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Thread: Heater tape

  1. #1
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    Heater tape



    Hi there,I am installing a new freezer store and the owners preferred location for the evaporators would mean an 8m drain run.Obviously I am trying to persuade him to let me put them nearer an outside wall for a shorter drain run.Have any of you guys had such a long drain in a freezer store and which heater tape did you use ?.Thanks .



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    Re: Heater tape

    Hi Doni
    That's a ridiculously long pipe run and just where is the vapour seal going to be?

    Without a doubt the best option for using a heater Tape is self regulating tape spiral wound around the outside of the drainline and then insulated with Armaflex Insulation ( Or similar product.)
    If this is not designed correctly you could have your Evaps in defrost mode more often than they are in Freeze mode.
    Grizzly
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    Re: Heater tape

    Thanks for the reply Grizzly,excuse my ignorance but what do you mean by the vapour seal?.At the moment we mostly use heater tape fitted inside the drain and never really have a heater tape over 3m.Thanks again for your help.

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    Re: Heater tape

    Ok Doni
    Simply put and preferably as near to the drainline fitting to the evap / cooler tray.
    There needs to be a means of trapping some of the water that is being drained off.
    Effectively sealing the drainline from the ingress of the (Higher Pressure ) warm moist air from outside.
    Traditionally a P trap or S trap as used by plumbers is used by many.
    A Plumber uses a Trap to stop Drain smells percolating back up and out of the plug hole.

    Similarly a Refrigeration Engineer needs to. As I have said stop the air from outside the Refrigerated area being drawn up the drainline and meeting the drier and significantly colder air inside.
    If you don't have a vapour seal all that will happen is.
    Whenever the evap / Cooler is not on defrost the Air from outside will flood into the Refrigerated Zone via the drainline. You can even get ice crystal forming which will eventually form a blockage at the drain outlet.

    crystals at iced up drainline.jpg ice crystals at drain mouth.jpg


    This warm moist air even whilst sitting in the drainline can condense and freeze.
    Simply put a wet seal as near to the drain tray but outside of the freezer envelope is absolutely necessary.

    Basic stuff but many modern designers think they know better.

    Hence the pictures from a 5 year old plant that freezes up all the time and introduces vast amounts of moisture into its store.
    Due to Modern design ethics!
    Still fighting to get mods done after nearly 5 yrs.
    But Hey what do I know?

    if you look at the photos you can see the gray green residue (Dust) that prevails in any cold store of sufficient size.
    This dust which accumulates on the cooler fins will eventually be washed down the drainline.
    Its a mixture of Cardboard, Concrete and pallet wood dust usually.
    It's Humidity and temperature related.

    As it flows down the drainline some is trapped around the heater tape.
    Just like a tampon in a sewer!
    A blockage will occur, the heater tape until it fails will create a polo mint type of effect.
    Until the drainline eventually blocks!
    These blockages electrically stress the heater tapes and cold spots are generated!
    Drastically reducing the effectiveness of the drains to remove the collected moisture from the coolers.

    None of this happens when you spiral wind around the periphery of the drainline. Its just a practical way of achieving what is needed without further obstructing the flow of the water which is draining away.
    Don't forget to insulate the outside of the pipe afterwards.


    Are people not teaching these practises any more?

    Cheers Grizzly
    PS 3mtrs is to long!
    Last edited by Grizzly; 15-10-2017 at 10:19 PM.
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    Re: Heater tape

    Grizzly thanks again for the reply and great advice.We would normally fit a p-trap most of the time but not always if im honest.I spoke with my customer today,more determined about locating near an outer wall after your advice and i am going to insist on this now.Thanks again,Dominic.

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    Re: Heater tape

    Glad to of helped a little!
    Grizzly
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    Re: Heater tape

    Maybe sometime you can help someone on the forum too!
    Its what makes this site special.
    Grizzly
    Despite the High Cost of Living it still remains Popular!

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    Re: Heater tape

    we did alot of new and revamp refrigeration installs for 1 of SA's largest supermarket groups, and there were a few times that we had long drain pipe runs in freezer rooms. Heater tape wrapped on the outside and insulation over that and bobs your uncle. Traps at the drip tray. all piping 1 1/8 copper.
    never had any issues.

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    Re: Heater tape

    Hi Mike,thanks for the reply,would you put a trap inside a freezer?,we would always have it outside.

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    Re: Heater tape

    I would have thought trap outside with provision to clean it in accessible location as well.
    Good fall on pipe also helps.
    Make sure pipe labeled with heat trace under insulation so to warn people.

  11. #11
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    Re: Heater tape

    Sorry trap on outside. traps on inside were on the suction line.

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