Varilight V-Pro dimmer driving LED downlighters - not turning off

[Jon Parker]

Morning all,

I've a new extension which has 2 banks of downlighters (one bank of 6 and one of 8) in the ceiling. Each bank is controlled by a Varilight V-Pro mullti-point touch and IR dimmer master and slave.

When I turn the lights off, they are staying on but going to a really low, barely perceptible level.

I know they aren't turning off properly because if I knock the breaker off they go out properly.

I have faith in the electrician, and everything is brand new.

The LEDs downlighters are dimmable jobs from screwfix, about £9 a pop. I have some of these same downlighters on normal switches and they work fine.

I've tried all three dimming modes on the Varilight switches.

Because it is happening on both banks, I'm inclined to suspect the dimmers.

Anyone out there got any experience of this issue with this product?

Kind regards Jon

[Brian Gaff (Sofa]

Are these those touch plate ones. I think it may well be that the plate is still thinking its been touched due to pick up of interference maybe? I had a table lamp like that some time ago, It did not make filament lamps glow but it did put current through when off. I've never really trusted touch switches. I don't care now of course so all the clever switches are now toggles so I can just put the light on when a sightee comes along. Brian

[Chris Hogg]

Lots of LED lights take time to extinguish after they've been nominally switched off, because LEDs take so little power that any capacitance in the supply will mean the voltages take time to decay. Even induced voltages in the wiring due to running supply cables close to each other may cause the effect. I believe a solution is to wire high-resistance shunt somewhere in the circuit across the LED, that will bring the voltage down sharpish after the lights have been switched off. Someone will confirm the details soon, I'm sure, or not, ATCMB.

[Jon Parker]

No, not true touch control but microswitches. So the switching is electronic, rather than mechanical.

Jon

[Dave Plowman (News]

Does the total load conform to the minimum stated on the dimmer?

[John Rumm]

Are these the push on / push off style or the touch dimmers?

If its a touch dimmer, then it might be that the standby current that the switch needs to draw for its own operation (which it has to do through the load as there is no neutral available at the switch position) is enough to cause the glow.

If its a push type with a mechanical switch, then its likely down to capacitive coupling in the wires (more common on longer runs and two way switched setups).

One way to fix both issues is something like:

[S]

That is probably a dummy load comprising of a resistor and/or capacitor...... :-)

[Martin Brown]

How faint? You can easily see the die illuminated in modern high efficiency LEDs with just a couple of uA flowing in them.

Dark adapted you can see by 10uA leakage current on an LED torch. Makes it much easier to find one in a power cut after dark.

Could also be capacitive coupling of long wiring runs especially if it is a two switch system with them widely separated.

[Dave Plowman (News]

Just looked, and in the notes says not suitable for LEDs that need triac control. But not sure what they might be.

I've got a few of the V-Pro modules and they are fine even with a very low load. But have a normal push on/off switch.

[Andy Burns]

No mention of that in the instruction sheetm but it does mention the glowfix that john reccomended

Yes, same here, not the touch version.

[Brian Gaff (Sofa]

Well its still mechanical then, just momentary rather than toggle,if you like the toggle is electronic. A circuit with hysteresis, like a bistable multivibrator circuit and one of the loads is operating the switch. Brian

[Brian Gaff (Sofa]

Maybe the way ahead is a very low current filament lamp somewhere just enough to make it think its got a load. Brian

[John Rumm]

Which means the load is *not* mechanically switched. So the switch depends on bleeding some current through the load for its electronics to be powered.

[jon]

The start sequence is initiated with a mechanical switch.

[Mathew Newton]

I don't, but I would recommend getting in touch with Varilight's customer support:

They've got a decent ticketing system and the service behind it seems pretty good - they've given me detailed technical advice in the past and are seemingly quite happy to send out replacement modules if a fault is suspected.

Mathew

[John Rumm]

Yup, but that needs powered electronics to respond to it and switch the load. So the switch is essentially an electronic one that needs to be continuously powered to work.

This is different from the Varilight push on / off dimmers. That are completely "off" when the push switch is in the off position, and only run their electronics when they are switched on with the mechanical switch.

The former type (along with touch dimmers) can cause sensitive lamps to glow even when turned off as a result of the quiescent load drawn through the lamp by the electronics. The latter type won't do that, although you can still get a glow as a result of capacitive coupling of the switched live wire to the lamps.

[Jon Parker]

Yes, I am well under that. Blurb says max 10 bulbs / 100 watts per switch. I have a bank of 8 and a bank of 6 each on separate switches. The LEDs are just 5w each, so one switch is coping with 40w, the other 30w in total.

Jon

[Jon Parker]

That looks like it me just the job. Hopefully the supplier will respond in kind to my request for some tech support and suggest the same product. Presumably in my set-up (I have 2 dimmed lighting circuits, one with 6 and one with 8 LEDs) I would need one regulator for each switched bank?

Jon

[Jon Parker]

Thanks Matthew, noted. I have contacted the supplier website of the switches in the first instance.

Jon

[Andy Burns]

But you don't want to be *under* the minimum ...