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  1. #1
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    Question Best way to reach 450Psi for leak test?



    Hi there, its has been a while since I post here, currently Im doing maintanance to several units from 5HP to 20HP, I normally make the leack test with nitrogen, and I buy a "high pressure" regulator, the low side dial is mark up to 500Psi, but sadly, the higer pressure come out of it is 250 to 260PSI since it was brand new.

    The equiment uses a lot of refrigerant, and its very time consuming whait for 1hour or more to see if there is some leak, I was reading the forum and some pressure test are made even to 750Psi for 410A, not my case, I just want to reach a pressure higher than normal to avoid the waiting.

    I was thinking on using some sort of "high pressure air compressor" to reach at least 450PSI.

    https://www.ebay.com/itm/400BAR-40MP...-/401573212479

    they even come with a small water pump to cool down the head.

    Anyone has done something like this?



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    Re: Best way to reach 450Psi for leak test?

    Simply buy the CORRECT nitrogen regulator with correct range you require.
    They are available, just have to ask correct range.
    Air compressor definitely no good, as would put moisture in system & specialist compressor would be required (2 stage), the one shown in link would be very small capacity.

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    Re: Best way to reach 450Psi for leak test?

    By using air compressor, you will fill the unit with oxygen.
    Best thing is dry OFN.

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    Re: Best way to reach 450Psi for leak test?

    Oxygen + Oil = BOOOMM
    I'm back on the Pale

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    Re: Best way to reach 450Psi for leak test?

    Get the correct pressure regulator. There are no, safe, short cuts.
    Brian - Newton Abbot, Devon, UK
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    Re: Best way to reach 450Psi for leak test?

    you need to use the correct equipment to leak test correctly you also need to test at the correct pressure for the refrigerant that is in the system you can also use tracer gas to find leaks using the correct leak detector if you are testing correctly there is no reason not to find leaks you can also add a uv dye to the system to help find leaks in a working system

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    Re: Best way to reach 450Psi for leak test?

    Thanks for the kind responses.

    Im sorry for dont comment the complete Idea, by any means I was suggesting to use air to reach the higher pressure. Will describe the idea as follows;

    Use the N2 tank to fill up to lets say 200Psi to the unit to be tested.

    Re-calibrate the regulator of N2 to say 80psi, connect this to the suction port of the high pressure compressor.
    connect the output of the compressor to the manifold and charge the high pressure on the unit to be tested.

    Reasons to think in something like this are;
    Im in a range of 70 to 120Km of the units
    Most of the units are in a second floor, anotherīs in third floor.
    It will become more difficult to me to carry on two N2 Bottles for test (one in case the first dont reach the higher pressure).
    The weight and the maneuver to handle this two 9 cubit meters of N2.

    The technical data is fine and I do understand Ii, buy a higher pressure regulator, use the N2 to fill. Test,all done.

    But how do you manage you day to day operation in this case?
    carry on 2 cylinders?
    what do you do with the N2 below higher pressure test point?

    I say all this, because even I operate in medium city's with one or two brands of compressed gas dealers, its very frustrating and time consuming, to relay on them... sometimes they are closed (most of the emergency cases), or dont have the gas, or may be it will come latter on (who knows the hour).

    Will you enlighten me ?


    Time, is the issue here, when we service this units, we carry with two recovery units, two 12cfm vaccum pumps and in general all that can save us some time.

    The test is still a major issue.

    Thanks.
    -Alex.

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    Re: Best way to reach 450Psi for leak test?

    You can always use 1/4" soft copper tubing to connect from a ground floor N2 bottle up to the second floor test point.
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    Re: Best way to reach 450Psi for leak test?

    A gas booster pump like Haskel?
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

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    Re: Best way to reach 450Psi for leak test?

    I think what we europeans fail to realize, is that in europe, an 80 Liter bottle of N2 at 200 bar weighs 30-40 kg.
    While in South America a bottle of the same physical size weighs twice, and only holds 120 bar.

    First time I was in Chile, The N2 was delivered, and I grabbed one of the bottles in a bear hug to move it, and nearly threw my back out because it was just massive steel, and the pressure was only 120 bar.

    The bottles We get in Norway I can hit on the side with a wrench and it says *diiiiingggg* the bottles in South America says *dunk* they have three times the mass, less pressure and less volume.

    The obvious solution is a longes hose, leave the bottle on the ground and run a hose up to the 2nd or 3rd floor...

    But then you'd need 2 people, one down with the bottle, and one up where the unit is to watch and listen.

    And in south america, you really have to be able to work alone...


    So if martin wants to use a booster compressor to make his life easier, is he really wrong?

    I think not, sure he may get more moisture into the system, but that will be removed when he vacuumes it?

    so what's really the issue?

    Should Martin kill himself trying to lug 2 190 pound cylinders of compressed gas up two stories, or should he leave the vacuumpump running 12 hours more?

    -Cheers-

    Tycho

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    Thumbs up Re: Best way to reach 450Psi for leak test?

    Quote Originally Posted by Tycho View Post
    I think what we europeans fail to realize, is that in europe, an 80 Liter bottle of N2 at 200 bar weighs 30-40 kg.
    While in South America a bottle of the same physical size weighs twice, and only holds 120 bar.
    Hi, Wow, I dint know the weight was so much more in here. Im mean Im working here my all life.

    Yes the single carry of the two bottles of N2 is more than a worry, is a problem, and the factors I mention above are the really problems; If I use a single bottle (currently it holds 4 test for a single equipment at 250psi).

    The main Idea is to feed los pressure N2 to the compressor and pressure the compressor with it. So no more moisture, just higher pressure of test.

    Thanks for the comment.

    -Alex.

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    Re: Best way to reach 450Psi for leak test?

    .

    As well as refrigeration I also dabble in diving, scuba diving.

    We use booster compressor's to increase O2 (oxygen) in breathing air so using a booster compressor to increase the nitrogen pressure is not impossible.

    It would need some thought and design but definitely doable.

    Rob

    .
    .. ... -. .----. - / -- --- .-. ... . / -.-. --- -.. . / --. --- --- -..

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    Re: Best way to reach 450Psi for leak test?

    can you not feed in on the low pressure side and use the compressor to suck the OFN in and pressurise it?

    I did that once when I was running out of OFN, worked well for me (that one time anyway)

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    Re: Best way to reach 450Psi for leak test?

    Quote Originally Posted by knighty View Post
    can you not feed in on the low pressure side and use the compressor to suck the OFN in and pressurise it?

    I did that once when I was running out of OFN, worked well for me (that one time anyway)
    Yes I think it is feasible, but my main concern is to get an pressure test above the normal compressor ratio, for the read it is recommended to be 1.43 the high side... so 250psi times 1.43 = 357 psi... lets say 360 to 400psi.

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    Re: Best way to reach 450Psi for leak test?

    We have used - as posted before - a Haskel boosterpump (air/R134a) for this.
    We have an application (complet cycle of leak control, pressurizing, vacuuming, filling harvesters @ 3 units/hour) where we have to charge very fast a precise amount of R134a under a pressure of 20 bar.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

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    Re: Best way to reach 450Psi for leak test?

    I also don't see a problem when pressurizing with air. Perhaps blow the air through a filterdrier, the one with a removable core and big absorbing area.
    Vacuming removes the water very fast. In my evening classes, I demonstrate this with the small plastic container for a Danfoss orifice. This is anyhow a lot of water. I fill it up with water, place it in a glas container and vacuum it then. Al the water is vaporised within 2 to 3 minutes.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

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    Re: Best way to reach 450Psi for leak test?

    Quote Originally Posted by Peter_1 View Post
    I also don't see a problem when pressurizing with air. Perhaps blow the air through a filterdrier, the one with a removable core and big absorbing area.
    Vacuming removes the water very fast. In my evening classes, I demonstrate this with the small plastic container for a Danfoss orifice. This is anyhow a lot of water. I fill it up with water, place it in a glas container and vacuum it then. Al the water is vaporised within 2 to 3 minutes.
    POE oil is hygroscopic substance. This is what I am worrying about. Have you checked it after blowing the system with air?

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    Re: Best way to reach 450Psi for leak test?

    Also vacuumed POE oil, floating on water. Vacuum proces then goes slower and you see that large cooking bubbles then form underneath the oil (and splashes out the oil) but it takes some more time (in terms of 10 , 30 seconds)
    If you heat up everything, then it goes much faster.
    I think the water in the oil is largely exaggerated. Like they told us in the begiing of R134a, that you needed to have a separte manifold for R134 and that you never could attach your R134a manifold to an R12 machine.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  19. #19
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    Re: Best way to reach 450Psi for leak test?

    Quote Originally Posted by Peter_1 View Post
    I also don't see a problem when pressurizing with air. Perhaps blow the air through a filterdrier, the one with a removable core and big absorbing area.
    Vacuming removes the water very fast. In my evening classes, I demonstrate this with the small plastic container for a Danfoss orifice. This is anyhow a lot of water. I fill it up with water, place it in a glas container and vacuum it then. Al the water is vaporised within 2 to 3 minutes.
    I would like to see this experiment, it would be very interesting, and maybe I would try on a small system around.

    Thanks

    -Alex.

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