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  1. #1
    Join Date
    Sep 2005
    Location
    ohio
    Posts
    16


    We are adjusting a TXV on a walk-in frezer. The superheat was high. The charge is fine. It is an R-22 system. We were told if we turned the stem on the TXV clockwise this would increase the superheat and counter clockwise would decrease the superheat. Is this correct. We were also told to go 1/4 turn at a time and let the system run for 10 minutes or so. Also, how long should it take to dial it in? I have not done this before, and it seems it is taking forever. Any help would be appreciated

  2. #2
    Join Date
    Feb 2006
    Posts
    114
    As far as turning the adjudtment stem on the TXV, that is correct, but R-22 is not the most desirable refrigerant for freezer applications, especially with the plethora of available refirgerants on the market today. I'd much rather see r-404a used for a freezer, but that's just me, I'm sure a lot of folks have their own favorite for various reasons.

  3. #3
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,327

    R22 Freezer TEV......

    Yes, you were told correctly. If after adjust CCW a bit if there's no response from the valve with lower SH check for adequate subcooling before the valve. If that's OK check and clean the valve's inlet screen if necessary. If that doesn't work you likely need a more valve capacity, ie a bigger valve.

    Also, be sure the box is close to proper temperature before adjusting the valve.

    As far as how long does it take......it takes as long as it takes. Be patient and look busy.

  4. #4
    Join Date
    Feb 2004
    Location
    Medford Oregon
    Posts
    807
    the answer on how to adjust are correct but real
    question should be why are you adjusting the valve
    what problem were you trying to solve

    you will probably get more valid answers if this
    info was given

    PS: I agree R404A should be you LT of choice
    you will get more capacity and less problems
    check if you unit is dual rated (R22 & R404A)


  5. #5
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,327
    Originally posted by rocket
    the answer on how to adjust are correct but real
    question should be why are you adjusting the valve
    what problem were you trying to solve

    you will probably get more valid answers if this
    info was given
    Good point. The OP said however that the SH was high so that's what I went with in my reply. Usually all we get for info is that it's not pulling down to temp and they have no clue as to why.

  6. #6
    Join Date
    Feb 2004
    Location
    Medford Oregon
    Posts
    807
    superheat was high
    what was it, did you measure it

    very often high superheat is an overheating problem
    adjusting TXV no value there

  7. #7
    Join Date
    Feb 2006
    Location
    Austin, Texas
    Posts
    341
    Don't waste your time and the customer's money playing with the superheat setting. If the charge and compressor are working fine your are going to end up replacing the valve anyway. Just replace the valve and filter/drier. Be done with it and walk away. Sporland factory setting is mid range. Go all the in, all the way out, then back to mid range. I don't remimber but I think it was 16 turns, maybe 8?

  8. #8
    Join Date
    Sep 2005
    Location
    ohio
    Posts
    16


    It is an old walk-in that we rewired and charged. At the time we walked up on it, we were told nobody was sure if it even worked. We got it going and were getting a superheat of 22 or 23. It seemed to be taking so much time that I thought of just changing out the TXV to save both time and money. We started checking the SH before the box got down to temp. Thanks for the input.

  9. #9
    Originally posted by rickl
    Don't waste your time and the customer's money playing with the superheat setting. If the charge and compressor are working fine your are going to end up replacing the valve anyway. Just replace the valve and filter/drier. Be done with it and walk away. Sporland factory setting is mid range. Go all the in, all the way out, then back to mid range. I don't remimber but I think it was 16 turns, maybe 8?

    hey rickl it is 8 full turns from closed to open, leaving valve at factory setting of mid seated at 4 turns. and i was also told 15 minute wait per 1/4 turn

  10. #10
    Join Date
    Feb 2006
    Location
    Austin, Texas
    Posts
    341
    thanks Mrfreez. your a good man. just haven't done it in along time

  11. #11
    Join Date
    Feb 2004
    Location
    Medford Oregon
    Posts
    807
    if your cooler was off for a long time, it will
    take a long time to pull the heat out of those
    walls. just ask guys who install new boxes. 24 to 36
    hrs is the least to expect

    adjusting superheat during this heavy load
    pulldown is foolish, wait until close to desired
    box temp then check superheat. more than likely
    no adj is needed

  12. #12
    Join Date
    Jan 2006
    Posts
    129
    You will have a tough time trying to set the valve during a warm pull down.

  13. #13
    you have to adjust the subcooling to determine how to adjust txv. guage both the subcooling and superheat. just adjusting the txv for superheat is going to cause major problems.

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