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  1. #14
    Join Date
    Jan 2005
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    2 psi systems are a rareity in our part of the country as well but are utilized in certain applications.Our residential meters have maop of 5psig as well. Most or our PFM sets are used in rural applications and vary in pressure 2psig, 5psig, 10psig, and 15psig. We are not installing any 5 or 10 PFM systems any longer sticking wtih either 2psi or 15 psi with loads up to 750cfh any requirements above that load we go to a pressure set which utilizes a meter & instrument.

  2. #15
    Join Date
    Jun 2004
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    Originally posted by jo8243
    Thanks for your reply. Could you go into a little more detail on the w.c. differential? What causes the w.c. diff to be 0.5" vs 2" and how do you make it 2" so it can supply up to 900 cfh?

    I do have a regulator upstream of the meter if that matters.

    I'm not a meter person myself, but what little understanding of pressure drops I do have, there is no adjustment, per se, of the w.c. differential (pressure drop) of a meter. I would surmise that pressure drop is governed by a multitude of factors, such as temperatures, mechanical condition of the meter, the volume of gas flowing at any given moment, the pressure being supplied to the regulator, and the mechanical condition of the regulator. All of these variables will ultimately dtermine the w.c. differential, (pressure drop) at the meter.

    I believe what is critical, is: 'What is the inlet gas pressure at each gas appliance, and is that pressure within the parameters listed on the appliance'? If these pressures exceed the maximum allowable pressure, damage to the equipment and or possible explosion could result. (Ugly!) If the inlet pressure is below minimum, the affected appliance will not deliver its' rated input (BTUH), and also possibly cease to fire at all. Gas pressures are not to be experimented with, if in doubt about your volume/pressure relationship, have your gas fired equipment pressures checked by a qualified heating contractor. More than likely, you will discover all is well with your needs being satisfied.

    If volume of gas being delivered to your appliances concerns you, have your heating contractor increase the size of the gas lines. I believe this is the safest approach of controlling quantity of gas delivered vs. increasing its pressure.

    If you are interested in pressures and such, pick yourself up any book that covers Boyles Laws, you will find in-depth reading regarding pressures.

    [Edited by re2ell on 02-22-2006 at 03:15 AM]

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