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  1. #1
    Join Date
    Jun 2010
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    Miami
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    Always best to ask

    My fire department inspector says we need a switch inside the walk in freezers to kill the evaporator fans in case someone gets trapped inside.

    These are normal pump down type systems. One evaporator is 120 volt but the other one is 220 volt.

    I assume I'd want to kill the liquid line solenoid too. Not too sure if I need a mushroom head push/pull switch with low voltage wiring leading to a contactor. Maybe a line voltage toggle switch is good enough?

  2. #2
    Join Date
    Jan 2010
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    6,592
    Is there presently a service switch in the boxes for the fans ?

  3. #3
    Join Date
    Jun 2010
    Location
    Miami
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    258
    No. The 120 volt one just plugs into a ceiling mounted receptacle. The 208 volt one is all hardwired.

    Kinda looking to find out if NEMA 4X and/or low voltage is required.

  4. #4
    Join Date
    Jan 2010
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    6,592
    I would ask the local electrical inspector what he wants. I would also think that code would require a disconnect within sight off the evaporator.

  5. #5
    Join Date
    Sep 2008
    Posts
    586
    How about a double gang switch box with a single and double pole switch and a bunch of liquidtite.

    You could do a second set for closing LLSV or perhaps just the valves, it not the fans that are a problem were someone to be trapped, they create heat and a bunch of noise

  6. #6
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
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    1,385
    I have never heard of a fire code like this, you will have to ask the fire chief what he wants to be sure. Like VTP99, though, I have heard that there is an electrical code that requires a disconnect within line of sight of any mechanical equipment. I also believe it is against electric code to have a cord and plug coming out of the cooler evaporator.

    If you are going to shut off the fans, it is strongly recommended to also have the solenoid shut off at the same time. Otherwise, you run the risk of slugging the compressor.

    With a standard 115v walk-in cooler, I usually set them up with a single pole toggle switch to break the hot wire that feeds the fans and thermostat. If by some chance, the fans and the solenoid are on separate circuits, or the wiring is too hard to trace out, you can use a double pole switch wired in series with the thermostat on one pole, and with the hot wire to the fans on the other pole.

    With a 230v Freezer, it gets more complicated. Since power to the fans and defrost heater usually come from the defrost timer, it is usually best to wire the disconnect to break both hots to the defrost control. Hopefully, if you do this, your solenoid will shut off too. Otherwise, if you just break 2 hot wires right near the evaporator to get the fans and solenoid to shut off, the heaters will still become energized when it goes into defrost, and that could be dangerous to an unknowing service guy.

  7. #7
    Join Date
    Apr 2007
    Location
    Saint Augustine, Florida, United States
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    1,164
    show him the door......

  8. #8
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    10,460
    Quote Originally Posted by Russ57 View Post
    My fire department inspector says we need a switch inside the walk in freezers to kill the evaporator fans in case someone gets trapped inside.
    As JWB alluded to, the safety release mechanism on the door latch should be all the fire department needs.

    While I've never had this brought up by a fire inspector, the disconnect requirement that VTP99 mentioned has come up a number of times with electrical inspectors. I don't know the chapter and verse of it all, but I believe there's a section in the NEC which allows for no disconnecting means for such installations. Perhaps Wolfdog knows of it.

    Think about this a moment. Do you know of any supermarket where there are disconnects for each case? I thought not.

  9. #9
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,596
    The 115 volt cord is the drain heater, I'd bet.

    Maybe the fireman should leave a fire ax in there??

  10. #10
    Join Date
    Jun 2009
    Location
    DFW, TX
    Posts
    675
    Just put a single pole switch to break the "4" terminal coming from the timer to the evaporator. That should kill fans and solenoid.

  11. #11
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
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    1,385
    Quote Originally Posted by trippintl0 View Post
    Just put a single pole switch to break the "4" terminal coming from the timer to the evaporator. That should kill fans and solenoid.
    Please don't do the above advice if you have a 230v device. You really need to break both hots, otherwise you could hurt or kill someone.

  12. #12
    Join Date
    Sep 2008
    Location
    Western PA
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  13. #13
    Join Date
    Sep 2008
    Location
    Western PA
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    Quote Originally Posted by icemeister View Post
    Think about this a moment. Do you know of any supermarket where there are disconnects for each case? I thought not.
    Believe it or not, more and more cases are coming from manufacturers with service switches for the fans

    Barker and Hill/Phoenix are leading the charge. Well, when they can get the switches wired properly....

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