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  1. #1
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    Oct 2016
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    Part of Evaporator coil is frozen.

    Hey Guys,

    I got a general question for you guys.

    As we pretty much know; when an evap coil freezes over, its due to low refrigerant or serious humidity in the box. In my case about 95% of the time, its due to low refrigerant and occasionally its a TXV and rarely, someone left the door open for too long.

    I have been seeing now where some of my Delfield reach ins, roll ins and reach through's are starting to develop frost and in some cases, ice on the very bottom of the coil. I then check back a couple of days later and its gone, then I check again the next week and there is ice again.

    Just wondering what you guys consider that to be? I will start working on something if the ice stays there and gets more and more and it almost always end up being low on refrigerant.

    Just wondering what you guys do when it comes to seeing a small amount of ice on coil, do you guys jump on it and fix it or you let it rest and see if the ice stays there?

  2. #2
    Join Date
    May 2004
    Location
    Plattsburgh NY
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    Quote Originally Posted by Olivero View Post
    Hey Guys,

    I got a general question for you guys.

    As we pretty much know; when an evap coil freezes over, its due to low refrigerant or serious humidity in the box. In my case about 95% of the time, its due to low refrigerant and occasionally its a TXV and rarely, someone left the door open for too long.

    I have been seeing now where some of my Delfield reach ins, roll ins and reach through's are starting to develop frost and in some cases, ice on the very bottom of the coil. I then check back a couple of days later and its gone, then I check again the next week and there is ice again.

    Just wondering what you guys consider that to be? I will start working on something if the ice stays there and gets more and more and it almost always end up being low on refrigerant.

    Just wondering what you guys do when it comes to seeing a small amount of ice on coil, do you guys jump on it and fix it or you let it rest and see if the ice stays there?
    A lot of variables there.
    What do you mean you can't compress liquid!

  3. #3
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    Oct 2016
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    Thread Starter
    Quote Originally Posted by flangehead View Post
    A lot of variables there.
    Yeah, no kidding.

    It's a "general" question meaning its not very specific. You see an evaporator coil that is an 1/8" or 1/6" covered by ice on the bottom, you can hear and feel the evap fan is running, what's your first thought?

  4. #4
    Join Date
    Jan 2016
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    I haven’t seen the ice/no ice scenario your describing. Not saying it doesn’t happen, I just think since you are in-house you would have the opportunity to see something like that while I’m a field tech and wouldn’t.

    I would add lack of air flow as a major reason for evaps to freeze up too.

    For me, I would defrost the coil. I don’t have the luxury of going back and checking on it later so I need to take care of it when I see it. And I’d spend some time figuring out why the ice is building up.

    Maybe your units need more defrosts or a wider temp diff?

  5. #5
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    Oct 2016
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    Thread Starter
    Quote Originally Posted by VanMan812 View Post
    I haven’t seen the ice/no ice scenario your describing. Not saying it doesn’t happen, I just think since you are in-house you would have the opportunity to see something like that while I’m a field tech and wouldn’t.

    I would add lack of air flow as a major reason for evaps to freeze up too.

    For me, I would defrost the coil. I don’t have the luxury of going back and checking on it later so I need to take care of it when I see it. And I’d spend some time figuring out why the ice is building up.

    Maybe your units need more defrosts or a wider temp diff?
    Right, I can go and check it fairly frequent, which I try to do.

    Really, lack of airflow? What causes that? dirty evap coil?

    That does make sense, I normally hook my gauges up (most of the units have service valves) and check after I defrost it just to make sure but 95% of the time, its got a leak.

    The Fridges don't have defrosts, only the freezers do and those are normally fine.

  6. #6
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    It’s very rare for the coils in a reach-in to get dirty enough to cause them to ice up. But I guess it could happen.

    I see them ice up when a fan fails or they block the air flow with boxes or a loose piece of plastic wrap gets sucked into the coil.

    I’m not familiar with the models you have but quite a few reach-in coolers have defrost clocks. In general it would be something to look at if yours had them.


    Sent from my iPhone using Tapatalk

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  8. #7
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    Oct 2016
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    Thread Starter
    Got ya, didn't think of the plastic or cardboard, I have seen plastic on the evap coils on my walk ins, I remove it but I didn't consider it could freeze it up. Good point.

  9. #8
    Join Date
    Jun 2014
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    Low air flow can be dirty coil, or fan motor that drags.

    The low flow causes the air to "linger" longer than designed, in the coil. Air gets colder, moisture can freeze on coil surface.

    Maybe the motor isn't maintaining its speed all the time.

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  11. #9
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    Dec 2014
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    Dirty fan blades too. Thin layer or ridge of dirt, you can lose 20% of your cfm.

    Sent from my SM-G930V using Tapatalk

  12. #10
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    Aug 2002
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    Blades on backwards, wrong rotation motors.

    Ice on the bottom? drop the drain pan and clean it and the drain line!

    Air sensing, CCI, or LP controlling temperature!

  13. #11
    Join Date
    Mar 2007
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    How far does the coil sit in the drain pan? Air flow issue plus running too cold will freeze down there like that.
    For a quick check
    If you stop the evap fan and the whole coil frosts up probably not a charge issue.

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  15. #12
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    Thread Starter
    Okay, it doesen't sit on the drain pan, there is about 1/2"-1" gap between the drain pan and the bottom of the coil.

    On some of them I only see it once or twice occasionally when I am going through all of them and checking them, when they are more persistent and stay there, so far its always been a low charge due to a leak.

  16. #13
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    Sep 2016
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    I've had a temperature control cause this. Being out of calibration or a lower than proper setpoint can cause this to happen especially if the differential is not allowing enough time between cycles. Another thing I would look into is a slight restriction in the metering device or filter. I had a silver king unit with a partially blocked cap tube and while empty the unit cooled and the coil was clear but full of product the evaporator coil would ice up a bit at the bottem. A new cap tube solved that. Another obvious would be check door gaskets.

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