Q&A for Frequently Asked Questions regarding PAK’s Dimmable LED Downlights

Author: Steve Law (Technical & Sales Support)

Editor: Neil Chen



This article is applicable only for our C101, X108 and C103 series LED downlights. However, if you are instead having difficulties with Clipsal®’s products, PAK strongly recommend that you consult with Clipsal’s technical support team before taking any further actions. PAK is not responsible for any damages or loss that’s caused by incorrectly using products of other brands.

Q&A for frequently asked questions

1.    What dimmer should I use for my PAK LED downlights?

A: Our dimmable LED driver is designed mainly for Trailing edge and Universal dimmers. However, you may find that they will also work on some digital dimmers. We recommend that you consult with one of PAK’s Technical staffs before proceeding.

To find out more about the working principles of different dimmers, please refer to the following article for more information:

How to Choose a Dimmable LED?

2.    What will happen if I have used an incorrect dimmer for my PAK downlight?

A: Before answering this question, we strongly recommend that clients consult our technical staffs, as they need to ascertain if the dimmer is suitable for PAK downlights.

As a guide, two consequences are likely for general dimmable downlights on the market which have been fitted with non-compatible dinners:

1. The light cannot be dimmed at all

This normally happens if the dimming protocol of the dimmer does not match the circuit design of the driver. For instance, you use ananalogue 1-10V dimmer to dim a LED light with Phase-cut (or TRIAC) dimmable driver, or vice versa, your light will not respond to the dimmer.

2. The light can be dimmed, but you hear buzzing noise when it’s dimmed to low output levels

This normally happens when the dimmer has the same protocol as the driver circuit design, but the methodology is different. A common case of example is that when a Trailing edge dimmable downlight is dimmed by a leading edge dimmer, it will normally has noticeable buzzing sounds from the driver, when it is been dimmed to 20%~30%.

3.      Why is my PAK downlight flickering, even if I have used the correct dimmer?

A: This can be as a result of two reasons:

1) Mismatch of frequency or voltage of Input AC current from regional grid system with the LED driver

This is caused by the variation of the AC voltage from the Grid system. Although it is commonly known that the standard AC voltage in Australia is 220-240V, in fact, in some regions, the voltage can sometimes go up to more than 250V.

Because of this kind of variation, the LED driver cannot have a consistent waveform of input current. Therefore, the output direct current will also be unstable, which will lead the LED chips to be on-and-off in a frequency that is insufficiently high to be invisible. That is why we can see the light flickering.

The solution for this problem is to install a Load Correction Device (LCD) in parallel to the dimmer. This electrical element will balance the input voltage to the dimmer, which may be able to stop flickering from happening again. The most typical LCD in the market is the Clipsal® 31LCDA, however, according to Clipsal®’s Technical Support team, this device is not guaranteed to solve the problem 100%.

2) Off-peak ripple

Similar to the phenomenon that is described above, Off-peak ripple is the AC frequency variation due to the change of supply load, during the intersection between on-peak and off-peak supply.  As a result, electrical appliances with high load (e.g. hot water system) will produce a certain level of magnetic field, which infects with the operation of LED drivers, and cause the LED downlight to flicker.

This problem is yet to have a guaranteed solution, however, there are some suggestions that are worthy of trying. Firstly, the load correction device may be able to correct the input load. Secondly, some digital dimmers claim to have the ability to withstand off-peak ripples. However, as we haven’t tested them before, I suggest that clients should carefully consult the supplier before they use a dimmer.

For more information about the flicking of LED downlight, please check the article below:

LED Flickering: A Devil hides under the Light

4.      Why my PAK Downlight does not work when connected to my C-bus system ?

A: There are three possible reasons for this problem:

1) There are no dimmer(s) in the C-bus network,

2) The dimmer in the C-bus network is not compatible with the LED downlight

3) The dimmer is not working properly

The way to clarify if it is caused by reason 1 or 2 is to plug in a laptop to the computer interface, and check the network status with the C-bus toolkit software. Through the software, you can see a list of all the components of the network, and their working status. Please be careful that PAK’s downlights only work for the C-bus Universal dimmers. To figure out if your dimmer is the correct one, please check the following article:

Brief explanation of Clipsal C-bus system and its compatibility with dimmable LED lights

If the cause of the problem still cannot be found, you can connect a halogen light to the circuit, and try to dim it with the C-bus system. If the light cannot be dimmed, then it is sure that the dimmer is not working properly. In this case, I suggest our clients to contact the Clipsal technical support team for a proper trouble shooting.

If you have any other questions regarding to the PAK LED downlights, please send us an email to: info@paklighting.com.au