ASPE Open Forum

Expand all | Collapse all

Motorized Butterfly valve - Leakage during Pressure Testing

  • 1.  Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 12 days ago
    Hello everyone,

    Application : Chilled water system - Air conditioning

    We are facing difficulty with the closure of the valve completely (not closing completely) and this cause a leakage of water. The liner in the valve came out from its position and creating disturbance to the wafer disc to close.

    To avoid this issue on leakage, Installation team used companion joints (elastomer flanges) to get tightness and to avoid leakage. But, it fails.

    Now my questions are,
    1. Manufacturers are strictly advising not to use elastomer flanges. Why is to so?!
    2. How this issue can be resolved?!

    Thanks and Regards,
    Mohamed Faizal M, Application Engineer,
    Maven Trading & Installation WLL,
    Doha-Qatar
    mohamedfaizal421@gmail.com


  • 2.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 11 days ago
    Mohamed,
         What piping material was specified for the project?

    ------------------------------
    James Richardson
    Plumbing Inspection Supervisor
    City of Columbus
    ------------------------------



  • 3.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 10 days ago
    Hello James sir,

    The piping material is Black carbon steel

    Thanks

    ------------------------------
    Mohamed Faizal
    Application Engineer
    Maven Trading & Installation
    ------------------------------



  • 4.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 11 days ago
    How do the companion flanges fail? Is the leakage past the valve or out of the valve assembly? Why not use high-performance butterfly valves without elastomer flanges other than cost?

    ------------------------------
    Michael Divens CPD
    Senior Mechanical Designer
    PDC Inc. Engineers
    ------------------------------



  • 5.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 10 days ago
    Hello sir,

    Thanks for your kind response!

    Intially, there was a leakage outside the valve and then, they replaced the grooved flange to welded flange and this issue (leakage outside the valve) is resolved.

    Now, the leakage passing inside the valve above 6 bar pressure. Meaning, the valve is holding upto 6 bar pressure and above that, the minor leakage arises.

    what do you mean by high performance butterfly valve?!

    Note : The valve used can hold pressure upto 10 bar. This issue is only in few valves and this is giving confusion, whether there is a problem in the valve or some installation error

    Appreciate, if you can provide further inputs and advise!

    Thanks and Regards,
    Mohamed Faizal
    Application Engineer
    Maven Trading & Installation
    mohamedfaizal421@gmail.com

    ------------------------------
    Mohamed Faizal
    Application Engineer
    Maven Trading & Installation
    ------------------------------



  • 6.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 10 days ago
    I am assuming you are using lug style valves and not wafers.  I am not a fan of wafer style valves.  If these are larger valves which have bigger disks, then you need to be conscious of upstream and downstream components that may interfere with the operation of the valve or disruption to flow if there is a tee or elbow.  I am a proponent of high performance butterfly valves in hydronic systems.  It is not uncommon for butterfly valves with EPDM seats to have minor leaks after several years in service regardless of manufacturer.  Maintenance properly in clean water systems that are properly flushed, they seem to work good, but how many systems realistically get that kind of attention once in service.  Elastomeric seats can be damaged by dirty water systems or if they are not exercised or maintained routinely.  The shaft is centered on the disc with elastomeric seat which typically spins the disc and seal about the shaft which creates friction as it spins.  Double offset high performance butterfly valves have an offset disc and Teflon seat where the disc spins slightly off center and pushes into the Teflon seat when closed.  The Teflon seat is more resistant to abrasion and damage than elastomeric, but still could be damaged under extreme scenarios with dirty water systems with large particles.

    Refer to the Dezurik, Keystone, or Nibco websites for more information on high performance valves.  Keep in mind high performance butterfly valves have many material options and such.  For standard hydronic systems, exotic materials are not required which helps to keep the cost down.  Victaulic 300 Masterseal valve incorporates an offset disc with an EPDM seat which is a nice butterfly valve between a high performance and a standard resilient seat.

    ------------------------------
    Scott Jackson, PE
    Senior Mechanical Engineer
    RPA Engineering
    ------------------------------



  • 7.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 10 days ago
    Its centering lugs (wafer type)

    ------------------------------
    Mohamed Faizal
    Application Engineer
    Maven Trading & Installation
    ------------------------------



  • 8.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 10 days ago
    Your response is informative. I would request to advise some troubleshooting ideas, where i can resolve this issue!


    ------------------------------
    Mohamed Faizal
    Application Engineer
    Maven Trading & Installation
    ------------------------------



  • 9.  RE: Motorized Butterfly valve - Leakage during Pressure Testing

    Posted 10 days ago
    Mohamed, the high performance butterfly valves (HPBV) to not use elastomers for the valve seat surface but instead use metal-to-metal contact for a positive, durable seal. Elastomers may be affected by cold temperatures making them stiff and brittle or may not be suitable for glycol or other chemicals. I assume you have strainers in the system. These must be used as any debris or solids floating through the system can also have an effect on valve sealing performance.

    ------------------------------
    Michael Divens CPD
    Senior Mechanical Designer
    PDC Inc. Engineers
    ------------------------------