We have the older style (15 years old) master/slave Leviton Mural dimmer switches in our home controlling 4 different sets of lights. I woke up this morning to find NONE of the them working. All of the masters have power and level lighting and they are separate circuits. How do I reset them? No apparent issues otherwise in the house regarding fixtures, etc.

Leviton 6161 is shown on Leviton as 500 watt incandescent-only 4-level dimmer that cannot control a fan.
If this is a ceiling fan and light, then search for fan light dimmer, or fan control,

If this is bathroom fan-light installation, you are needing a countdown timer rated for both bulb and fan... which will require Neutral wire...
Different timer choices with manuals appear following link:
http://waterheatertimer.org/Countdown-timer-horsepower-ratings.html#Leviton

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Guessing you have 3-way switch where 2 different switches control same Load (light, fan, motor). Unknown wiring, and unknown if fan and light are wired separately.

2) Google search for 3-way fan switch shows Leviton IPF05 with simple straight-forward wiring. Link below has instruction manual, and Live chat button located to right of LEVITON
http://www.leviton.com/OA_HTML/ProductDetail.jsp?partnumber=IPF05-1LX&section=47082&minisite=10251

3) It appears that the Leviton device must replace Line side switch.
http://waterheatertimer.org/images/GE-15312-3-way-circuit-600.jpg

4) Uncertain if this device also controls fan since the wiring is so simple.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Wiring is unclear without more information.

Question posted under 4-way switch.
Wiring sounds like 3-way switch is possible.
And Leviton 5601 is single pole switch.

Add a comment and say what load the switch controls. Load means light, fan, motor, etc.
Say if another switch controls same load.
And include what type of device you are replacing.
Include what screws and screw colors are on old device.

When you add a comment, it sends email, and I will respond to comment.

You posted under Leviton rotary dimmer.
Lutron and Leviton have many 3-way dimmer styles, and both make 3-way rotary dimmers.

I remember years ago replacing 3-way switches with dimmers and having same experience as you. One dimmer has to be ON for the other dimmer to dim.

Later I learned when you replace both 3-way switches with dimmers, you buy a control-and-companion dimmer set. One dimmer is main, and it lets you dim from both locations. The two dimmers communicate with each other electronically. Buy these dimmers at lighting store that specializes in fixtures and dimmers. Ask for most experienced salesperson.

I checked to see if rotary dimmers are made in the companion set. And neither Leviton or Lutron show 3-way companion set rotary dimmers.

1) Leviton spec sheet on rotary 3-way dimmers does not show companion dimmer. This indicates that Leviton rotary dimmers don't have capability of communicating with each other.

2) Lutron has image of 3-way rotary dimmers.
Image shows single rotary dimmer in 3-way & 4-way circuit.
This tells me that Lutron does not have companion dimmer for 3-way rotary dimmer.

http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=4044§ion=10103&minisite=10025
The Leviton page for Leviton 5613 does not have a troubleshoot.
Manual shows simple wiring diagram.
3-way switches will not operate lights if switches are wired incorrectly.
Check your ground wire is connected.
Leviton 5613 series is illuminated.
Check that both switches have 5613 number.
Swap switches and see if problem is inside switch.

The problem is most likely not the dimmer or the wiring, but rather the existing 3-way switch.

First of all, the Aspire smart dimmer does not work in conjunction with traditional, 3-way, on/off toggle switches. When the 3-way switch is in one-position, it lets the dimmer work, but in the other position, it cuts power to the entire lighting circuit - and the smart dimmer is NOT going to be able to override that. You instead need to get the corresponding remote dimmer (sometimes called a slave, or a companion dimmer), and use that to replace the standard 3-way switch.

That may also solve your "mystery turn-on" issue. Even though those dimmers can use the existing 3-way switch wiring, you have to REALLY pay attention to the instruction sheets to see how the master and the slave wire up to each individual electrical box. I vaguely remember that even if you were to use the product in a single-pole application, those two wires that, I assume, you attached to the traveller wires in the house needed to be shorted together in order to work - and since you have them running into a 3-way switch, the errors that you're seeing are bound to happen.

Long story short, get the slave dimmer, install it according to the instructions, and all these problems should go away.

I have never heard of master and slave 3 way switches. Both switches have to be 3 way or it will do just what you describe. The white traveler wire has to go from switch to switch, It is a nightmare to figure out sometimes, depending on what is being switched. I have seen electricians walk away from their jobs over 3 way switches. If you get a new switch, the instructions are in the box. Hope this helps.

If each pendant has an individual transformer that is about the size of a hotwheel then you need a dimmer specifically for ELECTRONIC LOW VOLTAGE. A lot of electricians don't know that the different types of lights require different dimmers. Most store bought dimmers are for incandescent lights only, and some nicer dimmers like the Lutron Maestro's are rated for incandescent or MAGNETIC Low Voltage which require a different Sin wave interuption. I don't know that leviton makes a dimmer in that style for Electronic Low Voltage. You could install a Lutron DVELV300P-Wh, but that is a Decora opening. http://www.lutron.com/CMS400/WorkArea/downloadasset.aspx?id=25437
Here is a link to explain the difference in how the dimmer needs to work. Good luck!

I recently purchased a Leviton Dimmer switch which has a brown lead. This switch is to replace 1 of 2, 3 way switches that control the ceiling light in my kitchen. My problem is the new dimmer switch has 4 leads including a brown one which has me confused. I have installed and replaced numerous dimmer switches without difficulty. Please help.

I got one from Home Depot about a year ago...........check there - they have lots of different types of switches.