Replacing light switch with dimmer switch

[Sam22]

I'm replacing a standard light switch with a 1 gang dimmer switch. I've managed to get the light to come on/off using the dimmer switch however it won't dim. After reading online I think I've wired it incorrectly first time and broken the dimmer, but just wanting some confirmation from you guys before I go buy another....

This is the original switch wiring, before I started messing:

On the dimmer switch I have L1, L2 and C.

Originally I wired the dimmer exactly the same as the original switch was wired (2 brown wires going to L1 and 1 brown wire going to L2). Tested and this didn't do anything, light didn't even turn on.

Then I moved the single brown wire from L2 to C - Light then switched on/off but did not dim.

Have I wired it right second time, but broken the dimmer by wiring incorrectly first time?

 

[SparkyChick]

Your second attempt at wiring sounds correct (i.e. one side to C and one to L1).

I can't say whether the original connection will have broken it.

Compact fluorescents, certain types of LEDs or low voltage lighting supplied by a transformer cannot usually be dimmed. LEDs and low voltage transformers are available in dimmable versions.

So, what type of lamp are you trying to dim?

 

[Sam22]

Its an LED (E27 fitting) bulb, I bought it with the dimmer and claimed to be dimmable on the box (http://www.diy.com/departments/dial...-1055lm-led-classic-light-bulb/1324553_BQ.prd)

The dimmer also claims to work with LED bulbs

 

[Octopus]

That back box looks very shallow. Is it 16mm ? If so the dimmer might not like getting hot...

 

[Midwest]

That back box looks very shallow. Is it 16mm ? If so the dimmer might not like getting hot...

Optical illusion, the box has 20mm knock outs in it

 

[Sam22]

Its an LED (E27 fitting) bulb, I bought it with the dimmer and claimed to be dimmable on the box . The dimmer also claims to work with LED bulbs.

Back box measures approx 26cm deep.

 

[Midwest]

Not all Lamps and dimmers are compatible. What make of dimmer have you purchased and what Lamp. A company called Varilight manufacture a dimmer that 'seems' to work with most LED lamps.

As Sparkychick said, some dimmers require the load to be connected the 'C' terminal, incorrectly connecting shouldn't have damaged the dimmer, I would not of thought.

VARILIGHT V-Pro Dimmer Series for Dimmable LED Lighting - https://www.varilight.co.uk/dimmers/v-pro.php

 

[shaun1]

It looks like between the old switch and the new switch L1 = C, L2 = L1 and L3 = L2. So the correct wiring should be the 2 Brown wires into C and the single brown into L1 (assuming only one light is controlled by this switch?) Other combinations shouldn't have damaged the switch as long as you only connected brown cables. Getting one of the browns in the wrong place would mean the switch would be controlling other lights on the circuit. This maybe what caused the lack of dimming if there are other fixtures in the house which can't be dimmed. (This is all assuming the wiring follows a standard)

 

[Sam22]

Not all Lamps and dimmers are compatible. What make of dimmer have you purchased and what Lamp. A company called Varilight manufacture a dimmer that 'seems' to work with most LED lamps.

As Sparkychick said, some dimmers require the load to be connected the 'C' terminal, incorrectly connecting shouldn't have damaged the dimmer, I would not of thought.

VARILIGHT V-Pro Dimmer Series for Dimmable LED Lighting - https://www.varilight.co.uk/dimmers/v-pro.php

That's actually the dimmer that I've purchased...! The lamp an LED E27 Diall 11w bulb from B&Q.

Lamp: http://www.diy.com/departments/dial...-1055lm-led-classic-light-bulb/1324553_BQ.prd
Dimmer: http://www.diy.com/departments/varilight-1-way-single-white-dimmer-switch/33047_BQ.prd

It looks like between the old switch and the new switch L1 = C, L2 = L1 and L3 = L2. So the correct wiring should be the 2 Brown wires into C and the single brown into L1 (assuming only one light is controlled by this switch?) Other combinations shouldn't have damaged the switch as long as you only connected brown cables. Getting one of the browns in the wrong place would mean the switch would be controlling other lights on the circuit. This maybe what caused the lack of dimming if there are other fixtures in the house which can't be dimmed. (This is all assuming the wiring follows a standard)

I've tried wiring it exactly as you said (Single brown into L1 and double brown into C) however it's still only turning on/off and not dimming. It's a new build home so I imagine the wiring is all to standard.

 

[Sam22]

I've also just tried the dimmer in another room, where I have all LED dimmable downlights and having exact same problem (turns on/off but won't dim)

 

[Midwest]

Assuming you have you wiring correct, it may be the single lamp is of an insufficient load to the dimmer to operate. I'll looked at the Varilight instructions, and it does not state the minimum load, you could ring Varilight to verify.

You'll see from the dimmer instructions, that it is programmable. It's normally factory set, for trailing edge mode (LED's). You could try a reset of factory settings. Ring Varlight first, to verify minimum load.

 

[Midwest]

I've also just tried the dimmer in another room, where I have all LED dimmable downlights and having exact same problem (turns on/off but won't dim)

It might need that reset, as I said before. I would now ring Varilight for advice. There are different 'Modes' to try. It's normally set to Mode 1. You might just have a faulty dimmer.

 

[Sam22]

It might need that reset, as I said before. I would now ring Varilight for advice. There are different 'Modes' to try. It's normally set to Mode 1. You might just have a faulty dimmer.

Tried the reset but it's difficult to know if it's working as the light is supposed to dim & brighten to let you know it's responding, but obviously mine isn't dimming at all...!! I'll give them a call, thanks.

 

[Midwest]

Tried the reset but it's difficult to know if it's working as the light is supposed to dim & brighten to let you know it's responding, but obviously mine isn't dimming at all...!! I'll give them a call, thanks.

They do suggest;

'NB. It has been noted that some LEDs do not show the programming as well as others. If you are having difficulty seeing the programming steps, you can replace one LED lamp with a halogen one for the duration of the programming in order to see the steps more clearly'.

Not sure if you can do that with one lamp?

 

[Midwest]

Do lets us know how you get on, so we can all learn

 

[Sam22]

They do suggest;

'NB. It has been noted that some LEDs do not show the programming as well as others. If you are having difficulty seeing the programming steps, you can replace one LED lamp with a halogen one for the duration of the programming in order to see the steps more clearly'.

Not sure if you can do that with one lamp?

Yeah I tried switching to a regular lamp but same issue

 

[shaun1]

This would suggest a fault with the dimmer to me

 

[Sam22]

Spoke to Varilight and they confirmed there shouldn't me a minimum load for my dimmer.

Just bought another, exact same dimmer, and now seems to be working fine.

Only question I've got is the lamp don't seem to dim enough to what I could consider 'dim'. Is this just a trait of LED lamps because they're so energy efficient that even the slightest amount of power will make them quite bright?

 

[Midwest]

Only question I've got is the lamp don't seem to dim enough to what I could consider 'dim'. Is this just a trait of LED lamps because they're so energy efficient that even the slightest amount of power will make them quite bright?

Yep effectively, LED lamps need a certain amount of 'power' to work, unlike the old filament lamps. Manufacturers of LED down lights some times give a % rate of possible dimming of their luminaires, with suggested compatible dimmers.

You may also find that if you set the lamp & dimmer too low (minimum diming), the lamp may not come illuminate, when you turn the dimmer back on (the Varilght has a minimum setting mode to prevent this). You could try another make, or another type of LED lamp. But the effect might be the same.

The Diall is B&Q's 'essential range', something like this might work better; 6 Watt - E27 Dimmable LED - Standard Shape Filament Bulb from LED Hut - https://www.ledhut.co.uk/led-bulbs/led-filament-bulbs/6-watt-e27-edison-screw-filament-standard-shape-led-bulb.html but there's no guarantee.