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Thread: Modified paper test

  1. #1
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    Modified paper test

    I have a possible new test method for testing a partially clogged condenser or air filter/evaporator. This is similar to the positive pressure paper test which tests the push of the fan for fully clogged condensers. The only difference is it tests negative pressure or the pull of the fan as well as turbulence. The air filter/evaporator test involves folding a piece of computer paper into 1/2 and placing along the grille to locate a restriction of airflow. Requires an air filter in place so negative pressure is distributed correctly. This test could also be used for condenser coils by folding into 1/3 and placing along this coil to determine a restriction. Comments welcome.

  2. #2
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    I use my hat, it is of the Fedora design (think Indiana Jones type).

    If a condenser will hold it on the vertical side and also how well it "floats" above the fan discharge gives me a feel of coil obstructions. A few years of practice though.

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  4. #3
    R600a's Avatar
    R600a is offline Professional Member*/Membership Committee
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    I think it's much easier to feel the cone of air coming out of the top of the condenser and when it's restricted you can feel it throwing the air more out towards the sides instead of a nice straight sided cylinder of air like it should be.
    "Is this before or after you fired the parts cannon at it?" - senior tech
    I'm tired of these mediocre "semi flammable" refrigerants. If we're going to do it let's do it right.
    Unless we change direction we are likely to end up where we are going.
    "It's not new, it's better than new!" Maru.

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    I use my pressure gauges and piping sensors to first see if a restriction/problem is present…

    I do use my hat sometimes as a fast check and my flir thermal camera…it shows everything…

    I also use my temperature probe to check if a condenser or evap is dirty by the temp difference rise/fall

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    R600a's Avatar
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    My rule of thumb is if I haven't washed it in the last 6 months it's dirty. I've had too many high pressure trips on units other techs had "just washed".
    "Is this before or after you fired the parts cannon at it?" - senior tech
    I'm tired of these mediocre "semi flammable" refrigerants. If we're going to do it let's do it right.
    Unless we change direction we are likely to end up where we are going.
    "It's not new, it's better than new!" Maru.

  8. #6
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    Thread Starter
    Basically appreciate the comments. I'll try the hat method and see if I can get it to work for "locating". I'll use the CTOA method if I want to know condenser is clogged.

  9. #7
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    Feeling the air coming off the fan is the fastest and easiest method to gauge dirtyness.

    If the pattern is flattened, and going sideways, it's dirty.

    No tools needed.

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  11. #8
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    Quote Originally Posted by R600a View Post
    My rule of thumb is if I haven't washed it in the last 6 months it's dirty. I've had too many high pressure trips on units other techs had "just washed".
    Apparently this period has been quite eventful for you...

  12. #9
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    Yeah this must be!

  13. #10
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    Condenser & liquid line approach is the correct method.

    Once you learn it you may find your own short cuts for particular models. Static can vary greatly between models.

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