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  1. #40
    Join Date
    May 2004
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    11,999

  2. #41
    Join Date
    Jan 2007
    Location
    maine
    Posts
    788
    Had a similar case do this to a tech at my old company.. Did exactly what you did and nothing..If i were you before you do anything i would do a performance curve. but i would ave the tx and nozzle with me

  3. #42
    Join Date
    Jun 2012
    Location
    Daytona Beach, FL
    Posts
    11
    Just a thought here but have you checked your king valves? I have found in the past where someone has metered the vapor or the liquid line using the back seated king valves. When the almost identical situation happened to me I had to back the valves all the way out and then turn them back in about a 1/4 to a 1/2 turn and presto ... My problem was solved. Another time I found the liquid line dryer restricted. Since it is a 404A system it so more than likely using POE oil which will flat out suck up the moisture if it is exposed to the atmosphere thus I always change the oil and liquid line dryer out on 404A systems anytime I have them open. A little moisture can sure produce some strange SH & SC measurements.

  4. #43
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    Quote Originally Posted by Bobbycold View Post
    I might have just missed the discharge pressure, but when I change an evaporator, before I get to the fine tune stuff, I use the suction and discharge pressures to set the TXV to pretty close. I also use the scale (mainly to know that I honestly am charging out the right amount of freon), which gives me great confidence that the numbers on my gages do not reflect overcharge or undercharge. If the discharge is high while the suction is dropping, I'm sure you can see where I'm going with this. Depending on the size of the walk in freezer, I may not get to setting the superheat for a few days, yet if I have the correct amount of refrigerant and good suction and discharge pressure, I'm usually pretty close. When setting the rough TXV adjustments, on the occasions that any are required, they are based heavily on the suction and discharge pressure. I am assuming that this walk in has it's own compressor and is not a split type with multiple TXV's, such as a cooler freezer combo.

    I hope that I didn't come across as aggresive. This is my first post
    Charge is fine. My problems are as I listed.

    I generally dont start cranking on the stem upon start up. My SH was dangerously high at the compressor. I guess your personal attacks were edited out. PM me Id love to a chance to retort....

  5. #44
    Join Date
    Jun 2012
    Location
    Tenn
    Posts
    139
    Nothing was edited out. I merely wondered why you adusted the TXV so early. When I initially start a walk in after replacing an evap. I usually simply verify the suction and discharge pressures until it's run a while. There is no personal attack. Something just stuck out that maybe your discharge was high, and you felt it was a TXV that wasn't openning enough, but I didn't see any mention of what the discharge pressure was. Since adjusting the super heat is a small adjustment that I usually make after the rest of the system is stabilized, I was left wondering why you were adjusting the TXV. I have often replaced the evap, and never had to adjust the TXV. The reason I hoped that you wouldn't feel I was being aggresive is because it is possible that what I am saying could come across as condesending and I accept that you must have had a good reason to start adjusting the TXV that early. The super heat would come up later, and if suction and discharge pressures are good should be very close. That's it. Nothing against you either as a person or as a tech. BTW, If I feared that liquid may be getting to the compressor I would have shut the TXV slightly to reduce the amount of liquid entering the evap. This would cause more liquid to flash off in the evaporator and tail and reduce the chance of liquid returning to the compressor.

  6. #45
    Join Date
    Oct 2002
    Location
    Lexington, NC
    Posts
    5,144
    It sounds to me like the orifice is too small and the power head is wide open because he has the same SH at all different box temps. That would account for it not adjusting any with the bulb in hand because it was already wide open.

    Bobbycold, don't worry about offending others because you will. Grow some thicker skin and keep truckin.
    The main thing is to keep the main thing the main thing!

    If "the grass is greener on the other side", it likely has been fertilized with Bull$hit!

  7. #46
    Join Date
    Mar 2007
    Location
    NW AR
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    2,478
    Quote Originally Posted by Bobbycold View Post
    Nothing was edited out. I merely wondered why you adusted the TXV so early. When I initially start a walk in after replacing an evap. I usually simply verify the suction and discharge pressures until it's run a while. There is no personal attack. Something just stuck out that maybe your discharge was high, and you felt it was a TXV that wasn't openning enough, but I didn't see any mention of what the discharge pressure was. Since adjusting the super heat is a small adjustment that I usually make after the rest of the system is stabilized, I was left wondering why you were adjusting the TXV. I have often replaced the evap, and never had to adjust the TXV. The reason I hoped that you wouldn't feel I was being aggresive is because it is possible that what I am saying could come across as condesending and I accept that you must have had a good reason to start adjusting the TXV that early. The super heat would come up later, and if suction and discharge pressures are good should be very close. That's it. Nothing against you either as a person or as a tech. BTW, If I feared that liquid may be getting to the compressor I would have shut the TXV slightly to reduce the amount of liquid entering the evap. This would cause more liquid to flash off in the evaporator and tail and reduce the chance of liquid returning to the compressor.
    Sorry, Dads comment about the personal slap got me to wondering. It was cool the day of the install. About 75 if i recall correctly. The head was running around 225...i think. Its been almost a week. Slugging is always a paramount concern but the SH at the comp was so high, even after the box was below freezing, it was disturbing, hence my rush to adjustment.

  8. #47
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    Quote Originally Posted by nchvac View Post
    It sounds to me like the orifice is too small and the power head is wide open because he has the same SH at all different box temps. That would account for it not adjusting any with the bulb in hand because it was already wide open.

    Bobbycold, don't worry about offending others because you will. Grow some thicker skin and keep truckin.
    It did open when i warmed it. Suction rose and suction line temp shot into the negatives almost instantly. The line wont get below 4 or 5 degrees while mounted. Seemss like a partially charged head like ice stated. Will find out tomorrow or possibly today, if my changeout goes smoothly

  9. #48
    Join Date
    May 2004
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    11,999

  10. #49
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    lol. it IS 3 phase

  11. #50
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,350
    Quote Originally Posted by Dad View Post
    I think I know what the issue is.

    Your incoming voltage is running backwards and the refrigerant isn't a virgin anymore.

    What ya think? .... go fix that thang so we know what's going on.
    Let me see if I following this.

    We have refrigerant that is no longer a virgin, some bad head, and an orifice that is too small.

    I have the answer.


    The unit is 12.
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  12. #51
    Join Date
    Sep 2005
    Location
    florida
    Posts
    5,506
    Quote Originally Posted by timebuilder View Post
    Let me see if I following this.

    We have refrigerant that is no longer a virgin, some bad head, and an orifice that is too small.

    I have the answer.


    The unit is 12.


    Witty comment with held.
    I love the smell of phosgene first thing in the morning:

    To apply for professional membership click here


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  13. #52
    Join Date
    Mar 2007
    Location
    NW AR
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    2,478
    Quote Originally Posted by timebuilder View Post
    Let me see if I following this.

    We have refrigerant that is no longer a virgin, some bad head, and an orifice that is too small.

    I have the answer.


    The unit is 12.
    LOL! Thats wrong TB.

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