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  1. #66
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    Dude; take it easy on me will you - I am just trying to learn just how the hell all this refrigeration sh!t works. <g>

    PHM
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    Quote Originally Posted by chrigs View Post
    i am tired of the sub cooling purerersts. usually a/c guys wanabe refrig, techs.8-10-12 degrees tells you what? you have a clear col. of liquid to the txv. something a sight glass could have told you a 1/2 hour a go. i have experimented with a sg at the cu and another at the evap, and there is n0 differance in bubbles at 25 ft vert. or horizontal. have not tried it at long distances, i must confess that i started this experiment where the cu was on the roof, and by installing another sg at the evap, down below. i wouldnt have to carry a jug to the roof, i know im am a bad boy
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  2. #67
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    Jan 2007
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    Quote Originally Posted by Poodle Head Mikey View Post
    "a quiet TXV"

    That's an interesting prospective - I'm sorry I missed either it entirely, or maybe just it's significance, until now.

    When the TXV is getting partial-vapor refrigerant fed to it the resulting action inside it tends to make more noise. When the feed-column of refrigerant becomes solid all the turbulence is after the orifice - so the sounds produced are less.

    That charging method would tend toward having the least amount of subcooling possible - and still have the TXV happy. I like the idea.

    How do you hear the valve? With a stethoscope?

    PHM
    ------

    With a coffin case or WI cooler with your ear basically...(I'm @#$%ing deaf now with hearing aids so that doesn't work), just cycle the fans (don't leave them off, you'll end up with an over charge!!!). Alternately every now and then you can't do that......long shank flat blade screw driver with a solid handle end (no rubber to dampen sound). If you have a loooong LL and need to pump down with the solenoid at the condensing unit....this prevented a liquid locked high side to....but your right, virtually no SC.
    "The quality you deserve is not expensive---it's priceless"

  3. #68
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    For customers I tend to stick with what the TXV makers say their valve needs in order to control properly. But for my own systems I tend to use maybe 2 in order to keep the condenser as empty as possible.

    PHM
    ------



    Quote Originally Posted by Doug Lockhart View Post
    With a coffin case or WI cooler with your ear basically...(I'm @#$%ing deaf now with hearing aids so that doesn't work), just cycle the fans (don't leave them off, you'll end up with an over charge!!!). Alternately every now and then you can't do that......long shank flat blade screw driver with a solid handle end (no rubber to dampen sound). If you have a loooong LL and need to pump down with the solenoid at the condensing unit....this prevented a liquid locked high side to....but your right, virtually no SC.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  4. Likes Doug Lockhart liked this post
  5. #69
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    Quote Originally Posted by Poodle Head Mikey View Post
    For customers I tend to stick with what the TXV makers say their valve needs in order to control properly. But for my own systems I tend to use maybe 2 in order to keep the condenser as empty as possible.

    PHM
    ------
    Next install.....try it ......you'll be amazed how #@$%ing quiet the TXV goes when a solid column of liquid is fed to it......
    "The quality you deserve is not expensive---it's priceless"

  6. #70
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    Mar 2013
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    Quote Originally Posted by Doug Lockhart View Post
    Next install.....try it ......you'll be amazed how #@$%ing quiet the TXV goes when a solid column of liquid is fed to it......
    It's funny because that's the first thing I check to determine if a unit is low on charge vs. Restricted (txv). :grin:

    Sent from my SCH-I545 using Tapatalk

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  8. #71
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    Aug 2015
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    Manchester uk
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    A quiet tev

    Quote Originally Posted by lastguest View Post
    I agree wholeheartedly , Refrigeration is so much more specialised than ac and skilled
    Totally confused here,
    .new to the system so bare with me

    A quier tev is correct as long as the design criteria is as it should be.

    But as we all know that is not the case. I dont understand your issue??

    Please elucidate

    Pete

  9. #72
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    Jan 2015
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    the reason a reciever changes things is that its there to accept a wide range of out door temps.unlike a/c systems a refer. may need to operate at -10 f. out door amb.at that point the system needs more freon to keep a solid colomn liquid to the txv, on a 100 f day much less freon is needed, it also absorbs the liquid during the pump down cycle. i dont worry about sc so much on reciever systems, except for trouble shooting purposes . i usually clear the sg and weigh in the rest accordingto my out door condtions. this has worked well for me. 0* f- 5% full.50*f-20%. 90*f- 50% full. in the a/c business your conditions variy little, weather your in florida or minnisota, not so on the refer side. you are going to get lots of different opinions on this subject

  10. #73
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    Quote Originally Posted by chrigs View Post
    the reason a reciever changes things is that its there to accept a wide range of out door temps.unlike a/c systems a refer. may need to operate at -10 f. out door amb.at that point the system needs more freon to keep a solid colomn liquid to the txv, on a 100 f day much less freon is needed, it also absorbs the liquid during the pump down cycle. i dont worry about sc so much on reciever systems, except for trouble shooting purposes . i usually clear the sg and weigh in the rest accordingto my out door condtions. this has worked well for me. 0* f- 5% full.50*f-20%. 90*f- 50% full. in the a/c business your conditions variy little, weather your in florida or minnisota, not so on the refer side. you are going to get lots of different opinions on this subject
    Now in a heat pump (now becoming prevalent) that is variable capacity with a variable speed compressor and add in the fact that they have WIDELY variable conditions and loads and then be a cheap manufacturer and not put in a dual flow receiver or charge compensator or even an accumulator and combined with the high heads/temps resultant from running logged 'condenser' from having a TEV at both ends, coupled with the fact that since they don't have an accumulator, they run a high suction superheat of 20 degF (to hedge liquid flood back) which of course manifests itself as ~40+degF at the discharge outlet......trips out on multiple lockouts from this liquid binding causing high head temps/pressures.......but WTF do we know, we're just the blue collars spending months 'diagnosing' this sh!t and of course 'they don't pay for diagnoses time' so we work as slaves to fix the 'so called engineers' crappy engineering while they go home WITH their paycheck while we 'diagnose' for free 'till 10pm at night......for months some times. Manuf. are vastly different than when I got in the trade in '76........they partnered and respected the field guys.......they sell around us and use us as slaves to sell their POS boxes while the protect NO ONE in terms of a dealership.......they're AC Whores.....plain and simple guys...
    "The quality you deserve is not expensive---it's priceless"

  11. Likes HeatenCoolair liked this post
  12. #74
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    I agree with your logic but it's only accurate point-in-time.

    The basic concept of "ten degrees of subcooling" isn't so much that the TXV strictly requires it - although it's rated capacity IS based on having it - as it is based on the concept of the TXV always having at least Some subcooling under all possible fluctuations of operation.

    PHM
    -------


    Quote Originally Posted by Doug Lockhart View Post
    Next install.....try it ......you'll be amazed how #@$%ing quiet the TXV goes when a solid column of liquid is fed to it......
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  13. Likes Doug Lockhart liked this post
  14. #75
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    Nov 2016
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    Very good topic for discussion.

    I would like to know, whats the good super heat and sub cooling for a 404 reach in freezer with TXV. Ambient is around 76 and box temperature at 30.

    Thank you.

  15. #76
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    Quote Originally Posted by sam's View Post
    Very good topic for discussion.

    I would like to know, whats the good super heat and sub cooling for a 404 reach in freezer with TXV. Ambient is around 76 and box temperature at 30.

    Thank you.
    Sam with low temp......you need to watch the superheat at the compressor inlet......superheat means nothing if your running a SL/LL Hxer and run 50 degF superheat coming into the compressor.......you'll burn up the compressor/break down the oil very quickly...
    "The quality you deserve is not expensive---it's priceless"

  16. #77
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    Nov 2016
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    Doug,
    Thank you very much for your reply.

    Can you please tell me whats the SL?LL Hxer?

  17. #78
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    Quote Originally Posted by sam's View Post
    Doug,
    Thank you very much for your reply.

    Can you please tell me whats the SL?LL Hxer?
    Suction Line / Liquid Line Heat Exchanger
    "The quality you deserve is not expensive---it's priceless"

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