The vent was tapped into the elbow at the end of the main (where it turns down into the return).  No Bushing.  Just and 1/8" tapping.

    I will have to find a heat-timer dealer in my area.

    Ugh... I keep finding more bad news...
  • Dave in QCA
    Dave in QCA Member Posts: 1,788
    try pex supply

    Try Pex Supply

    http://www.pexsupply.com/Varivalves-362000

    Make sure you get the angle style, as this is the configuration of the one you removed.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
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