Replacing a double light switch for a double dimmer switch

[b1guk]

I want to replace the two way light switch in my front room for a two way dimmer switch. In my front room are two seperate switches, one is a single switch that controls the left ceiling light the other is a double switch, one side controls the left ceiling light, the other controls the right ceiling light.
Here is the problem I have. I have taken off the double light switch and wired the double dimmer switch exactly how the original double switch was wired. But this doesn't seem to work correctly. Only one ceiling light will work (the one that can only be controlled from the double switch).

Here is how the original double switch was wired.
on the left side of the double switch RED=L1, BLUE=L2, BLACK=COM.
on the right side of the double switch RED=L2, YELLOW=COM.

Does anyone know how I can sort this out please?

 

[securespark]

Altered any wiring to the ftgs or the other switch?

What is the wiring like in the other switch?

 

[RF Lighting]

I think you have made a mistake there.

Did you assume that on the old switch, the line of terminals across the top of the browm bit at the rear was for one switch, and the row of terminals across the bottom was for the other switch?

Are there just two cables at this switch? One being a three core and earth, and the other being a twin and earth cable?

 

[b1guk]

Thanks for your swift reply. I've attatched a link for some images that I have taken of the current wiring. And yes I did assume that the top row of wires was for one side of the switch and the bottom row was for the other.

IMAGE 1:

IMAGE 2:

IMAGE 3:

Image 1 2 and 3 are of the current switch and wiring which is working fine.
RED=L1, BLUE=L2, BLACK=COM.
RED=L2, YELLOW-COM.
-------------------------------------------------------------------------------------
These next images are of the new dimmer switch. I tried wiring the dimmer switch in the same way as the original switch but it just won't work correctly, and that is why I have put the old switch back. I hope this is a little more clearer. Cheers.

DIMMER FRONT:

DIMMER BACK:

 

[ColJack]

wow... big pictures...

see the diagonal line on the back of the switch?
that divides the terminals into 2 switches..

the red and blue opposite the yellow are 1 switch, and the black opposite the red is the other.

the yellow wire goes to the ~ on one dimmer, with the red and blue that are oposite it into the L1 and L2 of the same dimmer..

the other dimmer has the black into the ~ and the red opposite it into the L1.

 

[securespark]

They are rather large!!

How are the conductors arranged in their respective sheaths?

I guess that there is a twin & earth with red & black in and a three-core & earth with red, yellow & blue in.

If indeed the yellow is common (this can be checked at the other switch), then on one set of switch terminals you connect the yellow to Common and the others to L1 & L2 of the same switch.

The other pair of wires connect to Common & L1 of the other switch.

But you may need that infamous DMM to id the conductors.

 

[securespark]

D'oh!

 

[b1guk]

Many thanks ColJack, makes a whole lot of sense now that you've explained it (what a div am I?) I'll give it a try when I get home from work tomorrow and let you know how I get on.
Your a top man.

 

[b1guk]

Many thanks ColJack, your advice worked a treat, now the misses can stop having a nag. LOL