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  1. #1
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    connecting gauges with minimun fridge loss



    looking for opinions for connecting gauges with minimum refrigerant loss, with lines with no ball valves.
    Should we shut down system, then screw in discharge service valve to connect discharge line, then should suction service valve be shut before connecting suction line.
    I have been tought to just screw them on quickly and let it spray, but I am more aware of effects now.
    Explanations would be greatly appreaciated. Will I be better buying new lines with ball valves, etc.

    Nev



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    Re: connecting gauges with minimun fridge loss

    Yes, ball valves are ideal. You can buy adaptors to fit the end of your existing hoses if you want.
    http://www.hawco.co.uk/Manifold-and-Hoses_629_p.aspx

    Closing the valves will not make any difference unless it is a back-seating valve.

    You can also get screw on adaptors with non return valves, which I tend to use on my high pressure hose as it only releases the small amount of gas that was in the fitting itself.
    http://www.hawco.co.uk/Quick-Connectors_516_p.aspx

    Also, when you are disconnecting your hoses start with the high pressure hose, with the system running, valve shut; then open your manifold valves to allow the suction pressure to relive the high pressure gas back to the low pressure side. This will also clear any liquid as well. Now disconnect the low pressure hose and you should be left with some low pressure vapour in your manifold set.
    Last edited by Brian_UK; 04-03-2011 at 12:13 AM.
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    Re: connecting gauges with minimun fridge loss


    ...........................

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    Re: connecting gauges with minimun fridge loss

    I use ball valves which in my opinion are great.

    Also setting your lines up correctly helps alot, i dont know the correct terminology but i see many engineers with the "schrader depreser" on there lines to far out. This mean as they disconnect there lines the schrader stays open for a longer period of time once the seal between the rubber and brass has been lost.
    A simple schrader key adjusts this.

    hope this makes sense :/

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    Re: connecting gauges with minimun fridge loss

    The best way to minimize refrigerant loss is to only connect gauges when all other avenues have been exhausted.A lot of the time with a good thermometer and a bit of thinking you can achieve the same results.Failing that use quick couplers
    Cheers
    Stu
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    Re: connecting gauges with minimun fridge loss

    .

    Your talking AC systems only though???

    Why not use quick couplers?

    With AC and gauge lines you will always lose what is in the line
    no easy way round it realy. The quicker you take the fitting off
    the less you lose.

    All the best

    coolrunnings

    .

    .

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    Re: connecting gauges with minimun fridge loss

    Makes perfect sense. Never knew the schrader depreser was adjustable. Would they be set ok from new without interferience. Never took schrader depreser out of line for likes of recovery as use recovery lines.

    Quote Originally Posted by SkyWalker View Post
    I use ball valves which in my opinion are great.

    Also setting your lines up correctly helps alot, i dont know the correct terminology but i see many engineers with the "schrader depreser" on there lines to far out. This mean as they disconnect there lines the schrader stays open for a longer period of time once the seal between the rubber and brass has been lost.
    A simple schrader key adjusts this.

    hope this makes sense :/

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    Re: connecting gauges with minimun fridge loss

    I've found the Refco lines with the plastic seal squirt like nobodys business when removing them. Types that use a rubber gasket to seal seem better as the rubber is thicker the the plastic seal. You can undo the hose and by the time the schrader depressor has lifted, the rubber seal is still stopping the refrigerant coming out. Then it's just the liquid in the line to worry about.
    As stated it's best to try and get the liquid back through to the suction valve. You could close a liquid valve and pump the system down the remove the gauge when pressure is 0psig.

    Andy.
    Health and safety first..........unless I'm in a hurry.

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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by cool runings View Post
    .With AC and gauge lines you will always lose what is in the line
    no easy way round it realy. The quicker you take the fitting off
    the less you lose.

    coolrunnings

    .
    Prior to disconnecting your gauges, close the liquid line valve to put the A/C system into pump down mode, then, as you approach 0 psig, disconnect your gauges and switch off the unit. Then open the valve and switch back on.
    This method saves the refigerant loss.
    I'm back on the Pale

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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by frank View Post
    Prior to disconnecting your gauges, close the liquid line valve to put the A/C system into pump down mode, then, as you approach 0 psig, disconnect your gauges and switch off the unit. Then open the valve and switch back on.
    This method saves the refigerant loss.
    beat me to it

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    Re: connecting gauges with minimun fridge loss

    line tap valves-joke!!

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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by install monkey View Post
    line tap valves-joke!!
    Who mentioned Line Tap valves?
    I'm back on the Pale

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    Re: connecting gauges with minimun fridge loss

    I use Yellow Jacket thingo hoses with the valve in the swivel nut connector, absolute minimal lose. Had one play up, stripped it out and cleaned and replaced o/ring, now good as golden. I can seriously recommend them.

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    Re: connecting gauges with minimun fridge loss

    .

    With fridge system I agree that pumping down is simple so
    removing gauge lines with minimal lose is simple.

    With AC all the best will in the world does not make it simple
    to pump the systems down. Yes they can be pumped down
    but the majority of guys who work on AC have no idea how
    to pump them down so they could safely remove the gauge
    lines.

    I'm not getting at AC guys but the levels of knowledge are a
    lot lower than what is desired.

    coolrunnings.

    Ps

    Before I get flamed, just think who asked the question in the first
    place and the responce the post has generated. If a 36 year old
    needs to ask how you take gauge lines off, what does that say
    about the level of training and supervision in the AC industry.

    .

    .
    Last edited by cool runings; 13-03-2011 at 12:35 AM.

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    Re: connecting gauges with minimun fridge loss

    Didn't beat me though.

    Right, back to my trumpet practice,
    Andy.
    Last edited by Tayters; 13-03-2011 at 11:49 AM. Reason: Anyone know how to delete posts?
    Health and safety first..........unless I'm in a hurry.

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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by aircool View Post
    beat me to it
    Didn't beat me though.

    Right, back to my trumpet practice,
    Andy.
    Health and safety first..........unless I'm in a hurry.

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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by cool runings View Post
    .

    With fridge system I agree that pumping down is simple so
    removing gauge lines with minimal lose is simple.

    With AC all the best will in the world does not make it simple
    to pump the systems down. Yes they can be pumped down
    but the majority of guys who work on AC have no idea how
    to pump them down so they could safely remove the gauge
    lines.

    I'm not getting at AC guys but the levels of knowledge are a
    lot lower than what is desired.

    coolrunnings.

    Ps

    Before I get flamed, just think who asked the question in the first
    place and the responce the post has generated. If a 36 year old
    needs to ask how you take gauge lines off, what does that say
    about the level of training and supervision in the AC industry.

    .

    .
    Are you comfortable up there on your high horse ?
    Or maybe you have a poor view from your soap box through your rose tinted glasses !!
    What's with the sudden change of opinion ??
    And i quote...With AC and gauge lines you will always lose what is in the line
    no easy way round it realy. The quicker you take the fitting off
    the less you lose.

    coolrunnings
    But what would I know considering my levels of knowledge are in your opinion a lot lower than what is required !
    Remember !!!..Opinions are like arseholes , everyone's got one!
    A lot of us in the A/C trade ended up here by choice !
    The OP is more than likely referring to splits but a person of your superior knowledge and ability would obviously know that the A/C industry consists of many more machines and applications where schrader valves are not the norm.
    As for getting flamed for your comment's .
    What did you expect with a comment as generalising as that ???
    Cheers
    Stu
    Last edited by stufus; 13-03-2011 at 07:36 PM. Reason: punctuation !!!!!!
    Tool's ? check ! Condom's ? check !
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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by cool runings View Post
    .

    With fridge system I agree that pumping down is simple so
    removing gauge lines with minimal lose is simple.OTE]

    First, question is not how prevent loss when removing hoses but how to prevent loss when connecting hoses.
    You cannot pump down system without monitoring pressure because you could suck air if system is in vacuum. How will you tell if system is not in vacuum without gauges connected?

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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by stufus View Post
    Are you comfortable up there on your high horse ?
    Or maybe you have a poor view from your soap box through your rose tinted glasses !!
    What's with the sudden change of opinion ??
    And i quote...With AC and gauge lines you will always lose what is in the line
    no easy way round it realy. The quicker you take the fitting off
    the less you lose.

    coolrunnings
    But what would I know considering my levels of knowledge are in your opinion a lot lower than what is required !
    Remember !!!..Opinions are like arseholes , everyone's got one!
    A lot of us in the A/C trade ended up here by choice !
    The OP is more than likely referring to splits but a person of your superior knowledge and ability would obviously know that the A/C industry consists of many more machines and applications where schrader valves are not the norm.
    As for getting flamed for your comment's .
    What did you expect with a comment as generalising as that ???
    Cheers
    Stu
    I knew this would happen.

    Losing a bit of refrigerant while fitting and removing is going to happen.
    If you have the facility to pump down then do it and save the loss,
    if you can only get the gauges to the same pressure as the suction then
    at least the liquid has been put back into the system.

    You can only do what you can do with the equipment you have and the
    requirement is to take all reasonable steps to minimise losses, not totaly
    stop it.

    So kwick couplers and ball valves are great. The self sealing ones look good
    and if they work, fanstastic. Some 410a systems only have one access point
    so getting gas out of the lines is a different ball game altogether.

    So if I'm passionate about my skill and trade and if I want to keep the standards
    as high as I have been expected to work, I will not apologise for that.

    if that sounds to you like I'm putting people down, that I do apologise for.
    People need to learn, but a lot of companies out there think that their guys
    are qualified because they have a Fgas ticket and can put pipes indoors from
    outside.

    Any one working on refrigeration & AC systems should be able to stand infront
    of the system and work out how to fit gauges, every time and with minimal fuss.

    Call that being on my soap box, but I call it pride in my work.

    Give the guy his due, he asked and is prepared to learn. The day we stop asking
    is the day we are in trouble.

    I would like to know who taught him?
    I would like to know what company employs somone and not train them in the basics?

    So if you are happy with the level of ability in our industry, thats OK. I'm not. I think standards
    are slipping and I think we are becoming a component changing trade and not a trade that
    I used to know that could ask why, fault find and work out why.

    Maybe I'm old fashioned, maybe I'm balancing on my soap box way up on my high horse..........
    I'd like to think I had standards........

    Maybe I'm wrong..

    All the best

    coolrunnings..

    .

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    Re: connecting gauges with minimun fridge loss

    My problem is not with your passion for the trade or your ability or your standards !
    The idea of the forum is to facilitate people with knowledge to impart that knowledge to those who wish to learn,as you said the OP is showing a desire to learn but ...the fact it displays 36 years of age in his profile is irrelevant to the topic as for all we know he could have just started in the trade,or is there a cut of point??
    My problem lies firmly with your condescending statement that the majority of "A/C guys" don't know how to pump down a system.
    I don't know how it works where you are but where I am you can't just serve your time at A/C you may work for an A/C company but you serve your time as a refrigeration technician ,just as I have done and I have worked on it all from window rattlers to multi megawatt industrial applications .As the saying goes it's not a job it's a lifestyle.
    I personally made a decision to specialize in the A/C side of thing's as did many others on this forum .
    Does that mean my abilities and qualifications are not as valued as those of someone who chose industrial refrigeration.
    I don't think so.
    There are people in all manner of profession's who don't know their arse from their elbow which is unfortunate for all concerned.
    As for standards,yes I have standards ,High one's which I strive to maintain and encourage those around me to maintain also.
    One of the standards I have is called respect.
    I respect people for their abilities and their attitude,Yes it has to be earned and each has to earn theirs .
    Therefore I don't generalise when speaking about trades.(except plumbers)
    You can't go around tarring everyone with the same brush.
    I don't consider myself "old hat "or "new shoes" but I believe everyone deserves a fair crack of the whip !
    But Maybe I'm wrong
    Condescending mean's talking down to people in case you don't know

    Cheers
    Stu
    Last edited by stufus; 14-03-2011 at 10:06 AM.
    Tool's ? check ! Condom's ? check !
    If you can't fix it , f*ck it !!!

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    Re: connecting gauges with minimun fridge loss

    Its me the 36 year old asking about the way other people take gauges off.

    Just to let you know I changed my career from a ventilation engineer 4 years ago to better myself and was trained by a refrigeration engineer in a small 1 man business who basically showed me things once and then left me to it. I am competent at my job though every day is still a learning day. I was only looking for other peoples opinions and got varied feedback, mostly good. As I thought this forum was about advice from more experienced engineers and people with similar problems.

    Anyway thanks for the putdown.
    Quote Originally Posted by cool runings View Post
    .

    With fridge system I agree that pumping down is simple so
    removing gauge lines with minimal lose is simple.

    With AC all the best will in the world does not make it simple
    to pump the systems down. Yes they can be pumped down
    but the majority of guys who work on AC have no idea how
    to pump them down so they could safely remove the gauge
    lines.

    I'm not getting at AC guys but the levels of knowledge are a
    lot lower than what is desired.

    coolrunnings.

    Ps

    Before I get flamed, just think who asked the question in the first
    place and the responce the post has generated. If a 36 year old
    needs to ask how you take gauge lines off, what does that say
    about the level of training and supervision in the AC industry.

    .

    .

  22. #22
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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by refcon32 View Post
    Its me the 36 year old asking about the way other people take gauges off.

    Just to let you know I changed my career from a ventilation engineer 4 years ago to better myself and was trained by a refrigeration engineer in a small 1 man business who basically showed me things once and then left me to it. I am competent at my job though every day is still a learning day. I was only looking for other peoples opinions and got varied feedback, mostly good. As I thought this forum was about advice from more experienced engineers and people with similar problems.

    Anyway thanks for the putdown.
    Ignore it mate
    The day we stop asking questions ,we may pack it in ,not because we know it all ,because we will go no further.
    Best of luck
    Stu
    Tool's ? check ! Condom's ? check !
    If you can't fix it , f*ck it !!!

  23. #23
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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by stufus View Post
    Ignore it mate
    The day we stop asking questions ,we may pack it in ,not because we know it all ,because we will go no further.
    Best of luck
    Stu
    Well said stufus
    If you use a schrader connection then pump the system down as far as possible if not all the way to about 1psi then turn unit off. If you have used hoses with a valve fitted then close the valve and remove hose and open valve,turn unit back on again. Minimal loss as far as I am concerned.

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    Re: connecting gauges with minimun fridge loss

    Quote Originally Posted by stufus View Post
    One of the standards I have is called respect.
    I respect people for their abilities and their attitude,Yes it has to be earned and each has to earn theirs .
    Therefore I don't generalise when speaking about trades.(except plumbers)
    You can't go around tarring everyone with the same brush.
    I don't consider myself "old hat "or "new shoes" but I believe everyone deserves a fair crack of the whip !
    But Maybe I'm wrong
    Condescending mean's talking down to people in case you don't know

    Cheers
    Stu
    Your right and I'm wrong

    As for condescending meaning talking down to people in case I did not know
    I do now even if I did not then

    Just recently I have seen a lot of guys with poor training and no support from
    their companies. Some have no incentive to better themselves and are happy
    to just do what they do, good, bad or indifferant.

    So I reacted wrongly......


    Quote Originally Posted by refcon32 View Post
    Its me the 36 year old asking about the way other people take gauges off.

    Just to let you know I changed my career from a ventilation engineer 4 years ago to better myself and was trained by a refrigeration engineer in a small 1 man business who basically showed me things once and then left me to it. I am competent at my job though every day is still a learning day. I was only looking for other peoples opinions and got varied feedback, mostly good. As I thought this forum was about advice from more experienced engineers and people with similar problems.

    Anyway thanks for the putdown.
    No explanation needed mate and sorry for the put down. In my book you are the better
    man for asking in the first place and my responce to you was wrong.
    I stand by what I said about standards but I judged you and I was wrong.....

    You keep on asking mate...........


    Quote Originally Posted by stufus View Post
    Ignore it mate
    The day we stop asking questions ,we may pack it in ,not because we know it all ,because we will go no further.
    Best of luck
    Stu
    The day we stop asking is the day we are in trouble.
    The day we stop learning is the day we are in trouble.

    I'm still learning

    Oh and Stu I'll let your comment about plumbers go because I don't judge people

    All the best guys

    coolrunnings

    .
    Last edited by cool runings; 18-03-2011 at 01:20 AM.

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    Re: connecting gauges with minimun fridge loss

    We are just one big happy family , It's like the Walton's with extras.
    Cheers
    Stu
    Tool's ? check ! Condom's ? check !
    If you can't fix it , f*ck it !!!

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    Re: connecting gauges with minimun fridge loss

    About the question as how to connect with minimal refrigerant loss, there are service adaptors with spindle valves which do seal off the hoses when back-seated. After you connect them to a schrader you extend the spindle, opening the valve and depressing the schrader in your service port. I like the idea!

    With all the consideration for avoiding refrigerant loss, what about the issue of avoiding ingress of small amounts of air? Suppose you have got hoses with ball valves (or spindle valves as above), there is still a small amount of air in the fitting which could come into the system if you do a pumpdown.

    So the only option if working both cleanly and without any risk of air ingress would be:
    First recover refrigerant in your hoses and evacuate them, valves closed.
    Then, connect ball valves to service port, open very briefly and recover the mixed air/refrigerant mixture from the hoses with ball valves closed.

    I wouldn't see any other way to avoid the air ingress - unless working about atmospherica pressure at all times.

    -Dave

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