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Frequently asked questions

Answers to the questions customers ask us most, from choosing and fitting a dimmer to curing flicker. Search, or browse by product or topic.

Showing 10 questions about Transformers and drivers Show all questions

Choosing a dimmer

Which dimmer suits your lights, how much lighting it can take, and dimming from more than one switch.

My LED driver says "triac" or "leading edge": which dimmer do I need?
  • Triac or leading edge: choose V-Com, designed for LED lighting that needs leading-edge (triac) control. V-Pro dimmers are not suitable for triac dimmable drivers.
  • Trailing edge: choose a V-Pro dimmer.
  • 1-10V: choose an F-Series 1-10V dimmer.

If you are unsure which control your lamps need, check the lamp or driver manufacturer's data sheet, or ask us for advice: send us a message or email help@varilight.co.uk.

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How do I work out the dimmer load when there are transformers in the circuit?

Add up the VA ratings of the transformers, not the wattage of the bulbs. Choose transformers with a rating close to their lamp load, e.g. a 50VA, 60VA or 70VA transformer for a 50W low voltage bulb.

  • VARILIGHT transformers: any number, as long as you keep within the maximum rating of the dimmer. For YT40DC12 and YT40DC24 LED drivers, never more than 250W per dimmer circuit.
  • Other brands: use only fully dimmable electronic transformers, and no more than 5 per dimmer circuit.
  • V-Plus dimmers (recommended for halogen on VARILIGHT transformers): load to 75% of the dimmer's maximum.
  • Transformer specifies triac dimming: use a V-Com dimmer.

Wire-wound or toroidal transformers are not suitable for V-Pro, V-Pro Multiway, V-Pro Multi-Point, V-Pro Smart or V-Dim dimmers. If your transformer does not say that it is dimmable it is unlikely to work with any dimmer.

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Can I dim 12V LED lamps or LED strip?
  • 12V a.c. LED lamps (e.g. MR16): use a VARILIGHT YT50LZ transformer up to 25W, or YT70LZ up to 35W. Our transformers take a.c. LED lighting at half their full rating.
  • 12V d.c. LED: use the YT40DC12 driver, up to 40W of LED strip or 30W of LED lamps.
  • 24V d.c. LED: use the YT40DC24 driver, up to 40W of LED strip or 30W of LED lamps.

The dimmer goes on the mains (input) side of the transformer or driver. For LED strip choose a V-Pro dimmer, with no more than 250W of drivers per dimmer circuit. See dimmable transformers and the 12V and 24V driver instructions (PDFs).

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Fitting and wiring

Wiring 2-way and multi-way circuits, wall box depths and where to find the instructions. If in doubt, consult a qualified electrician.

Dimmers

Where can I find the instructions or a wiring diagram for my product?

The instruction leaflet, with its wiring diagrams, comes with your product. You can also find every current leaflet on the instruction leaflets page, and leaflets for older and discontinued products on the earlier leaflets page. Where relevant, check the software version and choose the correct leaflet: the software version is on the side of the dimmer module.

We also have a page of wiring diagrams and how-to videos. Every data sheet links to the product's leaflet: type the product code into the search box. If the wiring diagram is not enough, please contact a qualified electrician.

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Transformers

How should I install VARILIGHT transformers?
  • Always turn off the electricity supply at the mains first. We recommend that transformers are fitted by a qualified electrician.
  • Dimmer switches go on the primary (input) side of the transformer.
  • Install in a well-ventilated place, away from heat sources, and keep at least 30cm between the transformer and the bulb, or another transformer.
  • Do not connect the output cables of one transformer to those of another.
  • Connect bulbs to the transformer in parallel, never in series, and use identical cable lengths on the output side for even light levels.

Full details and distances are in the transformer instructions (PDF).

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Why does my VARILIGHT transformer have more than one set of output terminals?

Although VARILIGHT transformers have a single output, additional sets of terminals are provided on higher-rated transformers so that you can make several terminations to make full use of the rating.

If you have more than two output terminals on your transformer you can use as many pairs as you need. The terminals are paired from the centre outwards: the middle two terminals are a pair, the outer terminals are a pair, and so on.

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Guarantee and older products

The lifetime guarantee, how to claim, and help for products we no longer make.

What does the VARILIGHT guarantee cover?

VARILIGHT products are covered by a lifetime guarantee against faults arising from defective materials or workmanship. "Lifetime" means the expected service life of the product while you own it. The guarantee is for the original purchaser, with proof of purchase.

We will repair or replace faulty units, provided that:

  • the unit has been installed correctly, used only with compatible loads, and not overloaded or run on an incorrect power supply;
  • the dimmer module has not been tampered with (faulty modules from multi-gang units may be removed for servicing without affecting the others).

It does not cover normal wear and tear, accidental damage or misuse, consequential loss or damage, installation costs, or problems caused by incompatibility between lamps and the dimmer. It does not affect your statutory rights.

The lifetime guarantee covers every VARILIGHT product. See our lifetime guarantee.

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Troubleshooting

Dimmers that have stopped working, flicker, buzz or glow, and other problems with installed products.

Flickering, buzzing and glowing

My LED lights flicker: how do I stop it?

Most flicker can be cured with the dimmer's own settings. On V-Pro and V-Com dimmers:

  • Flicker at low brightness: raise the minimum brightness.
  • Flicker at high brightness: lower the maximum brightness.
  • Flashing at any level: change the dimming mode. Mode 1 suits most LEDs; some perform better in Mode 2 or, in some cases, Mode 3.

Also check that:

  • the lamps are described as dimmable, and are all of the same type: our dimmers are not designed for mixed lighting types on one circuit;
  • on a 2-way circuit, only one of the switches has been replaced with a dimmer, to avoid flicker;
  • if your dimmer has a minimum load (the first figure of the rating on most V-Com and V-Dim dimmers), the lamps add up to more than it: see flicker caused by too little load.

V-Pro Multi-Point, V-Pro Multiway and V-Pro Smart dimmers have the same kind of settings: see setting up and programming.

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My dimmer or my lamps are buzzing

It is quite normal for a dimmer switch to buzz a little. A dimmer is more prone to buzz with certain types of lighting load. If your lighting load is causing your dimmer to buzz excessively, we recommend changing the dimmer for a trailing-edge dimmer. Our V-Pro series trailing-edge dimmers are the quietest running dimmers available.

If the LED lamps themselves buzz while a V-Pro dimmer is on, a component within the lamps is vibrating during operation. Changing the driving mode on the dimmer may improve this. If the lamps continue to buzz after trying the different driving modes, we recommend contacting the LED manufacturer for further advice.

With other brands of dimmable electronic transformer, noise levels may vary depending on the type and quantity of transformers used.

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Switches, sockets, USB and transformers

My low voltage lights turn off unexpectedly

If lights on a VARILIGHT transformer turn off unexpectedly, the transformer is most likely overloaded. Reduce the load by using fewer bulbs or bulbs with a lower rating: the total wattage of the bulbs on a transformer must not be more than its rating, or half its rating for a.c. LED lamps (e.g. YT50LZ up to 25W).

VARILIGHT transformers have auto-resetting overload protection (above 200% of the nominal load), auto-resetting over-temperature protection (above 100°C) and short circuit protection. Install them in a well-ventilated place, away from heat sources: see the transformer instructions (PDF).

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Still stuck?

Our customer services team will help. To get the quickest answer, tell us the product code, the batch number from the back of the dimmer, and the make, wattage and number of lamps.