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Thread: Walk-in freezer; Confused about the install...

  1. #1
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    Walk-in freezer; Confused about the install...

    I really want to get this figured out.
    It's a new walk-in freezer that is located outside about 3 feet from the structure. When I look at the various parts I try to visualize how it how all the pieces of the puzzle go together, but then I get confused...

    I'm not focusing on the condenser, that's pretty straightforward.
    It's the inside unit cooler that confuses me.

    Basically this unit has the evaporator, I'll have a disco, probably located inside the unit on the back wall?
    The defrost timer I'm assuming will be located inside the building adjacent to the freezer, so there will be the conductors for that.
    There is a LLS and a t-stat mounted on the back side of the unit.
    Then there's a twin lead conductor stubbing out the side of the unit which I'm told is the heating element. I'm not sure what to do with that...

    I try and draw out a one line diagram to figure out my connections but get confused.
    Obviously power Will come to the disconnect. Then power to the actual evaporator unit.
    I'll need interconnecting conductors between the time clock and the evap unit.

    I'm not quite sure how the LLS, the t-stat, and the leads for the defrost heater fit into the puzzle though...

    Also, for the defrost timer I have 4 conductors (n, x, 4, 3). Does that get power from those conductors?( I.e.- only need 4 conductor, not additional for power)

    Thanks for comments and input..

  2. #2
    Join Date
    Dec 2007
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    Quote Originally Posted by sw_ross View Post
    I really want to get this figured out.
    It's a new walk-in freezer that is located outside about 3 feet from the structure. When I look at the various parts I try to visualize how it how all the pieces of the puzzle go together, but then I get confused...

    I'm not focusing on the condenser, that's pretty straightforward.
    It's the inside unit cooler that confuses me.

    Basically this unit has the evaporator, I'll have a disco, probably located inside the unit on the back wall?
    The defrost timer I'm assuming will be located inside the building adjacent to the freezer, so there will be the conductors for that.
    There is a LLS and a t-stat mounted on the back side of the unit.
    Then there's a twin lead conductor stubbing out the side of the unit which I'm told is the heating element. I'm not sure what to do with that...

    I try and draw out a one line diagram to figure out my connections but get confused.
    Obviously power Will come to the disconnect. Then power to the actual evaporator unit.
    I'll need interconnecting conductors between the time clock and the evap unit.

    I'm not quite sure how the LLS, the t-stat, and the leads for the defrost heater fit into the puzzle though...

    Also, for the defrost timer I have 4 conductors (n, x, 4, 3). Does that get power from those conductors?( I.e.- only need 4 conductor, not additional for power)

    Thanks for comments and input..
    N is the neutral to the timer motor (if it is 120 volt, with 240 volt timer just consider it to be L2 to the timer motor)

    X goes to a solenoid that releases the contacts before timed cycle is up, it gets powered by the "defrost termination thermostat". Basically if the evaporator reaches set point of this thermostat - there is no more ice on it and no point in adding more heat to inside of the freezer - so it terminates the defrost cycle before it's preset time is up. This is an optional thing and isn't always used.

    3 - should be normally closed contact (should be a terminal 1 to go with it), it opens when a defrost cycle starts. Should open circuit to whatever controls the compressor - typically a solenoid valve that closes refrigerant line and compressor then shuts down on pressure switch after "pump down". Often is desirable to make it shut down the evaporator fan as well - that way it doesn't disperse defrost heater heat anymore then necessary into the freezer and keeps that heat at the coil being defrosted as much as possible.

    4 -should be normally open contact (should be a terminal 2 to go with it - and is normally jumper-ed to terminal 1 and has "L1" of defrost timer motor connected to this point also. This terminal should feed the defrost heater.

    Is common to have a heat tape in the condensate drain so it doesn't freeze shut and can't drain. Those often are on 24/7 though you normally only get condensate during a defrost cycle. The rest of the time it condenses and freezes right on the coil, and therefore the need for defrost cycles.
    I live for today, I'm just a day behind.

  3. #3
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    Thanks for the info!

    There is heat tape on the condensate lines. Am I to assume it needs 240v? The time clock they left is 240.

  4. #4
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    Also, can the defrost time clock be mounted inside the freezer? That would simplify things, but not sure if it's rated for that environment.

  5. #5
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    Also, is it necessary to use sealtite to connect up these parts? Or can you just use regular flex...

    And can the disconnect switch that will be mounted back side of evaporator just be mounted in a handy box or should it be mounted in a WP box?

    I feel like there's a fair amount of stuff that's already exposed to moisture (evaporator terminal board, etc.).

  6. #6
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    Quote Originally Posted by sw_ross View Post
    Also, is it necessary to use sealtite to connect up these parts? Or can you just use regular flex...

    And can the disconnect switch that will be mounted back side of evaporator just be mounted in a handy box or should it be mounted in a WP box?

    I feel like there's a fair amount of stuff that's already exposed to moisture (evaporator terminal board, etc.).
    Outside of wash down, which doesn't typically happen all that often in a freezer, humidity inside when running is low,y your evaporator coil is a dehumidifier. Opening the door and allowing outside air in brings moisture with it though and will condense on cold objects. keeping a constant fan helps make that air condense in the evaporator even if compressor isn't running. I have always used standard boxes and FMC or EMT with set screw fittings.
    I live for today, I'm just a day behind.

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