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Ice build up

crash2009
crash2009 Member Posts: 1,484
in A-C, Heat Pumps & Refrigeration
I have been hanging around the Strictly Steam section for about a year now.  The guys over there have helped me get my one-pipe working great again.  Anyway now I'd like to figure out whats wrong with our refrigeration units at work.  So, once again I don't know the terminology, so please bear with me.  Here are a couple photo's that don't look right to me, and I was wondering if you could tell me whats wrong, if its aparent.  Or advise me how to get more information if you need it to tell me whats wrong.  The first photo is outside and its the tubing that comes from the freezer compressor.  The second photo is the same tubing going through the walk-in cooler, on its way to the walk-in freezer.  It doesn't ice up this bad in the summer but its real bad in the winter.

Is this normal for this to ice up like this? 

Comments

  • crash2009
    crash2009 Member Posts: 1,484
    larger line

    The ice build up is on the larger line, the one with the insulation, seems like the insulation isn't working.
  • dave_11
    dave_11 Member Posts: 3
    It's called superheat

    The aged/missing insulation is the culprit but not necessarily the villain... More than likely all is okay with the exception of increased superheat in the refrigerant system during the summer months which decreases efficiency... An iced up suction tube can indicate floodback of liquid refrigerant of which we all know one cannot compress liquid; or to clarify, a compressor cannot compress liquid... But with a freezer, a suction tube can simply be extremely cold with zero return of liquid refrigerant and moisture in the air surrounding the piping freezes to the exposed tube and over time builds up ice like your pics show... If this system has run this way for years then I'm guessing an insulation remodel is in order and leave it at that... To be positive you could have a refer dude check the superheat on the system to insure there's no floodback of liquid refrigerant which will eventually cause compressor failure... Or to educate yourself, locate the instructions that come with a thermostatic expansion valve (like Emerson) and you'll get an idea of how to measure superheat...  cheers,  kooler
  • Wayne_16
    Wayne_16 Member Posts: 130
    Is this a freezer?

    Ice build up on a suction line is normal for a freezer application.  We are not in the AC mode here.  Remember the gas temperature inside the suction line is below the freezing point of water and moisture from the air will collect on the exposed piping and freeze.  Keep your refrigerant guy away from adding/removing charge or changing the txv superheat until other possible causes are eliminated.



    How are the evaporator coils?  Are they also iced over?  May be a defrost problem.  Drain pan problem.



    Things to help answer your questions. 

    Type of unit, walk in, reach in,

    Freezer/ refrigerator

    temperature inside the box

    Temperature the box should be at?

    refrigerant type if known

    Are all the evaporator fan running? 

    Are they running the right direction?



    Once external items are eliminated, then items like refrigerant charge, superheat, txv valve operation can be addressed.  Not before.



    Thanks, Minnesota Wayne
  • crash2009
    crash2009 Member Posts: 1,484
    edited December 2010
    You sure do ask a lot of questions!

    Thanks for your reply.  I have answered some of your questions below using uppercase.  I don't know what an evaporator coil is, or where to find it.  The questions that I have not answered tonight will be answered when I go to work tomorrow.  The 2 pics below are of the site.  It is an L shaped walk-in cooler with a walk-in freezer at the far end.  This is a convience store in a gas station.  The electricity bills are enormous. 





    How are the evaporator coils?  is an evaporator coil the box in the freezer,,,with the fans on it?  IS, THERE IS NO ICE BUILDUP IN THERE



    Are they also iced over?  May be a defrost problem.  Drain pan problem.



    Things to help answer your questions. 



    Type of unit, walk in, reach in, WALK-IN



    Freezer/ refrigerator FREEZER



    temperature inside the box,,,USUALLY -14.5 F, right now its zero F, fans not running (defrost mode I think) 



    Temperature the box should be at? I dont know what it should be



    refrigerant type if known.......On the sticker outside it says TYPE 404 ? and there is a letter after that that I can't read.



    Are all the evaporator fan running? YES



    Are they running the right direction?DON'T KNOW
  • Wayne_16
    Wayne_16 Member Posts: 130
    Walk in cooler with attached freezer

    This helps a lot.  Box temperature for the walk in freezer will be 38 to 41 degrees.  Code prevents temperatures warmer than 41, and economics tend to limit a colder box.  Produce will be damaged if the air temperature is 34 degrees or colder for a long time.  The freezer at -15 degrees is okay depending upon product.  Ice cream needs a temp in this range to stay solid.  At 0 degrees the ice cream is soft in the cartoon.



    The evaporator coil is located inside the cabinet, housing the evaporator fans.  Check for frost ice build up on both sides of the coil,.  The frost on the coils should be even from both sides, top to bottom and left to right.  There should not be any ice coating the coil. 



    The freezer fans should run all the time, unless in defrost mode.  This should be 10 to 30 minutes max, depending upon how the system is designed.  If the fans are off, this may be the problem.  Now the question is to determine if the defrost timer clock is stalled/broken, the fans are bad, a bad fuse/breaker for the fan circuit.  If the fans have been off for a time, the suction line will collect frost ice as the evaporator coil is not adding heat to the refrigerant.  Box temperature will rise etc.



    Check all the door seals and look for other air infiltration leaks,  Air entering the cooler or freezer will rob you of money.  Check for missing threshold seals on the entry doors, broken or torn door gaskets on each reach in door need to be replaced.  Even a small cut in the magnetic door seal will affect efficiency.  Really look at the bottom of the door and the hinge side as the gasket will roll on the frame, eventually tearing.



    The freezer section will have a different refrigerant then the walk in cooler.  R404A is most likely the freezer system.  Is the freezer system the lines with the heavy frost/ice buildup?

    One more thing to check would be the sight glass.  If the system has one, it would be located in the liquid line (smaller line) close the the condensing unit outside.  The sight glass allows a person to see the refrigerant flow inside the tubing.  Generally a properly charged system with a TXV valve (located at the inlet to the evaporator coil) will not show any movement of the refrigerant.  As the system has the correct amount of refrigerant.  If there is flash gas or gas bubbles flowing, this may indicate the system is low on charge and part of the problem.  This is the time to call a qualified refrigeration technician.



    Thanks, Minnesota Wayne
  • Techman
    Techman Member Posts: 2,144
    The frosted

    lines in this unit happen in the colder O.A temps .Why not during the summer? I'm thinking a refrigerant/head pressure related problem. We need box temp, O.A. temp. and hi/low pressure readings.
  • rey
    rey Member Posts: 1
    edited December 2012
    chiiller

    why they full of ice in the suction line to evaporator
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