Swap switch over to a dimmer

BarryT201 · Mar 11, 2023

My daughter is asking me if it’s possible to change her double light switch outside her bathroom to a dimmer.

It’s a 2 gang switch that turns on the lights and the other switch does nothing. I think it’s permanently turned on and powers the underfloor heating programmer, flicking that switch has no effect.

I will also aim to change to dimmer lights.

So what she would like a dimmer switch for the bathroom and some way of also permanently powering the PRT U/F heating thermostat, is a 2 gang switch needed.

Thanks

Dustydazzler · Mar 11, 2023

Both switches look like they are wired up so you need to ideally ascertain what they both do

its hard advice on fitting a dimmer if we don't know what it is dimming

BarryT201 · Mar 11, 2023

99% sure it powers the thermostat and 100% sure it powers the bathroom LED lights. Will need to check the thermostat connection though

brianmoooore · Mar 11, 2023

Is there an extractor fan in this bathroom, and does it work?

BarryT201 · Mar 11, 2023

brianmoooore said:
Is there an extractor fan in this bathroom, and does it work?

Hi. Yes there is and it has a separate power switch for it.

brianmoooore · Mar 11, 2023

Is this switch in a 'normal' position, or somewhere unusual, like high up or hidden away somewhere?

BarryT201 · Mar 11, 2023

brianmoooore said:
Is this switch in a 'normal' position, or somewhere unusual, like high up or hidden away somewhere?

Hi, the switch for the fan looks like a bog standard one and it’s around 3 feet above the light switch in the picture

brianmoooore · Mar 11, 2023

That will be an isolator switch, and is required to be fitted to allow maintenance of the fan. It is intended to remain in the 'on' position all the time, and the switching of the fan will be elsewhere. This could be automatically, such as in response to a humidity sensor, it could use the same switch as the light, switching on with the fan and running on automatically for several minutes after the light is switched off (probably the most common arrangement), OR it could have a separate switch, which I now think is what the second switch is for in your case.
It would be very unusual for the switch to have anything to do with the heating control beside it. Isolation for this would normally be the main isolator for the whole heating system.

BarryT201 · Mar 12, 2023

brianmoooore said:
That will be an isolator switch, and is required to be fitted to allow maintenance of the fan. It is intended to remain in the 'on' position all the time, and the switching of the fan will be elsewhere. This could be automatically, such as in response to a humidity sensor, it could use the same switch as the light, switching on with the fan and running on automatically for several minutes after the light is switched off (probably the most common arrangement), OR it could have a separate switch, which I now think is what the second switch is for in your case.
It would be very unusual for the switch to have anything to do with the heating control beside it. Isolation for this would normally be the main isolator for the whole heating system.

Many thanks for the info. Electrician coming on Monday so will leave him to look into it. Thanks everyone for your input and advice.

Avo Mk8 · Mar 12, 2023

Just to say I believe that (RF) UFH controller (Prowarm/ Heatmiser) is a battery driven module clipped to the wall, and is not mains connected in any way! You can open it up by pushing a small screwdriver in the two slots in the lower edge if you want to check.