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  1. #1
    Join Date
    Oct 2006
    Posts
    28

    Is it the TXV???

    about 1 year old sys worked 1 summer this is the 2 summer....found sys low 0F subcooling (side glass bubles) added 3 lbs of 410 A (service tech left caps off service valve) sys runs now with 4F of subcooling yes side glass is clear (4F subcooling as per lennox chart) LOW 75PSI HIGH 250PSI 410A SYS i think ambiant was like 80F after added 3lbs of 410a ran sys for 20min check txv superheat by compresor 58F check indoor unit 12 blinks 1200 CFMS(3 ton cond),filter clear,return clear,evap coil clean,freezing right after TXV......remove sencing bulb warm up by hand low said still the same liqud line is same before txv as by the service port....i think i got covered evrything before i go ahead and order new TXV???????
    What i did is added more 410A so i have 25F of superheat overcharge it so custumer has ac until we come back with new one LOW 115PSI HIGH 350PSI you thing i did good thing????
    OTHER QUESTION ONLY FOR PEOPLE WHO WORK BY THE BOOK......
    ON R-22 WHAT SHOULD YOU HAVE SUPERHEAT ADJ???? IS IT 20F by compresor?? and whats TXV for 410a superheat adj??? i have check sys they are running with 30F of superheat (BY COMPRESSOR) with proper subcooling......thanks guys and you hacks dont bother to write answear on this

  2. #2
    Join Date
    Jun 2007
    Location
    Atlanta, GA
    Posts
    56

    huh?

    I don't understand? If it has a txv, why are you concerned about the superheat reading? Did the txv open when you warmed it?If the valve is not opening up than more 410 should not help.

  3. #3
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,192
    sight glass..
    How are you taking subcooling??

  4. #4
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,192
    Why do you think you overcharged it???
    Are you telling us or asking us something here?

  5. #5
    Join Date
    Sep 2007
    Location
    southern IN
    Posts
    527
    If it is the txv you would have had a high subcooling from the start and no bubbles. Then after 4 lbs r-410 you would have a really high subcooling
    The first man gets the pearl, All the second gets is the shell

  6. #6
    Join Date
    Oct 2006
    Posts
    28
    Quote Originally Posted by canesfanforlife View Post
    I don't understand? If it has a txv, why are you concerned about the superheat reading? Did the txv open when you warmed it?If the valve is not opening up than more 410 should not help.
    ......remove sencing bulb warm up by hand low said still the same

  7. #7
    Join Date
    Oct 2006
    Posts
    28
    Quote Originally Posted by d_griff View Post
    sight glass..
    How are you taking subcooling??
    was joking....

  8. #8
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,192
    So... Do you think your starving your evap?? Your TXV not opening?.
    did you do a split?

  9. #9
    Join Date
    Oct 2006
    Posts
    28
    Quote Originally Posted by aruddick View Post
    If it is the txv you would have had a high subcooling from the start and no bubbles. Then after 4 lbs r-410 you would have a really high subcooling
    after 3lbs of 410a sys ran with 4F of subcooling and low side was around 70 psi and high side around 250 psi but sence txv was not oppening not acts like fixed orfice so i didnt want to leave the custumer without A/C over weekend i charge it as orfice superhet then yes i do have high subcooling which at this point doent metter until i replace TXV on monday....and i think my gages are shawing 20F of subcooling if you are wondering

  10. #10
    Join Date
    Oct 2006
    Posts
    28
    Quote Originally Posted by d_griff View Post
    So... Do you think your starving your evap?? Your TXV not opening?.
    did you do a split?
    low

  11. #11
    Join Date
    Sep 2007
    Location
    southern IN
    Posts
    527
    If you had bubbles in the sight glass upon arrival the system was low on ref. I find it interesting that the system was low and has a bad txv
    The first man gets the pearl, All the second gets is the shell

  12. #12
    Join Date
    Oct 2006
    Posts
    28
    Quote Originally Posted by aruddick View Post
    If you had bubbles in the sight glass upon arrival the system was low on ref. I find it interesting that the system was low and has a bad txv
    custumer said that has been freezing up for the past month and he was shuting off to unmelt and then he was putting back on also the previose service tech when he did start and test on the new sys he left the valves caps off lennox seems that has lots of leaks on those service valves i was told that and lots of guys charge by side glass which 410A sys end up been undercharge


    so what do you thing that could be the problem....what else should ive checked???


    bulb must always be colder than the power element or the valve's
    body. If not, the charge can migrate from the bulb to the power element with a resultant loss of control <-----p-i found this on NET

  13. #13
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,134
    Quote Originally Posted by aruddick View Post
    If you had bubbles in the sight glass upon arrival the system was low on ref. I find it interesting that the system was low and has a bad txv
    Residential systems will likely bubble with the correct charge. Never charge a resi system by sight glass.
    Perhaps you should have read the instructions before calling.

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