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OT- Nitrogen Bottle and Regulator

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  • OT- Nitrogen Bottle and Regulator

    I'm planning on replacing my heat pump this fall. Using nitrogen to flow while soldering, purging and pressure testing the lines is an accepted practice for r410a. Do I have to buy a filled bottle or can this be rented? And what about a regulator, does nitrogen take a special regulator?

    I know I bought the largest oxygen bottle available (ones that can readily be exchanged), I really don't need to buy a one time use bottle.

  • #2
    You could rent a cylinder but the smart money is to buy one.
    Nitrogen uses a CGA 580 connection. You will need a pressure regulator(as opposed to flow for welding) that has the correct delivery pressure range. A Western REB-7-5AC is what I have always sold.

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    • #3
      Buying or leasing / renting depends on your local supply store policy.

      No special regulator needed. I use the one from my argon cylinder when I have to use the nitrogen.

      JL..................

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      • #4
        The issue with using a flow gauge/meter is that you cannot control the pressure. It may not make a difference but I like to use the proper tool as long as it is feasible.

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        • #5
          I have a regulator for my MIG, thanks! Hopefully I can get enough pressure through it to test the lines once silfossed. All this will go through the manifold gauges so I'll know what the pressure is.

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          • #6
            Originally posted by BigMike782 View Post
            The issue with using a flow gauge/meter is that you cannot control the pressure. It may not make a difference but I like to use the proper tool as long as it is feasible.
            My flow meters have scales for 4 different types of gas. The cylinder pressure doesn't matter.
            My argon bottles are filled to about 2500 to 2700 psi. When the pressure gets down to 500 psi the flow meter still works. So pressure isn't a big issue.

            JL................

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            • #7
              Originally posted by JoeLee View Post
              Buying or leasing / renting depends on your local supply store policy.

              No special regulator needed. I use the one from my argon cylinder when I have to use the nitrogen.

              JL..................
              Yep. The gas house will require a deposit of $150 to $300.The cost of a new tank. Then you just swap out at the dock and pay only for the gas. When you are done with the bottle you get your deposit back. That way you do not need to keep your bottle certified. Also a lot of places do not fill their own bottles on site. They ship to a regional distribution center. Where every empty bottle is date and testing certified. Your personal bottle would need to go through this process and get shipped back to your branch store just for you. No gas shop will fill personal bottles around here.

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              • #8
                Originally posted by JoeLee View Post
                My flow meters have scales for 4 different types of gas. The cylinder pressure doesn't matter.
                My argon bottles are filled to about 2500 to 2700 psi. When the pressure gets down to 500 psi the flow meter still works. So pressure isn't a big issue.

                JL................
                What is the working pressure of your flow meter?
                Most likely 25psi. Like I said a flow gauge/meter may work but that's the same as saying I can use my drill press as a mill.

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                • #9
                  My flow meters are made by L Tech. I can't find any pressure rating on it but the gauge goes up to 4000 psi. so I'm sure the working pressure is within that. The first one was what the welding supply store gave me when I bought my first TIG machine. I liked it so I bought a couple extra ones for other cylinders. The sight glass / CFM gage is graduated for I think four different gasses and can be rotated.

                  JL.................

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                  • #10
                    As far as I know MIG Gas Flow Meter and Regulators will limit the pressure to a relatively low pressure (I've read that the regulators are generally set at 50psi but don't take that as gospel) for welding purposes but if testing the heat pump lines requires a higher or lower pressure than the MIG gas flow meter is able to provide then it likely will not work. MIG gas flow meters are calibrated for cubic feet per hour of gas flow at whatever pressure they are set at and aren't calibrated for output pressure. It's quite possible some are able to have the output pressure adjusted but since it's flow that is important for MIG welding and not pressure, it is likely they are preset to be safe for the average consumer to connect to all the different manufactures welders.
                    Location: Saskatoon, Saskatchewan, Canada

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                    • #11
                      25 psi is most common but there are some 50 psi.

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                      • #12
                        I have worked in the HVAC trade for many years. I use a pressure type regulator. For brazing the lines, I just crack the regulator adjustment open and listen with my ear to the hose for a very tiny flow. The idea is to purge the air out of the lines, if you develop any pressure it will blow the braze out of the joint and make a leak, you only need a very tiny flow.

                        For pressure testing, on R410a systems, I test at 300PSI. The evaporator coils are factory tested at 450psi normally. The high pressure shows up extremely tiny leaks, that the idea. The pressure is left on during the test for at least a hour.

                        Another important point, the OP mentioned soldering. The lines are supposed to be brazed, not soldered. Its done with 5-15% silver rod and acetylene, no flux. A propane torch is not nearly hot enough. R410a systems can hit well over 500pis under some circumstances.

                        Lastly, I might mention that the OP is doing a DIY install and thus the reason for not having the nitrogen setup. I hope he realizes he also needs a vacuum pump for the next step, a HVAC type deep vacuum pump (100 microns) not just any old vacuum pump. He may be intending to call in someone to evacuate (vacuum) the lines, charge the system, and start it up, in which case he will not need the pump.
                        Last edited by Sparky_NY; 08-04-2016, 10:37 PM.

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                        • #13
                          Sparky, thanks for your input. I agree and realize the lines need to be silver soldered, not just plain solder. I mentioned silflossed in another post. Yes, the nitrogen flows through the the lines, not building pressure. And of course the vacuum. Most all manufacturers recommend a vacuum to 500 microns, some may state 350. Using nitrogen to purge the air from the lines greatly improves the vacuuming process by removing normal air and moisture. It's not rocket science as most HVAC people want you to believe. Using the proper tools and procedures it's not a problem. I installed my 13 year old r22 and have not had an issue with the refrigeration part, only replaced the condesor fan in all those years. I will have a friend/tech to evacuate my old system before I start.

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                          • #14
                            Originally posted by rws View Post
                            Sparky, thanks for your input. I agree and realize the lines need to be silver soldered, not just plain solder. I mentioned silflossed in another post. Yes, the nitrogen flows through the the lines, not building pressure. And of course the vacuum. Most all manufacturers recommend a vacuum to 500 microns, some may state 350. Using nitrogen to purge the air from the lines greatly improves the vacuuming process by removing normal air and moisture. It's not rocket science as most HVAC people want you to believe. Using the proper tools and procedures it's not a problem. I installed my 13 year old r22 and have not had an issue with the refrigeration part, only replaced the condesor fan in all those years. I will have a friend/tech to evacuate my old system before I start.
                            Let me add that you do not need a very big tank of nitrogen. A 40 cuft tank (2 ft tall) is enough to do about 5 residential split system installations, pressure test and all. Locally, that tank costs well under $20 to refill. I am quite curious if It is a Goodman system you plan on installing?

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                            • #15
                              No, I think I'll get a Rheem. Goodman's are more a contractor grade unit from what I hear. Thanks for the tip on the bottle. I also don't need but less than a pound of r410a.

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