Dimmer switch is not dimming

The power supply for the led's may not be dimmable. Not sure if this dimmer is for led but I assume that's why you bought it.

We are truly sorry for your inconvenience and want to help. Please call our Technical Support line at 1-888-523-9466 and we'll be happy to discuss the issues with you.
Craig, Lutron Technical Support Leader

These in-wall devices stop working and need to be replaced from time to time.
There are no repair parts.
Generally dimmers don't last as long as ordinary light switch, because they are electronic instead of mechanical.

Lutron makes the widest selection of dimmers.
http://www.lutron.com/Products/StandAloneControls/Dimmers-Switches/Pages/DimmersSwitches.aspx

Use link above to identify dimmer.
For example Skylark dimmer.

Then google search for a replacement.
For example: single pole 600 watt lutron skylark dimmer
Or: 3-way 600 watt skylark dimmer
Lutron also makes 1800 watt dimmers for larger loads.

Add a comment any time if you need more help.

You can also take advantage of fixya phone service.
Fixya expert will talk with you via phone for a price.

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.

There are no repair parts for in-wall electrical devices.
When they go dad you buy another.
Lowes and Home Depot carry inexpensive dimmers.
Look for 3 things:
1) Wattage: most off-the-shelf dimmers are 500-1000Watts. Add up total wattage.
2) If you are dimming incandescent bulbs, dimmer package will say tungsten or incandescent.
Package will say florescent if dimmer also works for florescent bulbs.
3) If dimmer is 3-way, with a dimmer on either end of a room, many times the dimmers are sold as a package of 2 dimmers with 1 dimmer that controls the other dimmer.

Lutron dimmers
http://www.lutron.com/Products/StandAloneControls/Dimmers-Switches/Pages/DimmersSwitches.aspx
Leviton dimmers
http://www.leviton.com/OA_HTML/ibeCCtpSctDspRte.jsp?section=15265&minisite=10025

As a general rule, grounding will not affect operation of dimmer.
Type of dimmer, type of switch being replaced, type of load, and how you connect wires will affect dimmer.

Here is Lutron dimmer switch page
http://www.lutron.com/Products/StandAloneControls/Dimmers-Switches/Pages/DimmersSwitches.aspx

What is the load? Are you wiring dimmer to a ballast? Or fan? Or incandescent lights? Or florescent lights?
Are you replacing a 2-way or 3-way switch?
What color are your dimmer wires?
How many wires were connected to switch?
Can you re-install the switch, and know where each wire went?
Did you replace a light with a fan, and then want the dimmer to slow the fan? Not every dimmer will work with a fan, or florescent lights.
Dimmers cannot dim LED lights.

If I know what type switch you are replacing, and the type of load you want to control, and the specific dimmer you have, I can answer the question.

There is one more thing that you can try, turn the power off from the breaker and wait about 20 seconds, then turn back on. If that doesn't fix it you are probably right about the dimmer being bum. It is very rare that Lutron devices are defective. You can contact them directly and see if you can get it replaced since you no longer have the receipt. You may have to send it to them before they will send you a replacement but it beats spending another $50
http://lutron.com/CMS400/page.aspx?id=24679

The Lutron Maestro dimmer isn't rated or designed to operate low voltage lighting as it is a 120 V-AC rated electronic dimmer. You should either install a standard low voltage ON/OFF switch on this installation or obtain a dimmer rated for use on low voltage lights.

You need special low voltage dimmer designed for use on the low voltage pucks lights you have installed. Usually the low voltage is either 12, 24, or 36 volts, depending on the manufacturer of your particular light set. Once the correct dimmer is in place, the problem with the flickering and pulsing of the lights, should cease.

If you still are having this problem and you can't find a low voltage dimmer, you can contact the maker of your low voltage light kit and they can provide you with an acceptable dimmer option for your lights.

Most Home Depot and Lowe's carry the low voltage puck light kits, and usually have accessories for these lights, including dimmer switches that will work with them.

Hope you find this Very Helpful and best regards!

PS: I found this old, unanswered question and wanted to provide a solution to close out the problem and clear the question from the site.

What is the dimmer rated for? Your load on the track appears to be 200 watts. A standard dimmer will burn out, you need to look on the dimmer to see what it is rated for. Did it run hot with the dimmer before you had this problem? They make dimmers for higher wattage that will do the job for you.