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  1. Replies
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    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...
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    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...
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    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...
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    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...
  5. Thread: subcooling

    by bunny
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    3,298

    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...
  6. Thread: subcooling

    by bunny
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    3,298

    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...
  7. Thread: subcooling

    by bunny
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    3,298

    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...
  8. Thread: subcooling

    by bunny
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    3,298

    .

    .
  9. Thread: subcooling

    by bunny
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    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...
  10. Thread: subcooling

    by bunny
    Replies
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    3,298

    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...
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    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...
  12. Thread: Cleaning out TEV

    by bunny
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    Agree that on smaller TEVs it's probably more...

    Agree that on smaller TEVs it's probably more cost effective to replace. When doing so I highly recommend disassembling the old TEV so as to determine what was strong with it.

    If its a...
  13. Thread: Cleaning out TEV

    by bunny
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    Any TEV that can be dissembled can be cleaned...

    Any TEV that can be dissembled can be cleaned out.

    Use a Virginia or Calgon solvent to clean all of the parts and the interior of the body, then blow it out with CO2 and reassemble.
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    One of the shortfalls with mechanical HGB in a...

    One of the shortfalls with mechanical HGB in a comfort cooling application is that you're trying to prevent the evaporator (or chiller barrel) from operating at a temperature that would cause freeze...
  15. Thread: "Drying" a drier

    by bunny
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    1,217

    The standard core has a higher acid capacity then...

    The standard core has a higher acid capacity then the HH core...but not by much.

    The HH core was developed to remove wax like contaminants (not parifin) in LT R-22 and R-502 systems. It's not an...
  16. Thread: "Drying" a drier

    by bunny
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    The process of heating dessicant as a means of...

    The process of heating dessicant as a means of driving moisture out of it is called reactivation.

    Having worked at the valve company in question.....reactivating cores is possible....but not...
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    Pilot operated solenoid valves require a minimum...

    Pilot operated solenoid valves require a minimum amount of pressure drop to close. If they're oversized, there might not be enough pressure drop to move the disc when the coil is de-energized.

    An...
  18. Excerpt from DoPont "Retrofit Guidelines for Suva...

    Excerpt from DoPont "Retrofit Guidelines for Suva Refrigerants"

    R-12, R-22 and SuvaŽ 134a are all single component refrigerants with no temperature “glide” in the evaporator or condenser. SuvaŽ...
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    Ammonia systems are interesting....but few...

    Ammonia systems are interesting....but few compared to non-ammonia systems.

    As others have stated, plan on a lot of travel.

    Or find a company that does both.
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    Hopefully you understand that cap tubes or...

    Hopefully you understand that cap tubes or flow-raters don't offer the performance a TEV does.

    They're sized to operate at design superheat at a specific design condition. Anything outside of the...
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    Actually, many OEMs want their TEVs factory set...

    Actually, many OEMs want their TEVs factory set according to their specification, but also don't want technicians to have the ability to change that factory adjustment.

    This valve satisfies both...
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    The O valve is a balanced ported valve and can...

    The O valve is a balanced ported valve and can throttle down to approximately 25% of its nominal capacity.

    That being said, it's still a curious application....probably budget took precedence over...
  23. Thread: Dallas

    by bunny
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    For good Tex-Mex...Pappasito's

    For good Tex-Mex...Pappasito's
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    2-3 is pretty low considering there is some...

    2-3 is pretty low considering there is some margin of error in the gauges and temperature meter. Plus, the SH you're reading on the outside of the pipe is not the true SH of the refrigerant inside...
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    I Worked for " the" valve company, and never...

    I Worked for " the" valve company, and never heard anyone say to size the TEV for 65% of rated capacity.

    Many of the commercial R410-A systems with micro channel condensers are using TEVs with...
  26. It would be a tax deductible expense, just as...

    It would be a tax deductible expense, just as tools are.
  27. Thread: Why.....

    by bunny
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    That's easy....they were either left over from a...

    That's easy....they were either left over from a commercial job or bought at a salvage sale.
  28. Thread: 407A gas

    by bunny
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    R-407A is becoming quite popular here in the US....

    R-407A is becoming quite popular here in the US. I'd say 40%+ of all new equipment being built for supermarkets is using 407A...and probably 90% of the R-22 conversions are going with R-407A. There...
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    Obvious insight would be to look for the simple...

    Obvious insight would be to look for the simple causes to problems first.
  30. Thread: txv selection?

    by bunny
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    The only things required to select a TEV are SST,...

    The only things required to select a TEV are SST, liquid temperature and pressure drop across the TEV port.

    Ratio of nozzle size to TEV...not sure what you're meaning by that. The only factor the...
  31. Thread: txv selection?

    by bunny
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    Since it is near impossible to find a compressor...

    Since it is near impossible to find a compressor with the exact capacity of the evaporator, or in your case the exact capacity of the three evaporators piped to the compressor, it's best to size the...
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    Never a good idea to select a solenoid valve...

    Never a good idea to select a solenoid valve based on line size. The ME10 has a nominal capacity of 11 tons. A valve that is oversized may not have enough pressure drop through the port to allow th...
  33. Thread: txv selection?

    by bunny
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    It's best not to generalize when selecting...

    It's best not to generalize when selecting components. Go to the TEV selection chart and select a valve based on your system conditions.

    The three things that affect TEV capacity ar Evap...
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    Nice touch with the video. Long story on the...

    Nice touch with the video.

    Long story on the move....come on by some day and I'll tell you all about it.
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    Glad the problems seemed to have been solved. ...

    Glad the problems seemed to have been solved.

    You mentioned that the original Turboshed separator used 2 Y-825 valves to reduce the oil pressure from the separator; one for the LT and one for the...
  36. You guys are brutal....but not without cause. ...

    You guys are brutal....but not without cause.

    :cheers:
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    That was for the ice rink.

    That was for the ice rink.
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    Enlighten us regarding residual refrigeration.

    Enlighten us regarding residual refrigeration.
  39. Replies
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    Thanks for the explanation Kingvalve. That's a...

    Thanks for the explanation Kingvalve.

    That's a direct drive DC Synchronous motor...another evidence of the age of this machine.

    Carbondale was made my Worthington.
  40. Replies
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    Parts changers assume. Technicians study out the...

    Parts changers assume. Technicians study out the problem and make an educated analysis based upon the facts, the system conditions, an understanding of refrigeration principles and an equal...
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    I think you just told us what your problem is. ...

    I think you just told us what your problem is.

    Now find out why you've got high superheat, and then you'll be on your way to a solution.
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    You say the TEV is working fine, but I've not...

    You say the TEV is working fine, but I've not seen any mention of superheat.

    While sludge in the evaporator certainly could be the cause, it is likely way down near the bottom of the list of...
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    Blast from the Past

    I used to work for Hussmann in San Jose, CA. One day I called dispatch to get the next service call of the day, and there were a few "plugged drain" and other boring calls pending, so I asked what...
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    Here's a real blast from the past....similar to...

    Here's a real blast from the past....similar to what was mentioned in the previous post.

    I'll post some additional photos in the Wall of Pride section, but here's a teaser.
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    Now it all makes sense. Now, don't...

    Now it all makes sense. Now, don't misunderstand...I'm not denigrating the plumbing profession.

    You're asking about the function and intricate details of operation of the human heart, but you...
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    While the price is tough to accept, it's best to...

    While the price is tough to accept, it's best to go with the factory seal. There are different grades of neoprene....a lot of compatibility testing takes place before selecting a seal, and you'd hate...
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    Wowza....I'm getting old. Time to retire and...

    Wowza....I'm getting old.

    Time to retire and let Obama take care of me!
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    That's true, but the valve doesn't see or respond...

    That's true, but the valve doesn't see or respond to what's happening on the discharge side. All it can do is limit the pressure at its outlet, regardless of what the discharge pressure is.
    ...
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    The drawback of the pressure limiting charge is...

    The drawback of the pressure limiting charge is this:

    After the defrost cycle, the pressure between the outlet of the TEV and the inlet of the compressor might be excessive (particularly on...
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    The CPR does not care about compression ratio....

    The CPR does not care about compression ratio. It's sole purpose is to prevent the compressor suction pressure from rising to a point where it would result in compressor motor overload.
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