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  1. #1
    Join Date
    Aug 2009
    Posts
    34

    What do you do when a TXV is hunting?

    What is going on w/ the system when a txv is hunting for correct superheat? I charged a split system w/ a txv to the correct subcooling but checked the superheat and the txv was opening way up and closing going frm 10 to 20 degrees superheat. Would I just have to adjust the txv manually until its correct?

  2. #2
    Join Date
    Jul 2009
    Location
    In a mechanical room....
    Posts
    1,888
    Quote Originally Posted by Groganson View Post
    What is going on w/ the system when a txv is hunting for correct superheat? I charged a split system w/ a txv to the correct subcooling but checked the superheat and the txv was opening way up and closing going frm 10 to 20 degrees superheat. Would I just have to adjust the txv manually until its correct?
    Low load/ dirty evap restricted air flow
    “It takes courage to grow up and turn out to be who you really are.”

    - E.E. Cummings

  3. #3
    Join Date
    Aug 2009
    Posts
    34
    Your right it was reading fine for a couple of hours but the space must have cooled dwn and then there was no load. This site explains it pretty good http://www.achrnews.com/Articles/Ser...00f932a8c0____

  4. #4
    Join Date
    Feb 2007
    Location
    Northern NJ
    Posts
    646
    If it was fine for a couple of hours then started to hunt- the valve is either oversized or your evaporator airflow is restricted. Are you sure there was no frost on the coil?

  5. #5
    Join Date
    Aug 2009
    Posts
    34
    ya it was on a lieberte in a huge server room that they keep super clean and change the filters like once a month. There was a leak in the system and I repaired the leak and was recharging the unit, charged it to subcooling, got correct subcooling then checked the superheat and the unit was at a steady 15 degrees superheat then started going between 10 to 20 degrees hunting and was just wondering if I messed up the charge.

  6. #6
    Join Date
    Apr 2007
    Posts
    177
    Quote Originally Posted by Groganson View Post
    ya it was on a lieberte in a huge server room that they keep super clean and change the filters like once a month. There was a leak in the system and I repaired the leak and was recharging the unit, charged it to subcooling, got correct subcooling then checked the superheat and the unit was at a steady 15 degrees superheat then started going between 10 to 20 degrees hunting and was just wondering if I messed up the charge.
    Is the TXV bulb secure to the sucition line and insulated? you might try changing the bulb placement of the bulb.

  7. #7
    Join Date
    Jul 2009
    Location
    In a mechanical room....
    Posts
    1,888
    If I had to guess you use to have 1000,0000000000,00000000,0000K of heat generated by vacuum tube electronics and since modern technology came by and we use solid state electronics now and produce 10k of heat and they kept that enormous unit. What happens it's under no load and with no load the txv hunts.
    “It takes courage to grow up and turn out to be who you really are.”

    - E.E. Cummings

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