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Thread: Upsidedown U

  1. #1
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    Wink Upsidedown U



    Hi to every one
    I need some explanation of this upsidedown U in the liquid line of refrigeration system of 15 tons copeland compressor?
    Thank You
    Attached Images Attached Images



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    Re: Upsidedown U

    Depends on the difference in levels between the condenser and the evaporator.

    Maybe it is to stop refrigerant draining from one place to another during the shutdown period.

    The silly answer is that the technician who fitted it had a bad back and could not bend down any further
    Brian - Newton Abbot, Devon, UK
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    Re: Upsidedown U

    Hi afak,

    I cannot think of any practical reason for doing this.
    If all else fails, ask for help.


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    Re: Upsidedown U

    1) He made a **** up with the pipe bender and bent it up instead of down, or,

    2) He had bad eyesight so he raised the position of the sightglass so he could see it easier



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    Re: Upsidedown U

    I can't belive it 1 of my best installs ends up in the bodgers section.

    I passed C&G and this was my test piece

    Lrac
    Grumpy men live longer

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    Re: Upsidedown U

    Sight glass before drier?
    I knew someone who put a "coffee mug stand" in some pipework once!

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    Re: Upsidedown U

    Much easier to solder if it's a mens height.
    Sightglass is indeed wrong installed
    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: Upsidedown U

    For my money it just makes changing the drier easier when you measure a 2k temp diff.
    Takes a licking, keeps on ticking.

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    Re: Upsidedown U

    lol I was just going to say to make it easier to change the filter, though he forgot the mug holder so He can have his cofe' on the discharge line, and the beer holder on the low side line.

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    Re: Upsidedown U

    correct me if i'm going blind but can i see a copper access port on the drier???????

    I think its a suction drier

    Lrac
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    Re: Upsidedown U

    the chap who put it in obviousley has a bad back and cant bend down to change the drier ,or justs has a bit of a flair for theese things,very nice.

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    Re: Upsidedown U

    There is solenoid valve before the TEV inlet .The man is with healthy backbone too .

  13. #13
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    Re: Upsidedown U

    Hi,

    The upsidedown U I think is to prevent oil carry-over and accumulation in the coiling coils. What do you think guys?

    Caesar

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    Re: Upsidedown U

    Isn't this extra height to increase the static head pressure on the liquid line to prevent flash bubbles reaching the TEV?
    Or once its got over the top the liquid then flows downhill all the way !!

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    Re: Upsidedown U

    Quote Originally Posted by Electrocoolman View Post
    Isn't this extra height to increase the static head pressure on the liquid line to prevent flash bubbles reaching the TEV?
    Or once its got over the top the liquid then flows downhill all the way !!
    Impossible, the liquid goes the same height up as it goes down, so the net gain is 0.0.

    Oil carry over? We're talking about the liquid line where the oil can go perfect in solution with the liquid. Even if the liquid line goes up 30 ft, you still will have refrigerant migration if temperature inside is lower then outside temperature.
    Last edited by Peter_1; 15-07-2007 at 01:11 PM.
    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: Upsidedown U

    Hi

    second hand unit that has been installed before, liquid line went up to the indoor on the last installation and was not changed for this one

    Kind Regards Andy
    If you can't fix it leave it that no one else will:rolleyes:

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    Re: Upsidedown U

    These upside U bends are known as P traps. It is used when the location of the condensing units and the Evaporator units are one above the other at a vertical height. These prevent the oil flowing and not returning from the evaporator. I hope I am correct.

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    Re: Upsidedown U

    These upside U bends are known as P traps. It is used when the location of the condensing units and the Evaporator units are one above the other at a vertical height. These prevent the oil flowing and not returning from the evaporator. I hope I am correct.
    Who above whom ? I knew and used suction line U oil trap if the condenser is mounted higher than the evaporator .Another U trap used in the discharge line if the compressor is mounted lower than the condenser . More explanation on the so-called liquid line U trap and should it be upside down or not?

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    Re: Upsidedown U

    I think Afak just won the "shortest message with the most 'clickable' words" ...lol

    Chillin
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    and go get a cuppa

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    Re: Upsidedown U

    Hi Afak,

    I am sorry for stating a wrong intepretation. I did not have a clear view of the photograph attached. To be honest there is no reason or advantage to take up the liquid line and drop it down.

    Do you have the Heatcraft Installtion Manual and the Engineering Manual. It gives a lot of informations. In case you do not have it, you can down load the same from www.heatcraftrpd.com or send me a PM giving your e mail id, and I shall mail the same to you.

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    Re: Upsidedown U

    afak,

    There is no advantage or reason to use a trap in the liquid line. It serves no purpose in this application. Traps are only used in gas lines in the manner you mentioned (for almost 100% of HVAC and commercial refrigeration).

    In ammonia systems it is common to see traps in condenser refrigerant drain (liquid) lines. But in this case they are used to provide a seal between individual condenser coils.
    If all else fails, ask for help.


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    Re: Upsidedown U

    Looks like it was strictly to make things easier.

    Ken

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    Re: Upsidedown U

    Thank You US Iceman
    Thank You chillin out
    Thank you to you all
    I think that he tried to put additional device from his own to protect evaporate from overfluided in addition to the solenoid valve and TEV ,may be thinking that they are not enough. A Little information about head pressure and the effect of the pressure difference of the two sides of the system in on-period and off-period on the liquid might help him to leave this U . Or he should made its hight some hundred feet and calculate exactly the difference between the condenser pressure in on and off periods to control the liquid flow and throw away the solenoid valve !

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    Re: Upsidedown U

    Hi everybody

    From the first glance, the system cooling capacity is big 15 ton (52.7 kW) and there is suction-line heat exchanger. Therefore, i expect that this U tube was installed to more protection for the compressor from liquid slugging during off-cycle. Although there is solenoid valve and it can entrap a lot of the refrigerant in the receiver drier but the refrigerant flow rate is rather high due to the big capacity and still some amount of refrigerant will migrate to the lower-side "evaporator and suction line". During the off-cycle, the refrigerant liquid is settled in the horizontal suction-line heat exchanger due to the action of inverted U tube and this liquid has a quite higher temperature than that in the suction line so there is heat transfer takes place in the insulated soldered tubes "suction-line heat exchanger" and this heat transfer tries to boil off any accumulated liquid in the suction line and thus protects the compressor from flood back problem during starting. therefore the heat exchanger can work during the on-cycle and off-cycle by exploiting the heat content in the refrigerant which entrapped in the liquid line. I hope it is clear

    Best regards

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    Re: Upsidedown U

    You are all wrong

    It is a carrying handle.

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    Re: Upsidedown U

    Its a drying loop. For drying your coats on.

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    Re: Upsidedown U

    Oh come on now.... You people are just guessing about this!
    If all else fails, ask for help.


  28. #28
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    Re: Upsidedown U



    Come on people here are the real reasons?
    1, Natural air flow is allowed to pass over the liquid line for extra sub cooling.

    2, The tape on the suction makes for a cheap heat exchanger.

    3, The position of the liquid lines stays in the shade all day.

    4, This is Iraq so not having all the pipes together means less chance of ammunitions hitting it.

    5, Did the unit feed a room upstairs but with the top of the building blown off they moved the indoor unit downstairs.

    Or is it just a c**p job while under fire
    Grumpy men live longer

  29. #29
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    Re: Upsidedown U

    This is the first Refrigeration Koan .

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    Re: Upsidedown U

    If you have some ice cream, i will give you some.

    If you have no ice cream, i will take it away from you.

    It is an ice cream koan.

    Jon

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    Re: Upsidedown U

    To me it looks like it was installed by a backyarder and is well suited have this whole thread relocated to the " Hall of Shame " thread started by Temprite .
    The thing I noticed was the stunning brickwork and how the unit is not square with the wall behind .

    By the look of the unit and pipework , whats the problem its all the same ???

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