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Discussion Starter #1
I have a wine room with a cooling unit where, by design, the fan runs continuously. I would like to shut the fan off automatically when someone comes into the room.

I think a motion switch that turns OFF when motion is detected would be perfect. I am surprised that I can't find one. Seems like they are all designed to turn a device to ON when motion is detected.

Any suggestions?

Thanks

RandyC
 

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Your best solution IMHO is to use whats called Definite Purpose Contactors.

You need to go to your supply house and know the following info (all assuming you are in a residential configuration):

How many Hot legs are you switching
whats the load you are switching (either watts or amps)
whats the voltage and phase configuration you are switching

And ask for a "Normally Closed" contactor and a 120 volt AC coil

They might have to order it in and I would estimate you are looking in the area of 100 bucks to do this. Plus the motion sensor.

You will have to put the contactor inside a junction box (probably 6x6x6/4) and make your connections in that.

then all you do is install your Sensor to the coil control, wire in the contactor and you are good to go.
 
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I would think that a switch such as a proximity switch on the door would be better suited for that purpose. This would keep the fan off while the door is open but would complete a circuit once the door was closed restarting the fan.

Depending on the size of the fan, it may be possible to put the switch in series with the fan, making it a rather simple circuit.

Mark
 

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http://www.nxtbook.com/nxtbooks/ps_legrand/catalog1112/#/38

Try that too.

1201 series from Pass and Seymour. I cant remember if it is a N/O or N/C switch. It will do up to 15 amps.

TA502/503 from Tork/NSi industries is the same thing.

It is an ok solution, but theres a flaw. The door has to stay open for the fan to stay off, but you also run into the possibility of someone LEAVING the door open.

you also could do something like a Magnetic switch system that is rated for 120v/15a normally Closed.

Same problem exists...

I think you need to look into a DP Contactor system to prevent accidental loss of cooling.
 
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What kind of cooling unit is used? Would it even allow the disconnection of the fan without creating further trouble? (e.g. - freezing of coils?)
 

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Discussion Starter #6
Thank you for your help. I did not understand - but forwarded your info to my electrical contractor. It still took a couple of trips and his supplier had to re-order to get the right stuff, but we finally got it to work!

I don't know where I would have ended up without your input. Thanks again!

Randy
 

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Discussion Starter #7
I appreciate your questions. I consulted with the refrigeration tech - who designed the system, with your concerns. He assures me that everything will work fine.

Randy
 
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