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Vacuum Tank Question - How Long?

Mike_Sheppard
Mike_Sheppard Member Posts: 696
in THE MAIN WALL
Good afternoon everyone!

I have a quick question. I play with a lot of old steam systems around DC but very seldomly do they have vacuum pump systems. We installed a new large vacuum tank for a customer in DC this summer. Fixed a bunch of traps etc. Started the tank up for the first time today and after 20 minutes it still hadn’t started to pull a vacuum yet. It is blowing air out of the hurling chamber vent like crazy so it is definitely pulling air. Everything in the boiler room is tight. There are two small remote condensate receiver tanks out in the building and I verified the vent lines on those have check valves and are not sucking air in. The maintenance coordinator was off today so I was not able to ask if they had anything else open in the system at the moment.

So my question is - how long should it take under normal operating conditions to start pulling a vacuum on the system? With the system cold and all the traps open I imagine it could take quite a while.
Never stop learning.

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,488
    Sounds like something is open or broken somewhere. May have to fire the boilers and put steam to it to find out. You should see some vacuum fairly quickly.

    Do the condensate tanks have an overflow pipe where air can get in? any valves you can close to isolate parts of the system to make it easier to track down.

    Never really thought about how long it will take to get a vacuum. Cfm of the air in the system, pump capacity would need to be calculated.
  • Steamhead
    Steamhead Member Posts: 17,387
    Is there a vacuum breaker on the boiler?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Mike_Sheppard
    Mike_Sheppard Member Posts: 696
    edited September 2023
    No vacuum breaker on the boilers. All vents on the boilers closed (8,000,000 btu each, watertube boilers). There are two remote condensate receivers and I made air their vents had check valves on them and were not sucking air in.

    nothing in the boiler room is taking in air so it has to be something in the system. The engineer was off today so I couldn’t ask, but they probably have something in the system open that was sucking air. I hope…. Lol

    The vacuum pumps are 5hp each. They were moving some serious air. 
    Never stop learning.
    Mad Dog_2
  • ratio
    ratio Member Posts: 3,791
    Lets as the expert. @Pumpguy?
  • jumper
    jumper Member Posts: 2,385
    Try putting ice in reservoir of generator.
  • Mike_Sheppard
    Mike_Sheppard Member Posts: 696
    Update - someone in the building had their radiators removed and valves open.

    It is a condo building so people do whatever they want with the radiators in their units....
    Never stop learning.
    ttekushan_3
  • jumper
    jumper Member Posts: 2,385
    Mike_Sheppard said:

    Update - someone in the building had their radiators removed and valves open.

    It is a condo building so people do whatever they want with the radiators in their units....

    Often there is anarchy in condo buildings. Especially bulk metered ones.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,488
    edited September 2023
    Gee, I wonder where the air was coming from. LOL
    reggi
  • Pumpguy
    Pumpguy Member Posts: 698
    @Mike_Sheppard, sounds like you found the problem.

    How does the system work once the air leaks were plugged?
    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.

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