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  1. Replies
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    1,777

    O Valves are balanced ported. They should...

    O Valves are balanced ported. They should regulate superheat down to approximately 25% of the valve's nominal capacity. I don't think the fact that the valves might be marginally oversized is the...
  2. R-22 is not a great low temperature refrigerant....

    R-22 is not a great low temperature refrigerant. The thermodynamic properties of R-22 result in high discharge temperatures in LT applications.

    So, it's a choice between oil decomposition and...
  3. R-404A and R-507 are not going to be phased out...

    R-404A and R-507 are not going to be phased out anytime soon. It's use in new supermarket applications will not be allowed starting January 2017, with commercial refrigeration applications being...
  4. Replies
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    Don't know of anything that can be used to braze...

    Don't know of anything that can be used to braze Cooper. :LOL:
  5. Replies
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    1,149

    Interesting article on copper plating: ...

    Interesting article on copper plating:

    http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1074&context=icec

    Regarding the presence or lack of acid...there are organic acids, which are the...
  6. Thread: Drop in for R22

    by bunny
    Replies
    19
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    1,058

    Aside from any performance related issues,...

    Aside from any performance related issues, anytime you mix one refrigerant with another, you form another blend. The problem is, you have no idea what the new pressure temperature relationship of...
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    Do not remove the piston when brazing this valve...

    Do not remove the piston when brazing this valve in...you'll never get it back inside the body.
  8. Replies
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    360

    The equalizer should be located DOWNSTREAM of the...

    The equalizer should be located DOWNSTREAM of the sensing bulb.

    Should the valve become worn, resulting in liquid leaking around the pushrods and flowing through the equalizer to the suction...
  9. Thread: EXV and more

    by bunny
    Replies
    3
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    446

    That's not a KELVIN controller. It's the...

    That's not a KELVIN controller. It's the interface tool for adjusting settings on the older style controllers.....not a current item.
  10. I too am curious as to why this rack has a...

    I too am curious as to why this rack has a discharge bypass valve.

    How many circuits on the rack, what Btu capacity, how many compressors and what capacity are they?

    It is unusual to see a rack...
  11. Replies
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    612

    The Y-1155 is the best option for mechanical...

    The Y-1155 is the best option for mechanical control...it's a dual ported valve.

    An electric valve is really the best method for controlling the subcooler.
  12. More to the point, RTUs typically don't have...

    More to the point, RTUs typically don't have receivers. And you cannot use flooded head pressure control (headmaster or other versions) without a receiver.

    So, while it's not ideal, you typically...
  13. Replies
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    1,317

    The TEV capacity is based on three system...

    The TEV capacity is based on three system conditions: Liquid temperature, evaporator saturation temperature, and pressure drop across the valve port.

    Ideally, all three of those conditions would...
  14. Thread: headmaster

    by bunny
    Replies
    35
    Views
    1,832

    One of the failure modes of a headmaster is that...

    One of the failure modes of a headmaster is that the element diaphragm weakens and cracks. Eventually, the element will fill up with refrigerant. Since there's no flow, and since the element has...
  15. Replies
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    503

    If a manufacturer has a 10 ton application, and...

    If a manufacturer has a 10 ton application, and has chosen to use the ER valve, the 12.5 ton valve would be the best choice. The next smallest valve is a nominal 8 ton valve.

    The ER is a balanced...
  16. Replies
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    1,951

    If this is an R12 (or R502) system, and the TEV...

    If this is an R12 (or R502) system, and the TEV was deemed defective and replaced in the last few years, the replacement element would have a sticker showing several refrigerants.

    This doesn't...
  17. Thread: Valve Plates

    by bunny
    Replies
    7
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    818

    United Refrigeration is a certified...

    United Refrigeration is a certified Carrier/Carlyle compressor distributor.
  18. Replies
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    1,230

    There's still quite a few Hussmann TD systems in...

    There's still quite a few Hussmann TD systems in the Northern CA area. They are 2 stage R-22 systems using Carrier 5H compressors.

    And if I can put a plug in for United Refrigeration, they stock...
  19. Replies
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    653

    In addition to a worn rear main bearing, it's...

    In addition to a worn rear main bearing, it's important to make sure the motor coupling is properly aligned. A misaligned coupling will destroy the seal.
  20. Replies
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    653

    No tool is required to replace the shaft seal in...

    No tool is required to replace the shaft seal in a 5F/5H Carrier compressor. There is a tool required to remove/replace the rear main bearing.

    I've attached the service literature for the 5F/5H...
  21. Replies
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    1,230

    Probably a typo in your post, but those are...

    Probably a typo in your post, but those are Carrier 5H60 compressors.

    Good compressors, and still in use today.
  22. Replies
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    1,357

    R-22 ODP = .05, so not a particularly dangerous...

    R-22 ODP = .05, so not a particularly dangerous threat to the ozone layer. And its relatively moderate GWP of 1700 is considerably less many refrigerants that have not been banned...so not a huge...
  23. Replies
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    1,580

    As I said in my post, this is the result of a...

    As I said in my post, this is the result of a liquid line running through the return air plenum of a low temp display case. The resulting heat transfer process between the 0F air and the 80F liquid...
  24. No word parsing, as the discussion seemed to be...

    No word parsing, as the discussion seemed to be about subcooling increasing evaporator capacity.

    Regarding the effect of subcooling on overall system efficiency:

    If the subcooling can be...
  25. I'm certainly not right about everything, so I'd...

    I'm certainly not right about everything, so I'd be interested to hear which points you disagree with.
  26. Replies
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    37,502

    The Sporlan C and CP (pressure limiting) and Z...

    The Sporlan C and CP (pressure limiting) and Z and ZP (pressure limiting) are all cross charges.

    The characteristic of a liquid charge, where the fluid in the bulb is the same as the refrigerant...
  27. Replies
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    1,110

    Make sure the controller is set up for the...

    Make sure the controller is set up for the correct brand of EEPR (Sporlan, Emerson, Danfoss), and the correct maximum number of steps that the valve has.

    Also, the controller never really knows...
  28. Replies
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    1,580

    One of the variables in a supermarket is the...

    One of the variables in a supermarket is the difference in liquid temperature resultant to the liquid line running through the case lineup, and being influenced by the return air temperature. A...
  29. Interesting discussion going on here. As many...

    Interesting discussion going on here.

    As many have stated, there is no increase to evaporator efficiency by subcooling the liquid refrigerant. The evaporator doesn't notice any difference when the...
  30. Replies
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    1,536

    Interesting to see your "The primary function of...

    Interesting to see your "The primary function of a design engineer is...."

    Sure, you can guess,and take several sizes with you, but really? Design engineers need system design conditions before...
  31. Replies
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    1,120

    That receiver bypass is there to take advantage...

    That receiver bypass is there to take advantage of natural subcooling occurring in the receiver during lower ambient temperatures. Allowing the subcooled liquid to bypass the receiver (where the...
  32. Thread: R407a

    by bunny
    Replies
    4
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    1,008

    Let's see....you "received" 4 "containers" of...

    Let's see....you "received" 4 "containers" of R-407A? Did they just appear out of the blue?

    You are presumably in the trade, yet you went to Wikipedia to see what R-407A is used for?

    Sounds...
  33. Replies
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    1,085

    Just curious: How did you manage to "cut the...

    Just curious: How did you manage to "cut the valve out" with an ODF distributor? Cut out the feeder tubes too?

    You didn't mention using any flux. If this was a traditional brass distributor,...
  34. Thread: What is this?

    by bunny
    Replies
    13
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    2,563

    If the unit is outdoors, and the cap has been...

    If the unit is outdoors, and the cap has been left off the sightglass, the sun can cause the indicator to discolor too.
  35. Replies
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    2,478

    Question: How many HP does your car engine need...

    Question: How many HP does your car engine need to be to achieve a speed of 60 mph?

    Answer: HP is Irrelevant to the answer.

    In an AC application, the HP per ton ratio will be near 1. A -40F...
  36. It's nearly impossible to determine the exact...

    It's nearly impossible to determine the exact amount of refrigerant in a given system, unless you were the person who originally charged it...and assuming there were no small leaks prior to the large...
  37. Replies
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    While I'm certainly not a fan of micro managers,...

    While I'm certainly not a fan of micro managers, until you've had an opportunity to manage a service department you really can't understand why most contractors have installed GPS systems on their...
  38. Replies
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    766

    Are you meaning using an EEPR to control...

    Are you meaning using an EEPR to control discharge temperature or as a discharge bypass valve to maintain a minimum suction pressure?

    If the latter, yes...it's quite a common application. Look at...
  39. A receiver is a vessel where liquid and vapor...

    A receiver is a vessel where liquid and vapor coexist....hence, it's a saturated condition.

    Given the dynamics of the typical refrigeration cycle, you'll have times when subcooled refrigerant...
  40. Replies
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    6,872

    Two questions I would ask a tech during an...

    Two questions I would ask a tech during an interview (geared more towards a commercial and/or refrigeration tech:

    1 - ask the tech to explain what superheat and sub cooling are, then provide some...
  41. Replies
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    2,622

    Given the set points you described above, are you...

    Given the set points you described above, are you only having this problem during periods when the ambient is below 62F?

    The flooding valves and condenser fan cycling controls need to be set such...
  42. Replies
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    3,691

    I see Ice already covered this, but I happened to...

    I see Ice already covered this, but I happened to respond before reading page 2....

    Oil separator to keep oil return issues to a minimum, EPR valves to maintain temperature with a thermostat and...
  43. Replies
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    1,296

    Also, one single compressor units with long...

    Also, one single compressor units with long piping runs, installing the SV at the receiver outlet might necessitate a larger receiver to prevent high pressure during pump down (if the standard size...
  44. Thread: subcooling

    by bunny
    Replies
    74
    Views
    9,332

    Once the liquid entering the TEV goes through the...

    Once the liquid entering the TEV goes through the expansion process, the exiting liquid/vapor mixture is at the SST corresponding to the evaporator pressure. At this point it's immaterial that the...
  45. Thread: subcooling

    by bunny
    Replies
    74
    Views
    9,332

    Having worked for a manufacturer for nearly 25...

    Having worked for a manufacturer for nearly 25 years I get the concept of occasionally having to make concessions in design to be more competitive in the marketplace. Nothing new there.

    I do take...
  46. Thread: subcooling

    by bunny
    Replies
    74
    Views
    9,332

    A typical supermarket might employ a mechanical...

    A typical supermarket might employ a mechanical subcooler on the Low Temperature rack. Rather than a 90F liquid being supplied to the TEVs, it might now be 50F.

    What does this accomplish? The TEV...
  47. Thread: subcooling

    by bunny
    Replies
    74
    Views
    9,332

    .

    .
  48. Thread: subcooling

    by bunny
    Replies
    74
    Views
    9,332

    I'm going to disagree with this statement....or...

    I'm going to disagree with this statement....or at least offer an interpretation of what you might be saying.

    IT might be splitting hairs, but the heat contained in the liquid refrigerant does not...
  49. Thread: subcooling

    by bunny
    Replies
    74
    Views
    9,332

    The liquid will never be above the condensing...

    The liquid will never be above the condensing temperature. First, you cannot raise a liquid above its saturation (boiling) temperature...it's physically impossible. Secondly, as the liquid travels...
  50. Replies
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    915

    Incidentally, the R-12 valve with a 1 ton...

    Incidentally, the R-12 valve with a 1 ton capacity will be approximately 1.2 tons with R-134A, and approximately 1.3 tons with MP39.

    Not a huge deal on smaller systems. At one time there were a...
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