Bathroom fan + wall motion sensor + 110V relay

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  #1  
Old 07-22-11, 12:12 AM
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Bathroom fan + wall motion sensor + 110V relay

OK - So some time ago I was wondering around the big box store and came across a wall mounted (switch replacement) motion detector. I read the package of what kind of voltage it could handle, and thought it would be great in our guest bathroom. Then, I wouldn't have to remind guests to use the fan when they take a shower, etc.

My first attempt was just to hook it up as you would to a light. But this didn't work, for whatever reason. I read it has something to do with the fans initial draw, and that the motion sensor cannot handle turning on the fan.

So I did some digging, and asking questions in stores, and it was recommended that I use a relay. This way, the motion detector would only be turning on the relay, and the power through the relay would be then sent to the fan. GREAT!! Found a 110/120V relay for a good price, and away I go. I test the relay to make sure I understood how to wire it, and it seemed to work fine, and did what I expected it to do.

I then took out my switch and proceeded with the install and hook up of all this. Here is what the circuit would have originally been:

White wire directly to fan.
Black wire running through wall switch then out to fan.

NOW WITH NEW LEVITON MOTION DETECTOR and 110/120V RELAY:

White wire still goes directly to fan
ONE NEW white wire to one post of relay to "charge" the relay when the motion detector is ON.

Black wire from house, to BLACK wire of motion detector (per the instructions) RED wire out of motion detector (usually heading for LOAD) has been put onto the other post of the relay to complete the "charge" circuit, turning the relay "on".

on the other end of the relay, I added ONE NEW black wire to the original house feed (with wire nut) going to one side of the relay, and the original black wire heading out to the fan on the other post opposite the new added wire.

Thought I should mention:
There are two other posts towards the middle of the relay that are not used for this purpose. This relay could act as a switching mechanism between two circuits if desired; one that would be connected when the relay is OFF, and another when the relay is ON.

LETS TEST IT OUT:

When the motion sensor is in the OFF position, fan is OFF.
When the motion sensor is in the ON position, I can hear the relay click, and the fan comes on as desired / expected.
When the motion sensor is in the AUTO position, I hear the relay kick on, the fan comes on, but never turns off. I see that the motion sensor is sensing my motion with a front visible green LED, but even after 30 minutes and more, it never senses anything and the fan remains ON!

I have set all the sensing adjustments in various positions to see if it ever turns off, but it never changes, the fan has been running for hours with nothing moving in the bathroom.

Have I done something wrong?!?!? It does seem like it is wired properly, as it does what I expect it to do when it is OFF and ON, but that really isn't the point of all this, now is it?!?!? I want the damn fan to turn on when someone enters that room. I have tried reversing the black and red wires that come out of the motion detector, just to try, and although it still worked the results were exactly the same too.

So I am reaching out. Any ideas? here are more technical specs of what I am using:

LEVITON PR150 Wall Switch PIR Occupancy Sensor
PR150-1LI > Wall Switch > Occupancy Sensors > Lighting Controls (Box Mounted) > All Products from Leviton Electrical and Electronic Products
ESSEX 90-382 DPST HEAVY DUTY FAN RELAY 120 VOLT 77657
Surplus City Liquidators
 

Last edited by speeddemonrs; 07-22-11 at 12:14 AM. Reason: mis-type
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  #2  
Old 07-22-11, 12:25 AM
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The answer is in the description for the motion sensor which I will paste below.

Description
40W/VA Min


That motion sensor requires a MINIMUM LOAD of 40 VA (volt-amperes) or 40 watts. The relay is likely less than four watts or less than one-tenth the minimum load. Try connecting a regular incandescent light bulb of at least 40 watt rating in parallel with the relay coil and see if that works.
 
  #3  
Old 07-22-11, 05:23 AM
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Most of these type of switches use a triac to switch the load.
The instructions will say that they should only be connected to incandescent or magnetic ballasts on fluorescent lights and not to transformers.

Your motion sensor may have difficulty in firing a relay.
 
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Old 07-22-11, 10:10 AM
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Why not have the motion detector turn on the lights in the bathroom as well as the fan? That way you would get the appropriate load required for the motion detector to operate correctly.
 
  #5  
Old 07-22-11, 01:39 PM
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Well, it does work properly when I hook up the light as well as the fan to it. I just didn't really want to leave the light on when no one was in there, but wanted to keep the fan running awhile. Well, its not the perfect set-up that I wanted, but at least it works. I wonder about using some sort of a capacitor added to simulate a 40W+ draw.... ?
 
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Old 07-22-11, 01:42 PM
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Originally Posted by speeddemonrs View Post
I wonder about using some sort of a capacitor added to simulate a 40W+ draw.... ?
Something along those lines would probably work but as long as you're going to be using 40W of power why not have to do some good with the lights. Could you possibly just have to turn on one small light and let the other switch still control the rest of them?
 
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Old 07-22-11, 01:46 PM
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Currently there is only one can light in this bathroom anyway. Perhaps I should add another can light adjacent to the fan which is above the toilet. this way the standard can light that is in place over the shower can be just for the shower, and the new can can address lighting over the toilet, while supplying enough amperage to the detector to run the fan.
Hmmmmmm - that might just work. As a bonus, my wife wanted a second light in there anyway!!!

Although, if I were to do that, I would have to add a whole new lead wire from the switch box to the new light.
 

Last edited by speeddemonrs; 07-22-11 at 01:49 PM. Reason: adding information
  #8  
Old 07-22-11, 01:48 PM
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Glad I could help, making the wife happy is a additional plus!
 
  #9  
Old 07-22-11, 05:02 PM
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Hi Greg - thanks for the input. I know the issue with the motion switch would not drive the fan when it was hooked up directly, and it does seem to work and is able to drive the relay fine, but as others had pointed out, the draw of the relay may not be enough to trigger the relays internal timer to shut off. I had also tried to use another motion detector on a CFL bulb in my wife's closet, and although it worked (sensed motion, turned on, and turned off after a set time) it allowed some "energy bleed through" and since CFL bulbs are so efficient, the bulb sat there and flickered dimly when it wasn't on. So I had to choose between two evils. Either switch back to a regular switch and let my wife leave on the CFL when she wasn't in the closet (why she doesn't turn it off I don't know) OR replace the bulb with a regular incandescent bulb. I decided to have the CFL there in her closet.

Thanks for the input!!

Robb
 
  #10  
Old 07-22-11, 08:18 PM
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The light abovr the shower will need gfi protection.
 
  #11  
Old 07-23-11, 12:58 PM
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justin what code reference states that a shower light has to be gfci protected
 
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Old 07-23-11, 02:37 PM
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Originally Posted by bobbi 5 View Post
justin what code reference states that a shower light has to be gfci protected
Source: NEC 2008

551.53 Luminaires.
(B) Shower Luminaires. If a luminaire is provided over a
bathtub or in a shower stall, it shall be of the enclosed and
gasketed type and listed for the type of installation, and it
shall be ground-fault circuit-interrupter protected.
................................................................................
 
  #13  
Old 07-23-11, 03:24 PM
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ray that code is for recreational vehicles and recreational vehicle parks not residential housing.
 
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Old 07-23-11, 04:38 PM
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Opps that's what I get for doing a quick search and ignoring context. Thanks for the correction.
 
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Old 07-23-11, 05:08 PM
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does anyone know the code reference that states the shower light has to be gfci protected? anybody.
 
  #16  
Old 07-25-11, 09:58 AM
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Shower lights do not require GFCI protection unless the fixture manufacturer requires it in the installation instructions. You are required to use a light fixture or recessed trim specifically marked for use in a shower. With a recessed light you use a standard can for rough-in and a shower trim to finish it out, usually has a non-shatter dimpled lens and a gasket to seal to the tile/sheetrock to keep out the water.
 
  #17  
Old 07-25-11, 10:15 AM
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Originally Posted by speeddemonrs View Post
I just didn't really want to leave the light on when no one was in there, but wanted to keep the fan running awhile.
These have worked well for me: EnergyFederation.org | EFI Fan/Light Time Delay Switch
 
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