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Waterlogged compression tank

Andrew Siegmund
Andrew Siegmund Member Posts: 3
in THE MAIN WALL
> are you sure these tanks are just compresion <BR>
> tanks? i just replaced a pair of expansion <BR>
> tanks -they were ASME tanks with a bladder <BR>
> -these were Amtrol AX80 the older style tanks <BR>
> will have piping connected on 1 side --and a <BR>
> steel pipe plug --which covers the air valve <BR>
> ---------on the end ---- <BR>
<BR>
No diaphram, checked the drawings late last week.

Comments

  • Andrew Siegmund
    Andrew Siegmund Member Posts: 3
    Waterlogged compression tank

    How long would it take for a compression tank to become waterlogged if there was not an air/water separator in the system. If more details are needed let me know. Thanks
  • John@Reliable_13
    John@Reliable_13 Member Posts: 34
    Kind of like how many licks does it take.................

    to the center of a toostie pop. Some systems may need draining yearly, while the house next door hasn't been maintain for years and still going strong.
  • Uni R_3
    Uni R_3 Member Posts: 299
    Auto Air Vents

    Any auto air vents? They'll help speed things up.
  • [Deleted User]
    [Deleted User] Posts: 503
    Compression tanks and automatic air vents DO NOT MIX...

    And I presume that's what Uni R was trying to say, but in case it was misinterpreted, allow me to clarify. If you have the old ceiling hung expansion/compression tank, you can NOT have ANY automatic air vents ANYWHERE in the system.

    Converesely, if you have a diaphragmatic type of expansion tank you MUST have automatic air eliminator/vents.

    Confusing, sure. But if you follow these basic rules, and the rules of pumping away, your life WILL be much simpler.

    Carry on...

    ME
  • william_5
    william_5 Member Posts: 62
    water logged

    did you drain the tank all the way down ? with knowing where you live but around here you will get any where from 5 to 15 gal of water. is the feed vale by passing? do you have a coil on the boiler for hot water? you could have a hole in the coil.
    william
  • Plumdog_2
    Plumdog_2 Member Posts: 870


    Diaphragmatic? I like it.
  • Uni R_3
    Uni R_3 Member Posts: 299
    Sorry Mark

    If it wasn't clear enough for you Mark, then yes I was saying that auto air vents will decrease the time it takes for an expansion tank to become waterlogged. It will evacuate any air that goes into solution from the tank's large internal surface area where the air and water aren't divided.
  • Andrew Siegmund
    Andrew Siegmund Member Posts: 3
    some clarification

    The entire system is 3200 gal. There are two plain steel (no diaphram) 75 gal tanks. It's a HVAC system with two 500 ton Carrier chillers. The system usually has only one chiller operating, but the system is cross connected so the water in the cooling coils does not heat up too much. When the system is operating the water only passes through the operating side's air water seperator. Therefore any air that is "seperated" goes into the operating side's compression tank. Therefore the other side could become waterlogged if the system ran off the same chiller for an extended period of time.
  • oil-2-4-6-gas
    oil-2-4-6-gas Member Posts: 641



    are you sure these tanks are just compresion tanks? i just replaced a pair of expansion tanks -they were ASME tanks with a bladder -these were Amtrol AX80 the older style tanks will have piping connected on 1 side --and a steel pipe plug --which covers the air valve ---------on the end ----
  • [Deleted User]
    [Deleted User] Posts: 503
    Got it..

    We're on the same track, headed in the same direction :-)

    ME
  • [Deleted User]
    [Deleted User] Posts: 503
    Generally speaking...

    If the two tanks were properly sized, and only one tank was "on line" then you should have ended up with a LOT of free air roaming around the system.

    Normally, the tanks will be about 1/2 air and 1/2 water, and the air and water will be under pressure, the same prssure required to keep the water raised to the highest point in the system.

    As far as how long it would take to water log the tank, as with any hydronic question, there is only one correct answer, "It Depends..."

    I have worked on large systems like yours where they used bottled nitrogen to maintain the cushion on the expansion tanks.

    Are you experiencing water logging and consequential pressure changes within the system?

    Do you have one tank for the chilled water distribution system and one for the heating water distributuion systems, or is there just seperate expansion tanks at the individual heat/chill sources?

    Sounds like a 4 pipe system...is it?

    ME
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