LUTRON RANIA dimmers and 12v track lighting

[pixie6]

Please could anyone help me with this ongoing problem...and if you know a good electrician could you challenge them with the following! :

I have 2 rooms - each with two 12v tracks on the ceiling. Each track has 4x50w spotlights with a Mode 210 Electronic transformer on it. Total load 400w per room. There is a Lutron Rania single non-IR dimmer controlling each room (capacity 500w), and the two rooms feed into a double 2-way normal rocker/toggle switch on the stairs (so that we can turn one set of lights off as we go upstairs and the other set on above us).

The problem is: the Lutron Ranias are not working. Power is going to them because a single green light appears on each of them at the bottom, but they do not respond to the pressing of any buttons, or from the normal 2-way switch on the stairs.

My electrician has tried replacing the Ranias with normal non-dimmable rocker switches and the lights come on fine, and the 2-way switch on the stairs works perfectly too. So it is not a general wiring issue.

It is not a transformer compatibility issue either because I have spoken to a technician at Mode Lighting who make the transformers and they assure me they are correct.

The Lutron Ranias are not faulty because I have tried several different ones.

My electrician wired the system according to Lutron's own diagram for compatibility with non-Lutron accessories. He is therefore completely foxed.

Lutron told him twice that normal 2-way rocker switches should work fine with the Rania - so no need to by the Rania double accessory dimmer for the stairs.

Do you think it sounds like a programming issue? I have tried the programming instructions that Lutron supplied for the Rania dimmer, but still nothing. Maybe they need special programming when they are put with 2-way rocker switches and not the Rania accessory ones. I am getting no joy from Lutron technical support.

Any advice really appreciated.