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  1. #14
    Join Date
    Oct 2005
    Location
    B.C. Canada
    Posts
    904
    Quote Originally Posted by crackertech View Post
    Humm.....................I just don't know were to start with this one.
    Things just went sidewayz

  2. #15
    Join Date
    Feb 2013
    Location
    Cary NC
    Posts
    685
    I do residential, so I was just at a gas station I frequent. He asked me to look at his cooler. Complaint was freezing evap. He turned off the unit the night prior. Pan full of water, so I vacuumed out. Coil was icing up immediately. WR defrost with sencing bulb set at +30 whatever that means. Drain mustbe stopped up, but I suspect the defrost Iis not Iinitiating or not running long enough. But what do I know. R-502 frezone. I passed it to a buddy that can do low and med refrigeration. Know when to say nope.

  3. #16
    Join Date
    Feb 2014
    Location
    cagayan de oro city, philippines
    Posts
    18
    Quote Originally Posted by HVAC LLC View Post
    What are some causes for a partially frozen evaporator (besides low charge) on a walk-in evap, 3 fan Larkin food cooler, full charge 404, was running fine, thermostat set on 38, 5 degree differential.
    Got a call on this, haven't been there yet. Customer defrosted, but may call me back.
    I know that's not much information, but it's pretty much all I have.
    I have done all commercial HVAC, not allot of refrigeration, maybe 20%.
    Thanks.
    deffective txv

  4. #17
    Join Date
    May 2004
    Location
    Plattsburgh NY
    Posts
    224
    Quote Originally Posted by icemeister View Post
    Uneven icing of the evaporator coil like that can be due to an improper distributor nozzle. An oversized nozzle can lead to uneven distribution...essentially overfeed some circuits and underfeeding others.

    More than likely though, your ice buildup is a result of incomplete defrosting.

    I'm assuming this sytem has no defrost timeclock and relies strictly on the off-cycle time to clear away frost buildup. If ALL of the frost is not cleared off, it will re-freeze and become hard ice.

    Add a defrost timeclock and set it up for three 30-40 minute defrosts per day.
    30, 40 min defrosts per day, now that's funny!


    Sent from my iPhone using Tapatalk

  5. #18
    Join Date
    Jul 2012
    Posts
    1,322
    Maybe a starved evaporator.

  6. #19
    Join Date
    Jun 2012
    Location
    Tenn
    Posts
    139
    Quote Originally Posted by HVAC LLC View Post
    What are some causes for a partially frozen evaporator (besides low charge) on a walk-in evap, 3 fan Larkin food cooler, full charge 404, was running fine, thermostat set on 38, 5 degree differential.
    Got a call on this, haven't been there yet. Customer defrosted, but may call me back.
    I know that's not much information, but it's pretty much all I have.
    I have done all commercial HVAC, not allot of refrigeration, maybe 20%.
    Thanks.
    Does the Larkin walk in have a Beacon (1) electronic controller?

  7. #20
    Join Date
    Jun 2013
    Location
    Yakima, WA
    Posts
    104
    A coil that is filled with that greasy lint has decreased airflow, and the defrost doesn't complete itself. After the ice is gone, I usually find a layer of crud.

  8. #21
    Join Date
    Jun 2008
    Posts
    73
    Time clock? If there isn't one, put one in. If the box is relying on off time from the stat then you can also get ice buildup over time due to inadequate defrost. Start with that first before as well as ensuring a full charge and the fact that the system does cycle off.

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