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  1. #1
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    Newbie refrigeration question

    Howdy this is my first post here. I have been reading and learning here for a couple of years.
    I am a residential and light commercial hvac service tech with a small company in Oklahoma.
    I have been in the hvac field for about 3 years now but i have been interested in the refrigeration cycle (and anything else mechanical) since i was a little kid reading my copy of the world book encyclopedia.

  2. #2
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    Now for the question.
    I will do my best to explain because i cant post pictures untill i make 5 more posts.
    I was in a local gas station buying gas and noticed a built in beer type cooler (sorry i dont know the correct terms) being used for bagged ice and frozen foods. It has an evaporator unit in the middle hanging from the top of the case with a copper drain line running to the back wall and along the wall at least 6 feet. So obviously the drain line being in the case at sub freezing temps would freeze up. So there was pipe heat cable wired in and wrapped around the drain but not insulated. So i was wondering is this normal installation practice or is there some other way it should be done? It struck me as a waste of energy heating a pipe inside of a freezer without insulation. Alse the bottom of the evaporator box was caked with ice.
    Last edited by R600a; 07-31-2019 at 06:32 PM. Reason: Spelling

  3. #3
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    The bottom of a freezer being caked with ice is typically because the drain line is frozen or otherwise clogged and the water from each defrost cycle is not draining. So the drain pan overflows, the water freezes on the floor - and you saw the result.

    Was the drain line's heat tape warm to the touch?

    Yes; the heated drain line should be insulated.

    What I do is to run the heat tape inside the drain line.

    PHM
    -----------



    Quote Originally Posted by R600a View Post
    Now for the question.
    I will do my best to explain because i cant post pictures untill i make 5 more posts.
    I was in a local gas station buying gas and noticed a built in beer type cooler (sorry i dont know the correct terms) being used for bagged ice and frozen foods. It has an evaporator unit in the middle hanging from the top of the case with a copper drain line running to the back wall and along the wall at least 6 feet. So obviously the drain line being in the case at sub freezing temps would freeze up. So there was pipe heat cable wired in and wrapped around the drain but not insulated. So i was wondering is this normal installation practice or is there some other way it should be done? It struck me as a waste of energy heating a pipe inside of a freezer without insulation. Alse the bottom of the evaporator box was caked with ice.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  4. #4
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    There should be insulation over the pipe with the heat tape.
    There are drain pan heaters in the pan of the evap, if it’s caked with ice, the pan heaters are probably no good/not working.
    Also, if there is a door not sealing or the fan klixon not working/ jumped out, there will be excessive frost around the evap due to humidity levels.
    It’s a reach in freezer. Or a walkin freezer with doors.
    I run the heat tape on the bottom of the pipe, zip tied every 16-20”, wrap around the hub of the evap, and wrapped around the trap. If it’s 7/8-3/4 drain line I put on 1-1/8x3/4 armaflex and miter my 90’s and tees.

  5. #5
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    Thanks for the replys.
    That makes sense i was just walking by and it caught my eye.

  6. #6
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    My first thought was what a waste of energy. Then i started wondering about the ice on the bottom of the evaporator box. But i am not a refrigeration mechanic my self so i wanted to ask some experts.

  7. #7
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    Frost tex self regulating heat tape uses max 60Watts on a 12' run. Properly insulated probably 12 watts. Not enough to worry about!

  8. #8
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    Well it looks like the drain is probably defrosted but i am not so shure about the drain pan.

  9. #9
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    Just in case anyone was curious i will try and post pics.

  10. #10
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    I would any way but i don't see how.

  11. #11
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    All larger freezer boxes have drain lines on the evap. A heat tape installed correctly which i wrapping the cable around the pipe and using 3/4" insulation is the proper way to install a drain line. Otherwise the drain will freeze up and cause an ice freeze up and may take out the evap fans and in worst cases, the compressor and food loss

    Tim Parsons

  12. #12
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    I like the 3/4" insulation but I like to run the heat tape Inside the drain line. That's where the heat is really required anyway.

    PHM
    --------

    Quote Originally Posted by TPARSONS64 View Post
    All larger freezer boxes have drain lines on the evap. A heat tape installed correctly which i wrapping the cable around the pipe and using 3/4" insulation is the proper way to install a drain line. Otherwise the drain will freeze up and cause an ice freeze up and may take out the evap fans and in worst cases, the compressor and food loss

    Tim Parsons
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

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