Changing two way switches problems

[thefatsnowman]

I've tried to replace a two way switch in my upstairs/downstairs hallway. I can't seem to get it to function correctly.

The setup is: downstairs is a two way, two gang switch. Upstairs is a two way switch. I've replaced the downstairs switch, ensuring that I moved each wire across to the new switch. There are three wires for the relevant gang: red, blue and yellow. The red is in the com, yellow on l1 and blue in l2. The second gang works just fine.

Upstairs, I haven't yet replaced the switch as I'd bought a single way switch by mistake, so it's just as before. Here there are far more wires; 3 red in l2; 2 yellow in l1; 1 blue in com; a blue and a black in an end block.

Currently, each switch can turn the light off and on, provided the other switch is set to 'off'. If the other is on, however, I can't turn it off.

I have tried numerous variations of the above wiring. I harmonised the l1, l2 and com wiring by changing the upstairs switch. That didn't sort it. I tried swapping l1 and l2. That didn't sort it! I've no idea why there are two wires in an end block.

Any suggestions very welcome as it's driving me insane

 

[FrodoOne]

I've tried to replace a two way switch in my upstairs/downstairs hallway. I can't seem to get it to function correctly.

The setup is: downstairs is a two way, two gang switch. Upstairs is a two way switch. I've replaced the downstairs switch, ensuring that I moved each wire across to the new switch. There are three wires for the relevant gang: red, blue and yellow. The red is in the com, yellow on l1 and blue in l2. The second gang works just fine.

Upstairs, I haven't yet replaced the switch

Currently, each switch can turn the light off and on, provided the other switch is set to 'off'. If the other is on, however, I can't turn it off.

I harmonised the l1, l2 and com wiring by changing the upstairs switch.

Why did you replace any switch?
Did the set-up work correctly before you replaced the downstairs switch?

(If it did and you "moved each wire across to the new switch", it may be that the new switch does not have the relevant connections in the same locations - and photos may help.)

While you wrote "Upstairs, I haven't yet replaced the switch" you also wrote "I harmonised the l1, l2 and com wiring by changing the upstairs switch." ?????

How many seperate lights are controlled by these two switches and where are they?

Finally, do you have a multi-meter?

 

[thefatsnowman]

I replaced them because they were old, unattractive and the switch mechanisms somewhat temperamental.

The setup previously worked, so it was for the above reasons. Redecorating, basically.

The new switches (downstairs, for clarity) appear to be identical, save aesthetically. The old and new have com, l1 and l2. When wiring the new switch, I took note of the labels on the original switch (rather than just where physically they were) for each wire and then wired it to the same label on the new switch.

To be clear, the upstairs controls one light. The downstairs controls two, separately (it's a two gang switch). One is the same upstairs light (I.e. 2 way circuit) , the other is a separate downstairs light for which it is the sole switch. That second light functions fine on the new switch.

Yes, I have not yet replaced the upstairs, but when trying to fix the issue I've set out, I'd tried various combinations to see if I had simply wired downstairs wrong. Currently, it is set up exactly as described above, I. E the upstairs as it always has been, and downstairs is the same wiring configuration of the old switch, but with the new switch in situ.

I will see if I can dig out a multi meter (I used to have one!)

 

[FrodoOne]

To be clear, the upstairs controls one light. The downstairs controls two, separately (it's a two gang switch). One is the same upstairs light (I.e. 2 way circuit) , the other is a separate downstairs light for which it is the sole switch. That second light functions fine on the new switch.

I asked "How many seperate lights are controlled by these two switches and where are they?

Your reply indicates that there is only one light controlled by the two two-way switches.
The fact that there is an additional switch controlling another light is irrelevant to your problem, as you have indicated by writing "That second light functions fine on the new switch", which is one of a pair.

(The question was asked because of the multiple wires involved at the upstairs switch.)

How is the other downstairs switch "fed" relative to the two-way next to it? This is asked because it must be switching a Line wire (probably Red) and it would be of interest to know the relationship of that wire to the adjacent (two-way) switch - which is why photos would also be of assistance.

 

[ban-all-sheds]

When wiring the new switch, I took note of the labels on the original switch (rather than just where physically they were) for each wire and then wired it to the same label on the new switch.

Did you make sure that you considered the way that each set of COM/L1/L2 was grouped, i.e. which particular COM/L1/L2 were all in the same gang? Different switches can lay them out differently on the rear.

I will see if I can dig out a multi meter (I used to have one!)

You are going to need one, unless you want to get an electrician, as basically you have to choose between Plan A and Plan B.
PLAN A:

• Learn how lighting circuits are wired.
  • //www.diynot.com/wiki/Electrics:Lighting
  • http://wiki.diyfaq.org.uk/index.php/House_Wiring_for_Beginners#Lighting
    
  • http://www.google.co.uk/search?q=uk+lighting+wiring+(basics+OR+101)
  • //www.diynot.com/wiki/Electrics:books
  • //www.diynot.com/wiki/Electrics:index
• Find your multimeter.
• Identify which conductors are which at the switches and the light positions.
• Work out what should go where and connect everything up properly.

PLAN B:

• Get an electrician.

Please stop trying different things without really knowing what's going on, hoping to get it working by luck, or by blindly following instructions to put-this-wire-in-that-hole without any idea as to why, even if that's misguidedly suggested by someone here. You must know what, and truly understand what, you are doing.

Electrical-installation-by-guesswork is a foolish idea.

 

[AndyPRK]

if your trying combinations.

Put the blue in COM (as that is what it is upstairs)

And the red and yellow into L1 and L2 (doesn't actually matter which way round)

 

[thefatsnowman]

Thanks for the comment.

Yes, I did ensure I was clear which wire related to which gang downstairs. As the second gang operates correctly, I assume that is correct.

I also do have a reasonable understanding of the lighting circuits, and did historically study electronics such that I was more than comfortable with the basics. I wouldn't have attempted it this otherwise. Memory fades a little, and I don't so this kind of thing regularly, but I do understand the principles still. I can certainly read a circuit diagram.

Which is why I don't entirely understand how, having been wired up identically which would logically dictate the relevant circuits are correctly wired, it does not work as a 2 way switch ought to.

However I accept I do need to sit down with a multimeter and piece of paper to work it out, but I thought I may have made a sufficiency obvious mistake.

 

[winston1]

You said.

I also do have a reasonable understanding of the lighting circuits,

But you also said.

I've no idea why there are two wires in an end block.

It seems you don't have the understanding you claim.

 

[FrodoOne]

Photos please.

 

[securespark]

What he said!!

 

[ban-all-sheds]

Including the back of the old switch

 

[thefatsnowman]

Including the back of the old switch

That I do happen to have to hand on my phone. The rest I can do when I get in.

 

[ban-all-sheds]

From memory, what was the layout of the back of the new switch?

 

[thefatsnowman]

For each gang, which sit side by side, 'Com' top left, nothing top right, 'l1' bottom left, 'l2' bottom right.

 

[FrodoOne]

It is 'interesting" (and frustrating) that the OP has not yet answered the question of "How is the other downstairs switch "fed" relative to the two-way next to it? This is asked because it must be switching a Line wire (probably Red) and it would be of interest to know the relationship of that wire to the adjacent (two-way) switch - which is why photos would also be of assistance."

And still no photos, nor any other description, from the OP who is (supposedly) seeking assistance.