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  • No Brazing?

    I just watched Ask This Old House. They were installing a Mitsubishi Mr. Slim (I think that's the name) and flared the lines on the system.

    Why no brazing?

    Thanks.

    J.C.
    Attached Files

  • #2
    Re: No Brazing?

    So easy a caveman could do it.

    Comment


    • #3
      Re: No Brazing?

      Here's a video of a similar install.

      http://www.thisoldhouse.com/toh/vide...630888,00.html

      J.C.

      Comment


      • #4
        Re: No Brazing?

        Originally posted by JCsPlumbing View Post
        I just watched Ask This Old House. They were installing a Mitsubishi Mr. Slim (I think that's the name) and flared the lines on the system.

        Why no brazing?

        Thanks.

        J.C.
        I watched it also. Flare fittings are common with the mini splits.

        I've run into units where compression fittings were used. They usually leaked. When R22 was $.50 lb wholesale, who cared.

        I couldn't believe the first flare the guy made. The tubing end was smashed. The flare came out good. Either he's damned good at flaring copper or some film editing was needed.

        Hell, I have to use flare gaskets to get my flares to seal.

        James

        Comment


        • #5
          Re: No Brazing?

          Originally posted by James P View Post
          I watched it also. Flare fittings are common with the mini splits.

          I've run into units where compression fittings were used. They usually leaked. When R22 was $.50 lb wholesale, who cared.

          I couldn't believe the first flare the guy made. The tubing end was smashed. The flare came out good. Either he's damned good at flaring copper or some film editing was needed.

          Hell, I have to use flare gaskets to get my flares to seal.

          James
          Saw the same thing. Maybe a real good flaring tool...

          J.C.

          Comment


          • #6
            Re: No Brazing?

            But again, why no brazing? That's just a couple of couplings.

            And why can flares hold the pressure? Even some solders have much higher tensile strength than flares. Right?

            Thanks. Just studying....

            J.C.

            Comment


            • #7
              Re: No Brazing?

              J. C., I think it's the business model. Not many D. I. Y./ H. O.'s can braze. This opens it up to be sold at home depot.

              Comment


              • #8
                Re: No Brazing?

                You'd have to purge the line to avoid contamination
                which in those small lines would be hell to get out.

                Last mini-split I put in (Sanyo 12KHS71) the manual
                said to put a little (R410A compatible) refrigerant oil
                on the flare connections.

                I noticed they didn't do that on the show.
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                • #9
                  Re: No Brazing?

                  We have installed 30+ Fujitsu mini splits, pipe cut square, reamed with tuning end facing the ground so pieces can't get into system. Properly flared so flare only covers about 3/4 of the flare face of the fitting. Wiped with some ester based oil and properly tightened. I have a set of torque wrenches CPS brand that I ordered at a Fujitsu school. About a C-note if I remember right.
                  1/4" 150 in lbs
                  3/8" 300 in lbs
                  1/2" 500 in lbs
                  5/8" 650 in lbs
                  Test the system side with nitrogen @500 psi. Not one leak on any one of these systems. Vac the system down to 1000 micron and your golden.
                  Proper installation of any thing is the key to no problems.
                  WE LIVE IN THE LAND OF THE FREE,
                  ONLY BECAUSE OF THE BRAVE

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                  • #10
                    Re: No Brazing?

                    That's all fine but doesn't answer my question. Respectfully.

                    Why are flared connections allowed on this? Is the pressure lower?

                    Why are flared connections not used on other systems? Is the pressure higher?

                    I do not install or work on HVAC at all, but I think if I was an installer I would go for the strongest & least likely to cause a callback connection. Seems a braze would beat a flare every time.

                    Thanks.

                    J.C.

                    Comment


                    • #11
                      Re: No Brazing?

                      this is kinda off topic
                      but flare fittings are used on 3000 psi hydraulics, called JIC fittings, there 37 degree.

                      so the fitting is not necessary a low psi fitting,

                      I think the question may be is there better connections, and I do think there is.
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                      • #12
                        Re: No Brazing?

                        Originally posted by JCsPlumbing View Post
                        That's all fine but doesn't answer my question. Respectfully.

                        Why are flared connections allowed on this? Is the pressure lower?

                        Why are flared connections not used on other systems? Is the pressure higher?

                        I do not install or work on HVAC at all, but I think if I was an installer I would go for the strongest & least likely to cause a callback connection. Seems a braze would beat a flare every time.

                        Thanks.

                        J.C.
                        Flare connections are used in refrigeration.


                        Also on AC evap. coils there's a mechanical fitting at the TXV or metering orifice.

                        James

                        Comment


                        • #13
                          Re: No Brazing?

                          Thanks James. I don't want to beat it to death but want to make sure I get it.

                          The same lines doing the same thing on other systems can be connected with flared fittings?

                          Example: 2 Ton Trane Residential HVAC unit that sits outside on a pad.

                          Thanks.

                          J.C.

                          Comment


                          • #14
                            Re: No Brazing?

                            Originally posted by JCsPlumbing View Post
                            Thanks James. I don't want to beat it to death but want to make sure I get it.

                            The same lines doing the same thing on other systems can be connected with flared fittings?

                            Example: 2 Ton Trane Residential HVAC unit that sits outside on a pad.

                            Thanks.

                            J.C.
                            The short answer is Yes.

                            For me a brazed connection is more desirable, but there are situations where a mechanical fitting is more suited. If you ever worked on larger tonnage compressors you would learn to appreciate mechanical connections like the Rotolock.

                            I've ran across many split systems that the connections were soft soldered together. Usually by plumbers who do hvac also or the local yokel handymen types who can only drop a bird turd with silfos.

                            James

                            Comment


                            • #15
                              Re: No Brazing?

                              Originally posted by JCsPlumbing View Post
                              I just watched Ask This Old House. They were installing a Mitsubishi Mr. Slim (I think that's the name) and flared the lines on the system.

                              Why no brazing?

                              Thanks.

                              J.C.

                              That's kinda like asking "Why not copper"

                              Because there is pex ;-)

                              Everyone wants fast, cheap and faster
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