Results 1 to 7 of 7

Thread: orifice sizing

  1. #1
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,319
    I thought orifice sizes for a/c and ht pumps were the drill size, but tech at work said that its not standard for all manufacturers. If its not the drill size stamped on there, where did they pull those numbers from?
    Col 3:23


    questions asked, answers received, ignorance abated

  2. #2
    Join Date
    Feb 2005
    Location
    Alabama
    Posts
    534
    If you're refering to "piston" size, yes they are standard from company to company. A #72 Trane piston is the same as a #72 Bryant piston. The number is thousanths of an inch. I.E. a #57 piston has an opening of 57/1000's of an inch.
    "If you can't fix it, don't break it."

  3. #3
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,319
    AH HA! I thought so. Didn't make much sense to invent your own system when its simpler to just use 1000s of an inch. Thanks. Now I'll have to look into orifice adjustment due to elevation and lineset sizing after reading some other posts lately.
    Col 3:23


    questions asked, answers received, ignorance abated

  4. #4
    Join Date
    Apr 2002
    Posts
    1,383
    <<If you're refering to "piston" size, yes they are standard from company to company. A #72 Trane piston is the same as a #72 Bryant piston. The number is thousanths of an inch. I.E. a #57 piston has an opening of 57/1000's of an inch.
    >>


    That applies to the size of the hole, but not the amount of gas that goes through the hole, which is also influenced by the aerodynamic design of the orifice.

    If you look at the formula for calculating the gas passed by an orifice, it has a "factor" which is the fudge factor for this aerodynamic design. And manufacturers usually wont give you their fudge factor, in my experience.

    So, if your really, really want the correct BTU input, you usually have to call a tech rep and have them calculate it for you. For that you need the elevation of the equipment, the BTU content of the gas and it's specific gravity, type of fuel gas, size of orifice, the "factor" and the manifold pressure.

    I'm probably still forgetting something.



    Seattle Pioneer

  5. #5
    Join Date
    Mar 2005
    Posts
    132

    trying to chat

    cant get site to let me do nutin

  6. #6

    Re: trying to chat

    Originally posted by jasond1011
    []cant get site to let me do nutin [/B]
    B_________________________________________________ _________Hang dude,try again.

  7. #7
    Join Date
    Feb 2005
    Location
    Alabama
    Posts
    534
    Sounds like you're talking about gas furnace orifices Seattle.
    I think billygoat wa stalking about "piston" sizes, in which case the design of each one is very similar. The openings are the same though, making it possible to match a Bryant condensor to a Trane or other air handler.
    "If you can't fix it, don't break it."

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event