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Natural Gas and Propane orifice

BillBill Member Posts: 34
What is the opening measurement for a Natural
gas and propane fitting.


  • Not sure what you are asking

    please be more specific.

    There are a number of things to consider:

    Btu content


    Specific gravity and so forth. Give me more and I will answer your question.
  • BillBill Member Posts: 34

    Tim, That would be on a propane range or a natural gas range.

    You can clock a gas meter, but how do you clock a propane device. Must you use a manometer
  • Jim DavisJim Davis Member Posts: 305
    Burner orifice

    Natural gas orifices are larger for the same BTU as LP.
    A #40 orifice @ 3.5" W.C. = 24,440 BTU. The same orifice used on LP @ 11"W.C. would give you 67.100 BTU. Unfortunately the BTU's of the gas is always a guess at best.
  • Natural /LP Gas

    First most ranges today have coaxial orifices they are screwed all the way down for LP and all the way out for natural. They also have convertible regulators that you simply reverse the cap and convert the regulator. Most of them are marked. Watch out for infrared broilers they do not have coaxial spuds but there is a spud under a little metal plate in the top of the range which is a fixed orifice for converting. The oven heat control also has a little screw for converting the pilot it says Nat-Off-LP on it.

    As for the problem of not being able to clock on LP you are correct so here is what you do.Yes go ahead and take a pressure with the manometer to make sure what you have. If you have equipment set for natural and you want to convert to LP measure the orifices as to drill size, find out what the rating plate called for as to pressure. Most ranges today are 5" WC to 6" WC for natural. Then also from rating plate find out what the BTU's for top burner or oven and broiler make sure that matches up for what is on the equipment. You can now take that same info to an LP chart and for 10" WC determine at 1.52 specific gravity the correct orifice size for each burner. If the equipment is on LP and you want to check it just do the same with the existing orifices and the chart.

    At this point if you do not have coaxial orifices (they only come on ranges)you can do one of the following:

    1. Order new orifices

    2. Fill existing natural gas orifices with solder and redrill them, always drill from the back.

    3. Or the old gas mans trick (we did not carry torches) pean over the oriifce with a ball pean hammer and redrill.

    I have a guide available from our catalog that has all the charts and tables including the procedure for converting.

    The rule on sizing orifices is okay to slightly under gas but never over gas.
  • Charts & tables list

    for natural gas BTU Content of 1,000 BTU's per cubic foot is close enough or call the local utility as to what they use. Here in Rhode Island it is 1050 BTU's per cubic foot.

    For propane gas most of the time it is listed as 2550 at 1.52 Sp gr.

    For butane 3200 at 1.95 Sp gr

    It does vary daily but usually not to any point that would
    be unsafe.
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