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Thread: mystery ice

  1. #1
    Join Date
    Dec 2004
    Posts
    56
    My patients name: Hill glass 4 door reach in icecream case

    ailment: aprox. every 6 weeks someone has to deice the fans

    treatment:

    1st visit: noticed ice build up is only behind the fan shroud not in the drain or on the evap. my first thought was case is not completly drained when fans come on and water gets pulled back into fans and freezes progressivly building up in layers. i programmed in an exageerated drip time, went from 5min to 15 min.

    2nd visit: just a follow up visit to see if ice was back and it was. first off i deiced case by dumping 30 gal trash cans full of water into bottom of case hose wasnt an option. the final pail of water i dumped floor wax in the water first then washed case out with it, thinking perhaps wax would help water bead and flow to drain (act of desperation). i changed a check valve that seemed to be leaking slightly, restarted and checked superheat 30 degrees, hmm uneven frost pattern maybe im onto something. superheat would not dial in for me so i pump it down pull the screen nice n clean so i change orifices in the valve went from a #2 to a #3. visaul inspection of the valve leads me to believe the sys has acid in it (parts have that pretty copper clad look to them)i restart and dial in about a six degree superheat but valve has large swing when it hunts not a good steady reading but case had lots of traffic so im gonna let it balance and recheck.

    has anyone out there ran into this or have any thoughts on other things to look at for the source of this?

    thanks for your thoughts guys

  2. #2
    Join Date
    Nov 2001
    Location
    lorain county,Ohio
    Posts
    215

    IS THIS A HOT GAS DEFROST CASE

    If it is,is the suction line down to the bottom of case. might need the heat on the pan to warm metal for better draining during the defrost, also are the fans shutting down soon enough or I don't recall if they ever used them or not, but are they reversing fans ?


  3. #3
    I assume you had NO PRESSURE / temp drop across your filterdrier!?!?!?!?!?!

    When you noticed the copper plating inside the TX, why oh why did ya replace the #2 with the #3???

    I mean, maybe the guts were tweaked inside the valve and needed replacement. Maybe the power head was defective.

    I do not grasp why you changed to larger hole.

    Afterall .. that #2 hole USED to feed enough freon. And since it used to work ... it outa work now.

    Unless the guts or head or drier is not working correctly.

    Inquiring minds ... we wanna know

  4. #4
    Join Date
    Dec 2004
    Posts
    56
    When you noticed the copper plating inside the TX, why oh why did ya replace the #2 with the #3???

    first off i inspected the valves parts and everything appeared to be working corectly mechanically. i did change the powerhead as well for good measure,but there was no problem with it. as far as the comment of working all along, i dont know that it has been, im new to the store and it was taken over from a piss poor contractor. in fairness i should of taken the time to find out the btu load of the case and calculated the orifice size but instinctivly it seemed undersized to me. now it does seem to have a bit of a temp swing in its hunt which may have to do with the increased orifice so i may of compensated and treated a sympton rather then corrected the problem.


    secondly if your asking me about the drier in the case there is none if your asking me about the drier at the rack the answer is no it was not checked but i highly doubt that is where the problem is but regaurdless i will be returning to put in some hh driers to clean up the system so they will be changed in the near future regaurdless of thier current condition.

    yes this case uses hotgas for defrost steven

  5. #5
    Join Date
    Sep 2001
    Location
    East Stroudsburg, PA
    Posts
    13,215
    Is this a real old Hill case with the fans up front, so you can see part of them with product in the case, through the return grill?

    That case should need 3/4 ton of TXV MAX. A one ton ould probably be uncontrollable.

    I am NOT familiar with the orifice sizes you guys are talking about- I just don't use the Sporlan valve kit, because, and to some of you I'll sound like a broken record, the TXV's ALMOST NEVER go bad. The power elements fail, but there is ALMOST NEVER an actual valve failure.

    I carry a selection of 43, 53 and 83 power elements, and have never been caught with my pants down. IMO, those kits are GREAT for installers. They often find themselves needing valves, due to misordering/nonordering.

    Now, if that is one of the older cases that I described, (and a model # would be nice...) the bottom pan of that case must hit 40 degrees before the case terminates it's defrost. It should have one defrost per day. If your superheat is still high with a larger orifice in it, I'd seriously consider installing a sightglass at the TXV temporarily to see if there is flashing at the case.

    If you don't check the pressure drop of the filters on an unfamiliar rack, you're begging for trouble. I ALWAYS check it on racks that I don't regularly service, or on racks that I am new to. You would be SHOCKED at how many I find that are showing a 20 pound or greater drop, adn how many I find missing the 100 mesh strainer. It's really not funny, and it's a nagging problem, at least around here.

  6. #6
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,260
    The #2 cartridge (QC-2) is good for 1/2 ton on R502/R404A and the #3 (QC-3) will do 1 ton according to the Sporlan Q-Valve quick selection chart. I have the Q-Body kit and find it comes in handy for service particularly when I can't rely on my wholesaler to keep sufficient parts on their shelves.....I keep it on mine.

    If I had a 1/2 ton rated valve in that case that was hunting, I 'd suspect flash gas/ restriction before valve size.....especially with a high load on the case. An under sized valve would be wide open and therefore steady.

    Floor wax??? Interesting concept. Have you tried Pam? I've used that a couple of times on medium temp coils where the water beads up and won't drain off the coil.

    Is this a ZAR Hill case?

  7. #7
    I love hot gas defrost. But then again, I have never thought it was any trouble to have to fix the broken lines when a systems hasnt been built correctly.

    But when it is built right, it's great ... in my book.

    Must be an old sucker.

    The reason I made note about the orofice change is ... a schmuck probably wouldnt know there was an orofice in that valve. Next, they probably wouldnt be able to fit their channel lock pliers up in there to remove the orofice in the first place.
    Hacks tend to change the valve at the first sign of trouble, of any kind relating to feed.



    I had a valve on a w-i freezer late one Saturday night. it was shut down tite! Instead of replacing the head with something on the truck, I went on this quest to open a supply house and find me a new valve. The whole danged valve! A complete whole valve!!!

    Totally unnecessary!!!

    Since I've met Dave, my whole life is easier now that I have taken his course in "how to fix problems you never knew you had."

    Dave, was it called "how to do more with less"?

    Whatever your book was called.. I dont know ....


    It just made sence to me. So that was why I brought up about the orofice change.
    Cause the guy before you probably didnt mess the orofice up, possibly something else was wrong, but not that one part.


    Just my two bits.



  8. #8
    Join Date
    Nov 2004
    Location
    Florida
    Posts
    34
    r-12, Did Daves book teach you how to spell? No just joking. But really your spelling sucks. Where can i get a copy of Daves book?

  9. #9
    Join Date
    Sep 2001
    Location
    East Stroudsburg, PA
    Posts
    13,215
    Originally posted by R12rules
    Since I've met Dave, my whole life is easier now that I have taken his course in "how to fix problems you never knew you had."

    Dave, was it called "how to do more with less"?
    "How to stock your truck on the cheap."

  10. #10
    Join Date
    Dec 2004
    Posts
    56
    the case model number is czer5 i thought it was a 4 door case but it must be a 5 and the suction line is securely strapped to the bottom of the case. i did look at that too just frogot to mention it in original post.

    icemiester:
    just a follow up comment on what you posted about txv`s, this one wasnt hunting, it was feeding. it just wasnt getting superheats. suction sat temp was -20 but sensible temp was +10 with valve fully open, once i changed orifices i throttled valve way back and im getting decent superheat readings (sensible temp -15). as far as the ice goes its got me puzzled on its source but when i get to the bottom of it ill post a follow up thread on it for those of you intrested in hearing the end conculision. and by all means if anyone has any new thoughts please feel free to share them cause im a lil bit stumped on this one.

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