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  1. #1
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478

    Walk In Freezer Woes

    Brand new condenser and evap. 404a. Fired up and ran great. Hot box. Opened txv up a few turns... SH was way high.

    Leave and go back next morning to set SH and check everything out. Box was at 8 degrees, 10 deg SC, 25 deg Sh at the bulb and around 40 at the compressor. Cool, I need to open the txv. Half a turn and no change in SH. Another half a turn and so on. Before I know it stem is back seated. Still 20 deg SH. WTF.

    Call the "expert" who sized and sold me the equipment. He said for the box size and load and equipment btu rating I should have to be squeezing the txv closed, not opening. I tell him that goes against logic, to get my superheat down I need to open it. He says if I went to far I could be overfeeding the evap and he agrees with my logic but it is "one of those refrigeration phenoms". Tells me to take it back to mid point, leave and let it settle down, and come back and check. Im about to head that way and see how its doing.

    Would love to hear thoughts from you experts

  2. #2
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    To add. The loops are all nicely frosted except the top couple. Everything, IMO, points to the fact that the evap isnt flooded. Am I wrong in my thinking?

  3. #3
    Join Date
    May 2004
    Posts
    12,280
    Just a thought if you want to concentrate on the TXV... are you sure you opened the valve?

    Some valves turn CW while others turn CCW to open it up.

    Another thing... are there aeroquip fittings on the condenser and or evap coil?

  4. #4
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    Well to find my midpoint i closed the txv all the way down and my suction went to almost 0. Counted turns to get it all the way open then half as many turns clockwise to get it in the middle. So i do believe clockwise closes it down.

    Not sure what aeroquip fittings are? It was all brazed in

  5. #5
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    gotta run heres the numbers.

    condenser - fjal-b301-tfc-o15-copc

    evap - lce6-94bb-lark

    txv- sqe body-spoe

    head - kt-43-sz-spop

    cartridge - qc-3-spop

  6. #6
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    One more thing before I run. After finding the midpoint my suction temp at the evap suction line was lower than when the valve was fully open. Maybe the "phenom" he mentions has merit?

  7. #7
    Join Date
    Oct 2011
    Location
    Hull
    Posts
    53
    With25sh it's sure you are not flooding evap. I hope to have the explication of that phenom!

  8. #8
    Join Date
    Feb 2010
    Location
    NE Alabama
    Posts
    301
    Is the system going through the fan delay cycle to prechill evaporator.

  9. #9
    Join Date
    Feb 2010
    Location
    NE Alabama
    Posts
    301
    Also, if you're starting with a hot box it could take a couple of days to cool off the floor and the box, and you might need a defrost on arrival to start checking superheat. I've had freezers that took three days to cool things off enough to adjust the txv correctly.

  10. #10
    Join Date
    Feb 2006
    Location
    USA
    Posts
    4,381
    Quote Originally Posted by crymtide View Post
    Also, if you're starting with a hot box it could take a couple of days to cool off the floor and the box, and you might need a defrost on arrival to start checking superheat. I've had freezers that took three days to cool things off enough to adjust the txv correctly.
    I agree about waiting to adjust the txv. 3 days sucks lol but I've waited out overnight. Constantly reading threads here will lead me never to forget that waiting time. I've chased my own a$$ a few times in my early days with hot pull down n attempting to fine tune

  11. #11
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    Wasnt a complete hot pull down. Food was still frozen when we started the new one up.

    Got there this morning and box was at 5 deg with 25 deg SH. The txv is not feeding correctly. Half a turn...no change. Another half a turn...no change. 3 full turns and i get a couple degrees movement. Evap will not flood.

    I realize a hot pull down requires some time but Ive never had a new TXV that was so unresponsive, even with a warm box. With the matchup I have I should be having to squeeze the valve down, not opening it up.

    Fan delay works fine. Defrost works fine. Evap is clear.

    Picked up a new valve today and will start digging in the morning starting with pulling the bulb and warming it. Didnt bother today.... would have been useless since I didnt have the parts to do anything with it.

  12. #12
    Join Date
    Sep 2005
    Location
    florida
    Posts
    5,514
    Just a thought I once had coil we ordered fore R-22 but it was shipped with a 404 orifice in it drove us crazy.
    I love the smell of phosgene first thing in the morning:

    To apply for professional membership click here


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  13. #13
    Join Date
    Feb 2010
    Location
    NE Alabama
    Posts
    301
    Is your txv bulb vertical or at 4 or 8 o'clock and is it insulated?

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