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NYC007 Member Posts: 15
Hello All,

I have a 1 Pipe Steam Heating in a 6 family Building in NYC. Coming off the Boiler,Off the Main Header is a "T" with a 1 1/2" piper that runs 3 Floors up in the Bathrooms. The pipe ends in the 3rd floor ceiling with an Air Vent attached to the Top.

Recently I took the entire pipe out because when they Installed it in 1949, the poor design of the pipe sticking 4" into the bathroom doorway was obnoxious.

I capped off where it came off the "T" -

Well, all sorts of problems started. The water in the boiler would fill way past the sight glass in excess of 10-16 gallons of water. Water Hammering all over the place. The first floor Radiators would throw out plenty of water from the air vents.

My question is why ? What was the purpose of this Riser ?

I now, reinstalled a 1 1/4" pipe back in and tight against the wall where it at least looks ok. I have no excess water filling the boiler now, so why would this issue occur ? No more water hammer

Question 2 : I want to balance some of the front to rear of the building. Can i Install a valve on the rear portion to slow up how fast it heats up ? If so, what kind of valve on a 2" pipe / Cast


  • Steamhead
    Steamhead Member Posts: 15,329
    The riser was there to heat the bathrooms. Not sure why removing it made the system misbehave like that, but who wants a cold bathroom?

    Front-to-back balance is almost always a main venting problem. Measure the length and diameter of your mains and tell us what vents are on the ends of each. We can tell you what you need.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    JUGHNE Member Posts: 9,750
    Was the 1 1/2" pipe the only heat for the bathrooms?
    When you replaced it did you put the vent back on the top of the riser pipe?

    If this was the only main vent for the system, you probably need more.

    It may be easier to speed up the front of the building by adding steam main vents to the end of that main.

    How about pictures of the end of steam mains where your main vents might/should be.