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  • Where did the refrigerent go?

    I replaced at work our 3 ton rheem package heat pump about 4 months ago due to some electrical problems. I had it sitting in the yard so I could turn it into a trainer model for the guys. Yesterday, tried to recover refrigerant and it was bone dry. I couldn't pull an oz out of it. There's no signs of any leaks anywhere and it's in a place where no one could tamper with it. I put a leak detector on it also. Today I charged it with nitrogen at 150 lbs and left it overnight but it looks like the pressure will hold. Any ideas what happened to the refrigerent? I know the oil will hold some refrigerant but 6 lbs of refrigerant?
    Buy cheap, buy twice.

  • #2
    Re: Where did the refrigerent go?

    Dont try to fool us Junkie. We know you recovered it and sold it.

    I usually leak test around 400psi with nitrogen. In fact I need a new regulator cause the threads are stripped out on mine from cranking the pressure up so high.

    I charged an old old a/c earlier this year. I swear there wasnt a drop in this thing. The owner said it had been working just fine up until a couple days earlier. I said if thats the case, I'll be seeing you again in a few days for a new unit. I talked to the guy a couple weeks ago and he said it had been running great all summer. I'm a little confused on that one too. Now that I think about it, it was an old Rheem too.

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    • #3
      Re: Where did the refrigerent go?

      Originally posted by gear junkie View Post
      I replaced at work our 3 ton rheem package heat pump about 4 months ago due to some electrical problems. I had it sitting in the yard so I could turn it into a trainer model for the guys. Yesterday, tried to recover refrigerant and it was bone dry. I couldn't pull an oz out of it. There's no signs of any leaks anywhere and it's in a place where no one could tamper with it. I put a leak detector on it also. Today I charged it with nitrogen at 150 lbs and left it overnight but it looks like the pressure will hold. Any ideas what happened to the refrigerent? I know the oil will hold some refrigerant but 6 lbs of refrigerant?
      were the service caps in good shape and tight? often times when people pull units they either don't replace caps or tighten them back up, schrader valves love to leak, or it could just be a real small leak somewhere else.
      Last edited by BILLG; 09-27-2007, 10:20 PM.

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      • #4
        Re: Where did the refrigerent go?

        I put new ones in just to make sure. No leaks. I put some r-22 in with the nitrogen and put some visqueen over the unit and stuck my leak detector underneath after a couple hours, no leaks.
        Last edited by gear junkie; 09-28-2007, 11:34 AM.
        Buy cheap, buy twice.

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        • #5
          Re: Where did the refrigerant go?

          something blocking the valve and not letting any thing out? thus appearing to be empty? (not accusing you, jsut a possibility) but did some "brain fart" occur and did not open up the correct valve.

          could temperature (contraction and expansion) be creating some form of a intermittent leak?

          ~~~~~~~~~~

          one if it was full, or had 6 pounds in it.

          and there are no leaks,

          and no one stole it, or released it or vented it.

          and there was nothing in it, then either one of the premises are wrong, or operator error, or a combination of one of the above statements are not true,

          ~~~~~~~~~~~~~

          (because even if it was absorbed or some in the oil, when a vacuum was applied there would some evaporation out of the oil and you could not hold a steady vacuum, until it was boiled out of the oil)

          on your leak testing pull a vacuum on it and see if it will hold,

          when you went to recover the refrigerant was there any pressure in the system? and if so was it proper for the temperature of the day, in other words did it show that via pressure was there liquid in the system before starting the recovery process,
          Last edited by BHD; 09-28-2007, 10:43 AM.
          Push sticks/blocks Save Fingers
          ~~~~~~~~~~~~~~~~~~~
          "The true measure of a man is how he treats someone who can do him absolutely no good."
          attributed to Samuel Johnson
          ~~~~~~~~~~~~~~~~~~~
          PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

          Comment


          • #6
            Re: Where did the refrigerent go?

            Refrigerent Elf?
            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

            I never lost a cent on the jobs I didn't get!

            Comment


            • #7
              Re: Where did the refrigerant go?

              Originally posted by BHD View Post
              could temperature (contraction and expansion) be creating some form of a intermittent leak? I never thought about this but it's an interesting concept. But when it's running there's more pressure and vibration so I would say no.

              ~~~~~~~~~~



              (because even if it was absorbed or some in the oil, when a vacuum was applied there would some evaporation out of the oil and you could not hold a steady vacuum, until it was boiled out of the oil) many times what happens is a thin film of oil will lay on the refrigerent preventing recovery, just tap the compressor and that will solve the problem.

              on your leak testing pull a vacuum on it and see if it will hold, I don't leak test by pulling a vacuum, I charge it with nitrogen

              when you went to recover the refrigerant was there any pressure in the system? No pressure whatsoever. and if so was it proper for the temperature of the day, in other words did it show that via pressure was there liquid in the system before starting the recovery process,
              Just to update, I let the electricians give training on the AC for motors and controls today and since they didn't know why my gauges were on the unit, they took them off causing me to lose my nitrogen charge. Today was a half day so it's back to square one on monday.

              BHD-is there anything you're not familar with? Are you self taught or had a lot of schooling?
              Buy cheap, buy twice.

              Comment


              • #8
                Re: Where did the refrigerant go?

                basically self taught,

                but my idea is on the vacuum is there may be a leak that is now sealed by some debris or sludge or something and if you pull a vacuum and it does not hold then there is some location that is leaking and it may open it up the hole.

                because I am thinking the same as you, it had to leak out some where.
                Push sticks/blocks Save Fingers
                ~~~~~~~~~~~~~~~~~~~
                "The true measure of a man is how he treats someone who can do him absolutely no good."
                attributed to Samuel Johnson
                ~~~~~~~~~~~~~~~~~~~
                PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                Comment


                • #9
                  Re: Where did the refrigerent go?

                  You misplaced 6 pounds of refrigerant?

                  I'm looking out my window now and see the Ozone hole growing larger

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                  • #10
                    Re: Where did the refrigerent go?

                    If only you knew how much commercial units can lose in a year. 6lbs is nothing.
                    Buy cheap, buy twice.

                    Comment


                    • #11
                      Re: Where did the refrigerent go?

                      i hope i did not read that you dont pull a vacume gear junkie. a vacume will detect allot more that nitrogen,. when i install i purge while i braze, so after the last joint is doen i fill my lineset up with 250 psi for 15 mins. after that i vacume down to 250 microns. i have found leaks vacuming that i couldnt find with nitrogen. but im sure i missunderstood you:

                      " I don't leak test by pulling a vacuum, I charge it with nitrogen"
                      how is it that so many answers are in the instructions

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                      • #12
                        Re: Where did the refrigerant go?

                        Originally posted by BHD View Post
                        could temperature (contraction and expansion) be creating some form of a intermittent leak?
                        Thats a good thought, and that does happen. Usually with old recips though. I cant ever remember having this happen to a can compressor.


                        Junkie, Proplumb is right. A vacuum is alot better for leak checking. I agree with everything he says, 'cept I'll call BS on pulling every system down to 250 microns. Most manufacturers recommend 750. I either: A) Cant charge enough to be this precise, and or B) would lose all my customers if I did. I generally shoot for 500-750, but if I'm under 1000 and the needle stays for a few minutes after turning the pump off, that refrigerant is getting turned loose.

                        Comment


                        • #13
                          Re: Where did the refrigerent go?

                          Just to clarify, after I braze my lines, I pressure test with N2 then follow it up with a vacuum. I use pretty much the same vacuum pump setup as Bill. I'm with Ruud on this one. To get down to 250 microns is time consuming, I shoot for less than 500 after isolating the system from the pump. I've had better luck finding leaks with N2.
                          Buy cheap, buy twice.

                          Comment


                          • #14
                            Re: Where did the refrigerent go?

                            Just an update; there was a leak. It was at the accumulator. It was along a welded seam, covered in rust. I tried to pull a vacuum and it did hold for an hour at 450 microns. Feeling fustrated I charged it to 300 psi with n2 and found the leak no problem. I think now that my normal psi of 150 is way to low. I think I'm going for 250 from now on.
                            Buy cheap, buy twice.

                            Comment


                            • #15
                              Re: Where did the refrigerant go?

                              Glad you found it,
                              Push sticks/blocks Save Fingers
                              ~~~~~~~~~~~~~~~~~~~
                              "The true measure of a man is how he treats someone who can do him absolutely no good."
                              attributed to Samuel Johnson
                              ~~~~~~~~~~~~~~~~~~~
                              PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                              Comment

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