Wiring for 2-Way & Off Retractive Switch

[MattJW]

Hello, I have a skylight connected to an old style 2 gang retractive switch - 1 switch held for up and other switch held for down. I am replacing it with a new Varilight 1 gang 2-Way & Off Retractive Switch XDSR1S (https://www.varilight.co.uk/configurator/product.php?code=XDSR1S).

The current wiring in back box consists of:

Cable 1. Blue, red, yellow and earth
Cable 2. Black, red (split in box into a red and yellow) and earth

Wiring to existing switch (photos) is:

A. Blue (1) and black (2) together to bottom terminal
B. Red (1) to one side terminal
C. Yellow (1) to other side terminal. On same side (separate screw but possibly same terminal) both red (2) and yellow (2).
D. Earth (1 and 2) connected to back box

Grateful for guidance on which wires should connect to L1, L2 and COM terminals of new switch. Understand that earth needs to connect to metal faceplate and then back box. Thanks

 

[mikeyd]

It's only a guess, but I would think the single yellow and red wires would go to L1 and L2 on the new switch, and the red/yellow that are together would go to COM.
Then the blue/black would be connected in a bit of terminal block, not to the switch.
HOWEVER. The old switch has an "Integrated Shunt" and I don't really know what that is. Possibly some way of limiting the current when the skylight gets to the end of travel so it doesn't burn the motor out?
That and the fact the old switch has neutral connected to it makes me think it might not be a straight swap.
Hopefully someone who knows about these things will have some better advise.

 

[MattJW]

Thanks mikeyd, that worked perfectly. The switch works exactly as intended and same as previous switch did. The integrated shunt did not operate as an automatic off switch previously so no change there. Thanks again!

 

[bernardgreen]

The integrated shunt did not operate as an automatic off switch previously so no change there

The "shunt" may operate only if the switch is held ON for a prolonged period after the motor has stalled. This protects the stalled motor from becoming overheated

Normally the motor would stall only when the blind is at the end of travel. In this case the human would release the switch.

If the blind jams mid travel and the human holds the switch ON to try and move the blind then without some form of protection the motor may overheat,

 

[MattJW]

Thanks, that’s good to know. Appreciate the effort to respond.