I bought some dimmable LED’s from you but they don’t appear to be working correctly, is it my dimmer?

Customer Question 

I bought some dimmable LED’s from you but they don’t appear to be working correctly, is it my dimmer?


Technical Tim
One thing I should stress as we discussed is that non-dimmable LEDs must NEVER be used in a dimmer circuit even if the “dimmer function” is not used and the dimmer control is turned to full; it is not the same as having a simple on/off switch. Not only will the LEDs not dim as expected they will not perform correctly with the modified electrical supply from the dimmer even at full output. The simple result will be failure of the LEDs, dimmer unit or both. As you commented you have heard a noise from the dimmer, this is indicative of imminent trouble.

The most probable reason the current dimmers that you have work erratically with the dimmable LED devices I understand you have is due to the minimum loading requirement of the existing dimmer units which are intended for incandescent/halogen lamps.

The dimmer units will have a MINIMUM load requirement of around 30w although this will vary from individual unit to individual unit. If the load on the dimmer is less than the minimum requirement than it is more than likely the dimmer will not perform as required and as expected, typically the LED unit will flicker, will not dim at all or will only have a limited range of dimming. As you have a number of dimmers I would not expect them all to perform identically due to tolerances between individual dimmers and the total load presented by the LED lamps which will also vary due to individual differences.

Now if I understand correctly from our conversation, you have a particular unusual arrangement with regards the loading you have on your dimmers in so much as you only have 2 LEDs per dimmer circuit which presents a theoretical load of 14w which is far below the minimum load of a traditional incandescent dimmer unit. The results of using a low load with a dimmer will be variable to say the least.

We have actually set up a special test circuit to confirm our previous findings and we can confirm that a specified dimmer will work correctly and dim from full off to full on with a low load as you require for the 2 LED units; even LED dimmers have a minimum load requirement and your requirement of 2 LEDs per dimmer is close to this value especially taking product tolerances into account.

For the dimmable LED lamps you have you will require dimmers from the V-Pro Professional Universal Series which have a Prefix code J.

You mentioned that you have 4 dimmers on the one white (twin) panel so a 4 way dimmer unit in white would be JQDP254 on page 6.

If you require the panel so that there are no screws visible you would require JDQDP254S on page 16.

Your requirement also for a 4 way panel with 2 simple on/off switches and 2 dimmer units probably poses a problem at the moment though and it may be better to go for the simple option of duplicating the 4 dimmer panel above and using dimmable LEDs; non-dimmable LED’s will not work.

These dimmer units have a programmable feature, explained in the fitting instructions which permits them to be set for varying lamp numbers in order to achieve the full and correct dimming range from full off to full on.

I hope the information is of some use to you. If you require any further information or assistance please do not hesitate to contact me.

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