Dimmer switch with a neon indicator, or ?

[colinM50]

Fitted a central air handling fan extractor thingy in my loft with trunking going to the bathrooms and bedrooms which I'm hoping should solve the condensation issue.

The plan is to leave the fan on very low during the day and then when we use the showers turn it up a bit to take out the steam and then switch it off at night or as needed. So I've wired it through a dimmer switch and it all works remarkably well. The only problem is that I've done it too well and can't easily hear the fan working so I'm not sure if it's on or off.

Now if it was an ordinary on-off switch I could get one with a neon indicator which would show it's status, but I don't seem to be able to find a dimmer switch with an integrated neon light. Auntie Google doesn't seem to be much help so has anyone seen one or know how I can wire an indicator light in? I've only got a live switched cable going to the existing dimmer, no neutral cable at the switch.

Any ideas please chaps? And chapesses of course.

 

[AndyPRK]

Maybe add a neon on the landing ceiling in an enclosure.

 

[Taylortwocities]

I'm not sure if a neon with strike properly, or at all when the dimmer is turned down. It may need to full monty to work. And neons do get unreliable over time.

You may have more sucess if you installed a small LED indicator, but you would need to find a mains one, or engineer it to work with 230v AC….

 

[deadshort]

If you use a 15w pygmy lamp it will also indicate the speed of the fan !as well as on

Kind regards,

DS

 

[JohnW2]

Now if it was an ordinary on-off switch I could get one with a neon indicator which would show it's status, but I don't seem to be able to find a dimmer switch with an integrated neon light. Auntie Google doesn't seem to be much help so has anyone seen one or know how I can wire an indicator light in? I've only got a live switched cable going to the existing dimmer, no neutral cable at the switch.

No-one seems to have pointed out that, unfortunately, without a neutral at the switch, you will not be able to get a neon or any other sort of indicator to work as you wish (not even if it were an 'ordinary on-off switch). Also, even if you could get the neutral from somewhere on the circuit, as TTC has said, it's uncertain (probably doubtful) that a neon would work when the dimmer was turned down low. Given a neutral, deadshort's idea of a small pygmy lamp would also work, but it may become too dim to see that it's on at low dimmer settings.

Kind Regards, John

 

[deadshort]

As Andy has already suggested, if the indicator is in the ceiling i would assume you could pair the lamp with the fan feed.

Kind regards,

DS

 

[AndyPRK]

Should you want an led pack you could get one of these.

Basically 3 3mm surface mount leds in a pack.

red or green

http://www.ebay.co.uk/itm/legrand-S...al_Electrical_Fittings_MJ&hash=item4ad71fb15e

 

[JohnW2]

As Andy has already suggested, if the indicator is in the ceiling i would assume you could pair the lamp with the fan feed.

Indeed - I was obviously talking about indicators at the switch. However, I remain doubtful that a neon would work, or that a low-wattage incandescent lamp/bulb would necessarily be visibly on at low settings of the dimmer. Whether the dimmer is leading- or trailing-edge, the peak voltage will fall to below the striking voltage of a neon if the dimmer is turned down low enough.

As TTC implied, the best solution would probably be an LED with a very wide range of input voltages - but that would almost certainly have to be 'custom engineered' if one wanted it to work down to very low dimmer settings.

Kind Regards, John

 

[333rocky333]

I cant recall the make or the function of the indicater but there are dimmers with lights on and i dont recall there being a neutral connection.
It was white plastic and 1000 watt on a single plate, i brought it in london somewhere to replace a failed unit and it was the only type they had in stock
not much help really

 

[JohnW2]

Should you want an led pack you could get one of these. ... Basically 3 3mm surface mount leds in a pack. ... red or green ...http://www.ebay.co.uk/itm/legrand-Synergy-7301-58-Electronic-LED-Power-Indicator-pack-GREEN-/321436758366?pt=UK_DIY_Material_Electrical_Fittings_MJ&hash=item4ad71fb15e

Those are designed for 230V use and may have no more sophisticated current control than a simple series resistor. If that's the case, they would get extremely dim, probably too dim to see, at low peak supply voltages (low dimmer settings).

What is needed is a constant-current driver for the LED which gives the same current for input voltages from 230V down to very low - easy enough to produce but, as has been said, would very probably have to be custom engineered.

Kind Regards, John

 

[AndyPRK]

I think we all know neons, bulbs and that led pack will give a dim or off output at low fan speeds.

Depends what the OP requires or expects

 

[JohnW2]

I cant recall the make or the function of the indicater but there are dimmers with lights on and i dont recall there being a neutral connection. ... It was white plastic and 1000 watt on a single plate, i brought it in london somewhere to replace a failed unit and it was the only type they had in stock ... not much help really

Unless they used earth as the return path (which would be naughty, particularly if there were RCDs around!) , it would be impossible to have an indicator which came on when the light was on if there is no neutral available. Also, even with a neutral, unless the dimmer provided an 'undimmed' (but switched) output for the purpose, there would be the problem discussed above relating to whether the indicator would work at low dimmer settings.

Kind Regards, John

 

[JohnW2]

I think we all know neons, bulbs and that led pack will give a dim or off output at low fan speeds.

Indeed.

Depends what the OP requires or expects

Maybe I misunderstood, but I thought the OP wanted a visual indication of whether the fan is on when its running sufficiently slowly (ii.e. 'very dimmed') that it can't easily be heard - the very same situation in which the neons/bulbs/whatever will either fail to illuminate at all or be very dim. As I've said, I suspect that the only ideal solution would probably be an LED with 'true' constant-current drive circuitry (i.e. constant current output over a very wide range of input voltages).

Kind Regards, John

 

[AndyPRK]

Light timers get their neutral from a feed thru the lamp, so don't see why a neon couldn't. If such designed it could have a seperate contact to drive the light.

 

[333rocky333]

I cant recall the make or the function of the indicater but there are dimmers with lights on and i dont recall there being a neutral connection. ... It was white plastic and 1000 watt on a single plate, i brought it in london somewhere to replace a failed unit and it was the only type they had in stock ... not much help really

Unless they used earth as the return path (which would be naughty, particularly if there were RCDs around!) , it would be impossible to have an indicator which came on when the light was on if there is no neutral available. Also, even with a neutral, unless the dimmer provided an 'undimmed' (but switched) output for the purpose, there would be the problem discussed above relating to whether the indicator would work at low dimmer settings.

Kind Regards, John

It was plastic and no earth, i recall it well as pub work entails lots of dimmers and the manager liked it as he could tell it was on even though the walllights or whatever were out of site, im pretty sure it dimmed in conjunction with the dimmer
proberly came rom Ryness