3-way switch update *almost* works...


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Old 08-22-16, 11:11 PM
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One 3-way switch must be left in "on" position? [SOLVED]

Hi guys,

My wife and I just bought a house that was full of incandescent lighting. I replaced all the bulbs with LED equivalents, and where necessary, LED-compatible fixtures.

The lights over the stairs were the only existing LED lights, and they were much too bright. They were recessed units with built-in LEDs, so I couldn't replace the bulbs.

So I thought I'd add a dimmer. There was no guarantee it'd work with the older LED fixtures, but it seemed worth a try before having to replace the fixtures.

The lights are controlled by two 3-way switches, at either end of the stairs. I decided to replace the downstairs switch—the one closest to the breaker board, in case that's important—with a Lutron LED-compatible 3-way dimmer-on/off switch, model DVCL-153PR-WH.

I carefully noted the connections to the existing switch:

• One black wire – to switch's 1st brass screw

• Another black wire – to switch's 2nd brass screw

• White wire – to switch's black screw, marked "COMMON"

There was no ground screw, but one of the box's screws was connected to a ground wire, so the switch was grounded through the box.

Lutron's instructions said:

3-way switches have wires connected to three screws plus a ground screw. One of these wires is connected to a screw of a different color (not green) or labeled COMMON. Tag this wire to identify it when removing.
So I assumed the COMMON wire was the white one, above.

Rather than screws, the dimmer had these wires:

• Black
• Red
• Red w/white stripe
• Green

The instructions then said to connect the ground—so I connected the dimmer's green wire to the box's ground screw. The instructions continued:

• Connect the tagged wire to the black wire on the dimmer.
• Connect one of the remaining wires to the red wire on the dimmer.
• Connect the remaining wire to the red/white wire on the dimmer.
So, using the wire nuts provided with the dimmer, I:

• Connected the box's white wire (the one that was connected to the old switch's COMMON screw) to the dimmer's black wire

• Connected the box's two black wires to the dimmer's red and red/white wires, respectively.

When I turned the power back on, the dimmer worked perfectly (yay!). And I found I could turn the lights on and off from either switch.

However, if I turned the lights off at the downstairs switch, flipping the upstairs switch had no effect. Only when the downstairs switch was "on" could the upstairs switch control the lights.

So I turned the breaker back off and reversed the connections to the dimmer's red and red/white wires. Since the instructions said it didn't matter which way they were connected, I figured it couldn't hurt.

This reversed the switches's functionality: Now I could control the lights from the downstairs switch only when the upstairs switch was left "on".

Any idea what I did wrong? Is it possible the wrong wire was connected to the old switch's "COMMON" screw? But then the 3-way switching wouldn't have worked, would it?

Thanks! Sorry to be so long-winded, BTW; I just didn't want to omit anything significant. Cheers, Ander
 

Last edited by ander; 08-22-16 at 11:30 PM.
  #2  
Old 08-22-16, 11:32 PM
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Ah—it turns out Lutron has 24/7 tech support. That's impressive.

The tech advised me to try switching the COMMON wire with one of the other (non-ground) wires. I did, and it solved the problem.

My only question is, how could the original 3-way switching have worked if the wiring was the way I had it?
 
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Old 08-22-16, 11:46 PM
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The circuit is pretty straightforward. You more than likely have one of the wires switched for the common.

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Old 08-23-16, 07:33 AM
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A wire transposed with the common would cause that issue.
 
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Old 08-27-16, 01:41 AM
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Nice diagram! It's also interesting to see that not one but three kinds of lighting fixtures will work in that setup. :?)
 
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Old 08-27-16, 06:50 PM
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Those are just three terms for a light fixture.
 
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Old 08-27-16, 10:04 PM
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Those diagrams are labeled in three different languages which confuses the issue. I blanked out most of the other two languages and missed that one.
 
 

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