Results 1 to 7 of 7
  1. #1
    Join Date
    Sep 2008
    Location
    England
    Posts
    7
    Rep Power
    0

    How much OFN...?



    Hi all,

    Given the current climate (financial..), i've been asked to carry out the fitting of new PRV's to a couple of chillers. Whilst i have no problem undertaking the work, my main background is on the commercial side. The chiller has 2 circuits with 87/80kg of gas. The only problem i do have is estimating the ammount of OFN that would be required to pressure test the system.

    Would anyone know an appoximate figure of OFN required to pressure test a circuit containing 87kg..?

    With thanks,

    KD



  2. #2
    Join Date
    Sep 2007
    Location
    Somerset
    Age
    69
    Posts
    4,758
    Rep Power
    46

    Re: How much OFN...?

    KD.
    What are you proposing to do to the PRV's.
    You state pressure test, surely you mean leak test your joint onto the system?
    It is not a requirement to actually lift a newly fitted PRV.
    In fact doing so may well cause that prv to fail.

    If I am reading you wrong and you are wondering how much to leak check.

    I would try and isolate the High side to reduce the amount required. because on a chiller that size you would logically need at least a large size K or W (BOC sizes).
    Grizzly
    Last edited by Grizzly; 02-06-2012 at 12:55 AM.

  3. #3
    Join Date
    Sep 2008
    Location
    England
    Posts
    7
    Rep Power
    0

    Re: How much OFN...?

    Grizzly,

    Thanks for your reply. Yes, sorry, I meant leak-test.

    Just looking for a ballpark figure for an estimated amount of OFN to undertake the leaktest. As I have 2 chillers (four circuits) to fit new PRV's too. As part of the written scheme for the chiller, we are required to change the low-side PRV also. Point taken and already considered about isolating the high-side.

    My background is mainly light to medium commercial so a small 10L OFN normall does me just fine.

    For general interest the manufacturer (York) quoted £6,700 to fit new certified valves which were a further £800. Nice work if you can get it....

  4. #4
    Join Date
    Sep 2007
    Location
    Somerset
    Age
    69
    Posts
    4,758
    Rep Power
    46

    Re: How much OFN...?

    I am always surprised as to what differing Insurance surveyors expect, especially as they apply pressure regs to all prv's on chillers.
    When some are fitted to comply with en378.
    As a rule lp does not require changing.
    In fact if it's worth questioning upon what basis the lp side is being changed.
    Some written schemes as I say are applied incorrectly.
    Grizzly

  5. #5
    Join Date
    Apr 2007
    Location
    england
    Age
    36
    Posts
    372
    Rep Power
    22

    Re: How much OFN...?

    Hard to say how much, if in doubt give them an open price if quoting and be honest...tell them you cant estimate!

    I normally just go on experience for a rough guide, and if in doubt i ask at a local supplier..climate etc if i can bring some of the cylinders back if i dont need them. Normally if your nice they can be ok with it.

    Jay

  6. #6
    Join Date
    Jun 2009
    Location
    North East England
    Age
    41
    Posts
    714
    Rep Power
    19

    Re: How much OFN...?

    2 W size bottles from Boc should be ample remember to check the MWP Of the evap and stay 2 bar below (per circuit)

  7. #7
    Join Date
    Dec 2011
    Location
    Ireland
    Posts
    44
    Rep Power
    0

    Re: How much OFN...?

    I usually use a big bottle(size N I think) per system, should be plenty...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •