3-way dimmer switch replacement

[sjchapman]

Bit of advice needed...

Living room - 3 way dimmer switch. A couple of the knobs were slipping off (too loose) and when you turned the knobs they were slipping and not actually dimming the light.

Size of dimmer unit: 150mm x 90mm (standard size I hope)

Operates:

wall lights | one set of ceiling spots (8) | another set of ceiling spots (7)

There is another light switch at the other end of the room (not a dimmer just a standard on/off - pic attached) that turns off one set of the spotlights (dining area). I hope this doesn't make things more complicated!!

Anyway, as the knobs are always slipping off I put a little super glue onto the inside of them and attached them back on the inside of the switches. Problem is when I pressed down some of the superglue went onto the shaft of the switch and now they're sticking and difficult to switch on and off (I know, I know)

They've always been a bit temperamental and not smooth and I want to replace them.

The spots are all 4w LED energy efficient ones and I think the dimmers might be 400w or something, so they can flicker when turned right down and dont dim as much as the old school halogen bulbs.

Question 1: Is it just purchase a standard like for like and replace?

Question 2: I tackle a fair bit of DIY but always leave electrics to a sparky. I've replaced a couple of simmer dimmer switches like for like but when I opened the cover it was a lot more complicated

Question 3: If I'm not comfortable with changing it due to the amount of wiring how much would a local qualified sparky charge for such a simple change? I would imagine its a 15 minute job, I just hope the fact that the switch up the other end of the room that turns off one set of the ceiling spots doesn't complicate it?

Lastly, it was a bit difficult to tell if the lights were actually on or off or just turned right down - if there's no buzzing from the unit and (OBVIOUSLY) the lights are off, then should all be safe when we go to bed?

Thanks in advance

 

[stillp]

Just to get the terminology right - that's not a three way dimmer, it's three-gang, at least one of the gangs being two-way.

 

[sjchapman]

on the https://www.niceic.com/householder/find-a-contractor- site, there's quite a few sparkys just around the corner from me.

If I supply the unit and they just connect - like for like - how much do you reckon?

They could do it when convenient way home from work or weekends so not like it's giving up half a morning or anything

 

[sjchapman]

Just to get the terminology right - that's not a three way dimmer, it's three-gang, at least one of the gangs being two-way.

Cheers mate....I can't rename the thread other wise I would!

 

[sjchapman]

Do they come in standard sizes? hope fully 150mm x 90mm is just that. I was looking at something like this (link below) or should I just ask the sparky to spec it up?

All wiring is fine and only about 5 years old (from when extension was done) so I'm hoping its just the facade front bit that needs replacing.


- fhttp://www.qvsdirect.com/excel-polished-chrome-3-gang-2-way-400w-push-dimmer-light-switch utm_source=google&utm_medium=googleshopping&utm_campaign=googlebase&gclid=CjwKEAiAo7C2BRDgqODGq5r38DsSJAAv7dTPXv68tzRs6zu71CsB_Kdt9guEcYxL_otkjFNo6lRgCBoCHVLw_wcB

 

[Taylortwocities]

The spots are all 4w LED energy efficient ones and I think the dimmers might be 400w or something, so they can flicker when turned right down and dont dim as much as the old school halogen bulbs.

That is because the dimmer is not suitable/not compatible with LED lamps. This is a tricky problem, if you aren't careful.
Most dimmers need a minimum load as well as having a maximum load. For LED lights you'll need a low-watt, dimmer similar to this
https://www.tlc-direct.co.uk/Products/VLJQP303W.html

If you are thinking of getting in an electrician, anyway, I would have him supply and fit the dimmer, then it is his problem to make it work

 

[sjchapman]

The spots are all 4w LED energy efficient ones and I think the dimmers might be 400w or something, so they can flicker when turned right down and dont dim as much as the old school halogen bulbs.

That is because the dimmer is not suitable/not compatible with LED lamps. This is a tricky problem, if you aren't careful.
Most dimmers need a minimum load as well as having a maximum load. For LED lights you'll need a low-watt, dimmer similar to this
https://www.tlc-direct.co.uk/Products/VLJQP303W.html

If you are thinking of getting in an electrician, anyway, I would have him supply and fit the dimmer, then it is his problem to make it work

That's because when we moved in they had halogen spots - I then replaced them with energy efficient 4w LEDs but haven't replaced the dimmer yet.

To get around the flicking on the wall light I've had to leave one old school 40w e14 bulb to knock up the minimum wattage on that run.

The only reason I wanted to get the switch myself is so nobody put a mark up on it or tried to fob me off with a £50 one when it looks like I can get them for about £25 online

 

[ericmark]

Really you should not dim halogen lamps I know many do though. As said with LED lamps then a lower wattage dimmer is required. There are two ways to work a dimmer with two way switching the third wire can be mains or it can be a data link the latter allows dimming to be set from either switch. To get 3 dimmers which you know will work with LED you may need to use a grid switch the dimmer unit is separate to switch plate and clips in

the units tend to be expensive but you can mix and match so one dimmer and one standard on/off can be on the same plate. Typical trade price is around £25 per dimmer plus the plates.

You need to know if the bulbs need trailing edge or leading edge dimmer switch likely a trailing edge. Also of course the load. In real terms dimmer switches are a pain, and all mine have now been removed. When the dimmer also changed the colour to a red glow then they gave the ambiance required, but the LED stays the same colour so there is no warm ambiance any longer.

 

[bernardgreen]

When the dimmer also changed the colour to a red glow then they gave the ambiance required

You can still buy incandescent lamps and get that warm glow. And the heat they "waste" ( in winter ) reduces the amount of gas used to heat the room.

LED lamps can only be dimmed properly by a current source of smoothed DC current that can vary the current in response to a control input.

 

[ericmark]

Yes you can get some odd effects taking a photo in dimmed LED light. Looks like banding as the LED flashes as the focal plain shutter scans the scene.

 

[sjchapman]

Blimey - didn't think it was so complicated. Thought it was just a like for a like but maybe with lower dimmer wattage...all the wiring is fine and nothing needs doing as all works fine me so shouldn't be a big job? Just a like for like?

There's no danger in using lower wattage LEDs that are too low combined (8 X 4w) in my case for the dimmer switch is there?

I changed all 48 halogens in my gaff to LEDs as cheaper to run and safer as don't hear up so much?

 

[Taylortwocities]

It's not complicated, providing you know what to do! But there are a number of variables.
My advice would be to go to the website of the maker of the LED lamps, they usually have a list of compatable dimmers.

Another gotcha is re

There is another light switch at the other end of the room (not a dimmer just a standard on/off

some dimmers will not work with this type of switch, they need a specific "slave" dimmer at the other end……

The V-Pro that I linked to above (#3) doesn't have this issue, but some of the touch dimmers, Crabtree, Doyle & Tratt, Retrotouch, etc will only work with their own specific slave at the other end…

 

[sjchapman]

Sounds a nightmare and would deffo need a sparky to source the right dimmer..

the superglue has dried now and flaking off now I've de-pressed the knobs a bit so I'm hoping I wont have to bother... sounds a load of hassle and £££s

 

[ban-all-sheds]

LED lamps can only be dimmed properly by a current source of smoothed DC current that can vary the current in response to a control input.

Or by a controller designed to work with a PWM driver.

 

[bernardgreen]

Or by a controller designed to work with a PWM driver.

A PWM driver controlling current through the LED element requires adequate smoothing of the pulses of current into smooth into the average current. If the smoothing is in-adequate then the brightness of the LED will vary rapidly at the PWM frequency. There will be pulses of bright light separated by periods of dark.

The eye does not smooth the light but retain the peak brightness so the LED will appear to be brighter than it it should appear.