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  1. #1
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191

    Compressor flooding

    I have a walk in box, Went to job yesterday found compressor flooding. Check to make sure evap was clean and fan going right way, all good. Tried to adjust expansion valve and nothing!! Went back today put in new valve and same thing, still flooding. Is it possible my new expansion valve is bad ??? It's an old R-12 system that has 414b in it now. It seems that refrigerant is just blowing by the valve, I cant even clear the sight glass, no matter how much refrigerant I put in. Am I missing anything?

    High side pressure was about 112 and low side was about 38. Ambient temp about 64

  2. #2
    Join Date
    Apr 2010
    Location
    San Diego, CA
    Posts
    219
    Sure that compressor is pumping efficiently?

  3. #3
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,718
    Quote Originally Posted by cmclifton View Post
    Sure that compressor is pumping efficiently?
    I'm not the only one who caught that...

    How about a full set of system readings?

    Ambient temp, suction and liquid pressures and "flooding" aren't even close to enough to help you with this system.

  4. #4
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191
    Quote Originally Posted by cmclifton View Post
    Sure that compressor is pumping efficiently?

    If the compressor was in efficient it would be hot or at least warm, not a ball of ice, correct? I did check liquid and suction line temps, don't remeber exactly what they were, but according to pt chart I had no superheat, and about 15degrees of sub cooling if that helps. and the box will not come down in temp at all, so I basically am not getting any heat transfer across evap at all.

  5. #5
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,718
    Your low side was 38 pounds which equals 47 degrees and you compressor was "a ball of ice"?


    Something is very fishy here.

  6. #6
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191
    Quote Originally Posted by jpsmith1cm View Post
    Your low side was 38 pounds which equals 47 degrees and you compressor was "a ball of ice"?


    Something is very fishy here.
    Your assuming SaT. vapor, but if I'm flooding wouldn't that be sat. liquid? then the temp is 32degrees. Now evn though I was flooding I didn't have a clear liquid line sightglass, so I did add some refrigerant to see what would happen and my pressur did increase there for so did the suction temp, but originally my suction temp was about 25 degrees when it was icing up

  7. #7
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191
    there is no heat exchanger and there is no external equilizer.

    Trust me I've been doing this for a long time and I'm just as confused as you guys. I know i doesn't make much sense, just looking for Ideas, because this has me stumped as of right now. I'll be back there this weekend. First thing I'm doing is taking entire charge out and re-charging to make sure charge is proper (I did a lot of adding and pulling of charge when I was there the other night) then I'll take full set of readings.

  8. #8
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,718
    Quote Originally Posted by fr420 View Post
    Your assuming SaT. vapor, but if I'm flooding wouldn't that be sat. liquid? then the temp is 32degrees. Now evn though I was flooding I didn't have a clear liquid line sightglass, so I did add some refrigerant to see what would happen and my pressur did increase there for so did the suction temp, but originally my suction temp was about 25 degrees when it was icing up

    So, you're now claiming a subcooled suction line?

    32F SCT (this is wrong, but I'll play along) with a 25 degree suction line?

    5 degrees suction subcooling?



    Your readings are wrong, friend.



    icexprt,

    I've seen suction/liquid heat exchangers blow out and leak through. Not very common to see that particular part on smaller equipment like this.

  9. #9
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,596
    Assuming you have the bulb in the right place and insulated well? We do need some numbers to look at. Also does this have some type of head pressure control?

  10. #10
    Join Date
    Dec 2010
    Location
    Savannah Ga.
    Posts
    41
    Is there a heat exchanger mounted in the liquid/suction line? Have seen them leak internally and bleed liquid right into the suction line. Those were fun to diagnose!

  11. #11
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191
    Quote Originally Posted by ryan1088 View Post
    Assuming you have the bulb in the right place and insulated well? We do need some numbers to look at. Also does this have some type of head pressure control?
    Insulated and in proper location, no head pressure control, but condensor is in a basement. the basement does get a little chilly in winter about 60degrees, but has never been a problem in past

  12. #12
    Join Date
    Jul 2012
    Location
    Western KY
    Posts
    1,221
    Did u pump down and change valve or pull charge? I'm with JP on the ice ball at 47 SST. Are you maybe grossly over charged?

  13. #13
    Join Date
    Dec 2010
    Location
    Savannah Ga.
    Posts
    41
    Does the system have a heat exchanger installed?

    The more I think about this, the more convinced I am that you probably have a heat exchanger on that system and it is leaking internally, dumping liquid straight into the suction line! Has anyone else ever seen this? Anyone agree?

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