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  1. #1
    Join Date
    Aug 2015
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    York R410 residential split not cooling (gas pressures not correct)

    Hello fellow HVAC dudes and dudettes,
    I got a puzzle thats been bugging me for a few nights now and decided to ask you all fine people for your input.
    I have some York model YHJD36S41S4A units that are not working right. They are not cooling correctly. The size should be a little over for the space being cooled, but temperature can only be maintained in the high 70`s (75-79) and the unit will never cycle off and runs constantly.
    When checking the gas the pressures are not adding up and adding / removing gas dont seem to do help at all.
    Utilizing the chargeing chart on the unit, it shows how to charge by utilizing outside DB F, Suction temp, and suction presure. The outside DB is 93 F, next is suction pressure (120psi), this does not even make it on the charts because the temperature is so low. next is the suction temperature which is 68 F, this correlates with a 154psi suction pressure.
    The high side is 320psi, adding charge only increases high side pressure and does nothing for the suction.
    Recovered the whole charge and added fresh gas (liquid of course), charged to manufacture weight, plus added gas as recomended for line run of 20`(over 15`). Now the charge is at 110 suction and 280 high side.
    Now I did not install these units, but I have more than one on differant facilities and a lot of them are acting the same (all installed by same contractor). Going back to contractor is not an answer so I am left to find out whats going on. Any ideas??
    Coil is clean, filter is clean, new installs. Matched air handling equipment is York MA14DN21H for coil unit and FC48D3XC1A for the Air Section.
    I usually would consider myself a decent A/C tech, but this one has got me a little confused. I would appreciate any input or sugestions.
    Thanks!!

  2. #2
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
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    what is the metering device ,what is the subcooling and superheat

  3. #3
    Join Date
    Aug 2015
    Posts
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    Superheat is 33 degrees give or take (r410, suction temp of 68, pressure of 120/110), subcooling I could not get but would imagine around 5 degrees (temp gauge wouldnt read it clearly but close to 100F and 320 psi on high side). There are 2 metering devices, one on the evaporator (verified), and an orifice on the condenser (supposidly). I wrote down the evap TXV but will need to bring that to the forum later as I cant seem to locate it at the moment.

  4. #4
    Join Date
    Dec 2005
    Location
    Cleveland, OH
    Posts
    3,490
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    You may have a sticky evap TXV.
    Good? Bad? I'm the guy with the gun.

    Statements made by me are strictly my opinions and do not reflect the opinions of my employer. I am not authorized to make any official statements on behalf of my employer.
    Any technical advice offered by me is for educational purposes only, all HVAC related repairs should only be attempted by qualified personnel.

  5. #5
    Join Date
    Aug 2015
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    We changed out one of the TXV`s on the evap coil and are still having the same issue.

  6. #6
    Join Date
    Aug 2015
    Posts
    11
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    sorry, should have noted what was done so far. So far on one unit we have changed out an Evap TXV, removed all gas, replaced with fresh gas, and changed out the thermostat for good mesure. Fans are all running in the correct direction and all filters are clean.

  7. #7
    Join Date
    Feb 2010
    Location
    Lebanon, PA
    Posts
    21
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    When you recovered, how much did you get?

    What is your sub-cooling?

    When you weighed the charge back in did you add the extra charge for the txv, as specified?


    Sent from my iPhone using Tapatalk

  8. #8
    Join Date
    Jul 2010
    Location
    nebraska
    Posts
    1,651
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    Measure your air flow.

  9. Likes BALloyd liked this post.
  10. #9
    Join Date
    Mar 2012
    Location
    North Vernon, Indiana
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    How old are these systems?

  11. #10
    Join Date
    Feb 2010
    Location
    Lebanon, PA
    Posts
    21
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    Quote Originally Posted by martyinlincoln View Post
    Measure your air flow.
    That's your first step. If these systems were never properly commissioned, you could be moving 1400 to 1600 cfm. Get the airflow set, then look at your charge.


    Sent from my iPhone using Tapatalk

  12. #11
    Join Date
    Jan 2010
    Location
    Vancouver Island
    Posts
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    Quote Originally Posted by martyinlincoln View Post
    Measure your air flow.
    X3

  13. #12
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    10,468
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    All of the numbers you posted sound fairly good except for the SH. York TXVs are usually set at somewhere in the 10-12* range and sub cooling in the 7-11 range. I thinks it's low on gas. A lot of the matches are +20 ounces for the evaporator. Airflow may be a little high too, but I bet the ductwork is less than stellar.

  14. #13
    Join Date
    Nov 2010
    Location
    Andover Kansas
    Posts
    2,335
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    OP-
    Going by the info you posted:
    With your indoor DB and OD DB:
    Your Head is low
    your suction is low
    Your subcool is low
    your Superheat is high
    --At this points towards being low on charge
    *disclaimer-If the readings you posted are wrong, then my diagnosis is wrong as well.

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