Gas pressure for pool heater. ?

The gas meter was just replaced. The heater is the only device using this natural gas. Heater requires 11 inches wc. I tested and had 6 at my gas valve on the heater.  I understand that I have to bleed the air before the heater will fire, but wouldn’t the pressure be the same after the air is bled?

4 Answers

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  • 2 weeks ago
    Favorite Answer

    The pressure will be the same with air or natural gas. The pressure is being provided by the regulator and it adjusts to maintain its set pressure regardless of the fluid in the line. 

    One thing you have to be sure of at those low pressures is the instrument you are using to make the measurements. It is easy for dial type instruments to be out of calibration. Only a instrument that uses a clear tube and water will give you a true reading.

    • ricky
      Lv 7
      2 weeks agoReport

      Finally someone read my question. Gas company trying to tell me my pressure is too low, because air was in the line. 

  • 2 weeks ago

    You need to talk to the gas company and get some help getting this heater started. Where is your pressure regulator? You should have both a regulator and a meter, and they should be located together. That regulator is furnished by the company (its a standard pressure) and none of it is to be tampered with. So you have to bleed the air out of the line. You do that by turning on the gas until you smell gas coming out the burner. Then you power up the heater and turn it on. It should light. If your gas pressure is too low, you will have less fire. That is a supply problem that is not the regulator or meter. They can supply all the gas you need. Your incoming line could be a copper tubing line and it can be too small if it is too far downstream of the regulator. (say 3/8' x 200 feet long). The pressure is the same, gas, air or a combination. Purge it out until you can smell gas then seal it off.

    • ricky
      Lv 7
      2 weeks agoReport

      Until the desired 11 inches of water column is reached. But as a pool tech, I’m not authorized to do that. Oddly enough, if this was his home heat, I am authorized under my a/c lic. 

  • 2 weeks ago

    not true. air and gas are not compressable at same rates

    • ricky
      Lv 7
      2 weeks agoReport

      But maybe it’s different on Vulcan

  • John
    Lv 4
    2 weeks ago

    I have a High Pressure Boiler License and also Electrical. The gas pressure regulator is the most important part in any gas system excluding the gas valve. After the gas pressure regulator, gas pressure is measured in inches of water and three or four inches of water sounds right. Methane is odorless and colorless and why the gas company puts stink in it so you can smell it.

    • ricky
      Lv 7
      2 weeks agoReport

      If I have 6 inches wc ( wc stands for water column) if I bleed the air that was in the line when tested at 6 inches, will the pressure go up or down?

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