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  1. #14
    Join Date
    Sep 2008
    Location
    Western PA
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    25,545
    Quote Originally Posted by mwright View Post
    Yes between the compressor and the condenser coil but closer to the coil. Am I supposed to Benin the other side of the coil, the output side?

    Incase you haven't figured it out I'm new to this and I appreciate all the help. Where I work doesn't have anyone with the time to train me so I'm digging in and learning as I go. :-)
    Yes.


    Measure subcooling on the outlet of the condenser, not the inlet.

    What you were measuring was discharge superheat and, actually, that figure is a bit too low, IMO.

    I'll be curious to see the actual subcooling.
    Last edited by jpsmith1cm; 03-31-2012 at 05:11 PM. Reason: brain f**t

  2. #15
    Join Date
    Feb 2012
    Location
    Savannah, NY
    Posts
    82
    Quote Originally Posted by jpsmith1cm View Post

    I'll be curious to see the actual subcooling.
    Unfortunately I won't be able to get that until Monday. I will post as soon as I do.

  3. #16
    Join Date
    Feb 2008
    Location
    California
    Posts
    2,065
    Does this thing have a Receiver and liquid line sight glass?

    If so

    You can forget all about that confusing subcooling

  4. #17
    Join Date
    Feb 2012
    Location
    Savannah, NY
    Posts
    82
    Yes is does have a receiver but no sight glass.

  5. #18
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    Sep 2008
    Location
    Western PA
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    Quote Originally Posted by mwright View Post
    Yes is does have a receiver but no sight glass.
    Install one.

    Once you put a receiver on a system, you don't need to worry about subcooling, you need to worry about a clear sightglass.


    My mistake for not catching this earlier. I'm switching to AC mode and subcooling is part and parcel of that.

    I'll take myself out back and whip myself 25 times with a refrigerant hose, now.

  6. #19
    Join Date
    Sep 2005
    Location
    florida
    Posts
    5,503
    Quote Originally Posted by jpsmith1cm View Post


    How ya been, Cracker?
    Howdy jp.
    I love the smell of phosgene first thing in the morning:

    To apply for professional membership click here


    Educational forums are open.

    If you would like to submit a link or an article or other related info to the EF. click here

  7. #20
    Join Date
    Sep 2005
    Location
    florida
    Posts
    5,503
    Quote Originally Posted by jpsmith1cm View Post
    Install one.

    Once you put a receiver on a system, you don't need to worry about subcooling, you need to worry about a clear sightglass.


    My mistake for not catching this earlier. I'm switching to AC mode and subcooling is part and parcel of that.

    I'll take myself out back and whip myself 25 times with a refrigerant hose, now.


    I'll furnish the hose.
    I love the smell of phosgene first thing in the morning:

    To apply for professional membership click here


    Educational forums are open.

    If you would like to submit a link or an article or other related info to the EF. click here

  8. #21
    Join Date
    Feb 2012
    Location
    Savannah, NY
    Posts
    82
    So you are saying that
    If there is a receiver there is no need to worry about Sub cooling? If so why is that? Also I should put in a sight glass, charge with correct amount of refrigerant and if sight glass is clear I'm good to go?

  9. #22
    Join Date
    Sep 2008
    Location
    Western PA
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    Quote Originally Posted by mwright View Post
    So you are saying that
    If there is a receiver there is no need to worry about Sub cooling? If so why is that? Also I should put in a sight glass, charge with correct amount of refrigerant and if sight glass is clear I'm good to go?
    Yep, that's about the size of it.

    Subcooling is what it is and only massively overcharging the unit will make it change.



    That, of course, assumes that you've got a functional metering device.

    Strike the balance and you're golden.

  10. #23
    Join Date
    Feb 2012
    Location
    Savannah, NY
    Posts
    82
    New readings for today
    Low side is running around 40
    High side around 280
    SH 11 at Evaporator
    Pressure gauge set at 42 & 82 or close
    Case is running at about 37 deg.
    Shutting off at 37psi and turning on at 72psi according to my AK900
    Pressures are off on the pressure switch!

  11. #24
    Join Date
    Feb 2012
    Location
    Savannah, NY
    Posts
    82
    I readjusted pressure switch and it comes on at 81.7 psi and shuts off at 42.4.
    When I read the SH when should I take the true reading? As the compressor is shutting down?

    Case has been running about hour and a half now. Seems to be holding temp at 38 deg. Would like it to hold at about 41.
    There's some frost forming at the TXV and towards the coil but not freezing up.

  12. #25
    Join Date
    Feb 2012
    Location
    Savannah, NY
    Posts
    82
    Running about 3 hours now.
    Changed pressure settings, cut out at 42.2 and cut in at 84.8
    Holding right around 40 deg.
    Still frost by TXV but no ice
    SH is about 15 when the compressor cuts out.
    I'm thinking it may have been cycling too often which made the TXV freeze. Is that a logical explanation?

  13. #26
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,545
    Quote Originally Posted by mwright View Post
    New readings for today
    Low side is running around 40
    High side around 280
    SH 11 at Evaporator
    Pressure gauge set at 42 & 82 or close
    Case is running at about 37 deg.
    Shutting off at 37psi and turning on at 72psi according to my AK900
    Pressures are off on the pressure switch!
    Pressure switch scales are almost NEVER accurate. You must set them with an accurate gauge as you did.

    Quote Originally Posted by mwright View Post
    Running about 3 hours now.
    Changed pressure settings, cut out at 42.2 and cut in at 84.8
    Holding right around 40 deg.
    Still frost by TXV but no ice
    SH is about 15 when the compressor cuts out.
    I'm thinking it may have been cycling too often which made the TXV freeze. Is that a logical explanation?
    Why do you have a problem with frost at the TEV?

    You've got a coil that is below freezing. Frost is an inevitibility. This is why we have a DE-FROST cycle.

    IMO, 40 degrees is too warm for most medium temp applications. You need the product to remain below 40 degrees. To achieve that, you need to get that thing colder. Without knowing what product you're dealing with, I'm typically shooting for a high-20s, low-30s target for cutout.


    Sounds like you've about got it whipped, though.

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