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Steam Heating in a REALLY big building in NYC

I am working on a 44 story office building across from city hall, built in 1924. I got the job because when we were standing on the 23rd floor, there was lots of banging noise.  So I asked the building engineer if the building is pulling a vacuum on the return side and he said that the vacuum system hasn't worked properly in years.  I also saw that a lot of the pipes at the ceiling of 23 are pitched poorly and that there is poor insulation.  When I told the owner about these issue, he called his plumber and the plumber repitched a lot of the piping and insulated the pipes and as a result, the banging was significantly reduced.  The owner then hired me to replace the vacuum return system.

The building used to have Con Ed steam but now works off of its own steam boilers.  Steam is sent express to the ceiling of 23 where it is fed up and down.  the steam traps at the ceiling of 23 are ancient and likely original.  The Watson McDaniel rep said that the traps are Webster heavy duty F&Ts, likely more than 30-40 years old.  See the attached picture.  So we have to replace these as well as replacing the traps in the rest of the building.  They are planning on replacing the traps in the entire top half of the building this summer. 

The plumber also came and put in some piping traps, just dips in the piping, at the ceiling of 23.  One of the reps also mentioned that we may have to create a false water line in the basement because the newer boilers have a water level that is about 2-3 feet lower than the old water level. 

I would appreciate any input/insight with regard to the steam system in the building.  Thank you guys for all your help. 


  • Pumpguy
    Pumpguy Member Posts: 627

    replacing a vacuum pump system in a building like this, the most important number to consider is the CFM of the vacuum pump. Don't just look at the EDR rating of the pump because many pump manufacturers will use different air capacity (CFM) vacuum pumps for the same EDR rating.  It is sooo easy to undersize the vacuum pump,  and when you do, the pump just runs continuous and never reaches the target shutoff point. 

    Also, as a general rule, liquid ring vacuum pumps are more efficient than venturi water jet type vacuum pumps, in terms of CFM/HP.  Also, water jet types may not be available with enough CFM  air capacity for this building. 

    Another thing is condensate temperature.  Vacuum pumps like (need actually) cold condensate.  The higher the vacuum you want, the colder the condensate needs to be. 

    I am not a boiler guy, but since you will have pumped condensate to feed the boiler, I would question the need for the false water line.

    I would be happy to discuss the pumping equipment needs of this building with you if you think I can help.  Call me anytime at 1-815 678 7734.

    Dennis Pataki

    Dennis Pataki. Former Service Manager and Heating Pump Product Manager for Nash Engineering Company. Phone: 1-888 853 9963
    Website: www.nashjenningspumps.com

    The first step in solving any problem is TO IDENTIFY THE PROBLEM.
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,487
    Nice job!

    You'll find those Webster traps in here. This is from the Library:

    Retired and loving it.
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