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    Testing digital manifold

    bignozzle
    bignozzle Member Posts: 31
    in A-C, Heat Pumps & Refrigeration

    Good morning, I just bought a used testo 557. How can I pressure test it? I don’t think it would be good to submerge in water like my old dial gauges.

    Thanks in advance.

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    Comments

    • Ironman
      Ironman Member Posts: 7,698

      Do you have an electronic leak detector?

      Bob Boan
      You can choose to do what you want, but you cannot choose the consequences.
    • ChrisJ
      ChrisJ Member Posts: 16,565

      I'd think a reasonably quick test would be to pull a vacuum on it and valve it off and wait to see if it climbs.

      I know that doesn't guarantee it won't leak under positive pressure but it's probably a safe bet.

      Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

    • bignozzle
      bignozzle Member Posts: 31

      no,don’t have electronic leak detector.

    • mattmia2
      mattmia2 Member Posts: 12,244
      https://forum.heatinghelp.com/discussion/comment/1806120#Comment_1806120

      Or better yet pressurize it with nitrogen and see if it holds.

    • bignozzle
      bignozzle Member Posts: 31

      I installed a vcrt on the high pressure side and put caps on the other ports. I pressurized to 300 psi. I shut valve on vcrt. I took the knobs off and put bubble leak detector around the valve stems and caps. No bubbles. I did 10 minute test and it lost .4 psi. Not sure where the pressure went.

    • ratio
      ratio Member Posts: 3,950

      Internal, either the transducer connection or the transducer itself.

      Or, just temperature equalization. 10 minutes isn't very long.

    • mattmia2
      mattmia2 Member Posts: 12,244

      Wait another 10 minutes, temp changes could account for .4 psi at 300 psi. If it keeps going down as you wait longer there is a leak, if it stabilizes or fluctuates up and down it is just error in the equipment or expansion and contraction.

    • bignozzle
      bignozzle Member Posts: 31

      I don’t think it’s expansion or contraction because the nitrogen bottle and the gauge were in my garage for a couple of days before.

      Thanks for the input.

    • ChrisJ
      ChrisJ Member Posts: 16,565
      https://forum.heatinghelp.com/discussion/comment/1806482#Comment_1806482

      Hoses expanding?

      Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

    • mattmia2
      mattmia2 Member Posts: 12,244

      .1% isn't a lot of electronics to drift either. give it an hour or 2, if it keeps going down there is a leak. the temp of the nitrogen changes when you change the pressure on it too although it should get cooler when you lower the pressure from the tank pressure.

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