Electric roller shutters - 2 new switches don’t work the single shutters from 2 switches.

[Mike Greene]

In my house in Spain, I have just replaced 2 switches that controlled a single motorised shutter (the pair of switches in photos - NB, shutters are the middle of the cluster, other 2 being, 2-pin socket and a light switch) on a bed headboard that controlled a motorised window shutter. The originals were single-button sprung rocker (press and hold to engage) switches (up - (sprung back to) off - down). Leroy Merlin’s own ‘Lexman’ brand’s solution was a prewired 2-switch unit where one was ‘up’ and the other ‘down’; each button has an ‘off’. (This is the large switch with diagonal and short horizontal black cable joining things up with other bits of the switch. Despite being physically able to select both up and down at the same time, the circuit prevents this electrically.

My problem is that while I can make one switch on one half of the headboard work exactly as advertised (up, down and stop), the other makes a whining sound and only drives the shutters down (but not up) at a snails’s pace. No circuit breakers/RCDs blow. I thought that this might be a conflict between a switch set to ‘drive’ on one side of the bed while the other was being asked to go the other way but this still happens if the ‘good’ switch is set to,’stop’ on both it’s ‘up’ and ‘down’ buttons.

Question. How can I wire these switches together (incl the schematic from the packaging) to control the single window shutters from either side of the bed - or is this impossible with this design of switch?

 

[Lucien Nunes]

The new switches should be equivalent to the old ones and should work. As I'm sure you're aware, only the up or down line to the motor should be energised from the supply at once. Whichever is not energised will receive a voltage back from the motor capacitor and must be isolated. If up and down become interconnected at either switch location (either the one that is being pressed or the other) the capacitor is bypassed so the motor can't develop any torque, and will make nasty noises and perhaps shuffle round as gravity pulls the blind down

The most likely explanation is that one or other switch is not wired correctly, or is faulty, and is shorting the up and down leads together. I would begin by disconnecting everything, making the six ends safe in Wagos or terminal blocks, and using a simple 1-way switch to identify up and down at each switch location in turn. Once totally confident that I had correctly identified them, and that the motor behaved normally when each of the ups and each of the downs is energised, I would fit one of the proper switches and test, then fit the other and test again.

In a perfect world the two switch locations would be interlocked so that operating one switch breaks the circuit to the other to prevent a conflict, just as the up and down halves of each new switch are interlocked. But I infer from the wiring of the old switches that this is not the case, and there are just supply, up and down leads at each.

 

[Mike Greene]

What a helpful reply - thank you! I will double check everything next tine I’m at the house as you recommend and if necessary exchange the switch if faulty. Oddly, that was an outcome I hadn’t considered!
Mike

 

[marconi]

The picture of the wiring of the switch with '11mm' on the rear looks wrong to me.

I understand (may be wrong then) that it is two switches like the image with the blue and two brown wires shown top right of the image and '11mm' that you want to fix left and right of the headboard and wire together to control the one electric shutter. This switch is actually two switches side by side and I reckon they are each 'double pole double throw'. The common is the L/P terminal and the Normally Open and Normally Open are 1 and 2 (but you need to check which way round is which).

To wire two sets of these switches you need to connect them up according to this wiring diagram. The two UPs are to be paralleled and similarly the two DOWNs - I forgot to note this in the diagram. Also the two Ls are joined together.

The circuit ensures that power P is only applied to say the Down coils when the Up switches Up1 and Up2 are not operated and vice versa.

 

[marconi]

Up = Pup AND (Up1 OR Up2) nb: Pup is Power to Up switches

where Pup = Not Down1 AND Not Down2.

AND = switches in series and OR switches in parallel

So Up = (Not Down 1 and Not Down2) AND (Up1 OR Up2)

from this Logic expression one can draw out the wiring of the DPDT switches noting a NC is a Logic 0/False output and a NO is Logic 1/True output. and the tandem operation of the contacts of a DPDT switch means both NCs and both NOs are always at the same logic state.

Similarly for Down.

 

[Lucien Nunes]

It would be nice to interlock it like that, so that either up switch inhibits both downs, and vice versa, but I don't think those switches the OP are regular DPDT types. Although there are lots of terminal holes, they are almost certainly in pairs and there are only four accessible terminals per switch, internally configured to be wired as per the schematic.

Also, I suspect the existing wiring is drawn in with just the up and down accessible at each point, whereas the interlocking would require cross connections for both N/C switches. To avoid confusion, I would suggest he rewires as before, at least until normal operation is achieved.