Dimmer switch not turning on light until at 50%?

Question

I recently had a professional electrician install a ceiling fan with a light fixture. The fan and light are controlled from a combo switch with two knobs - one is a dimmer switch for the light, and one is a three-speed fan control.

What I have observed is that if the dimmer switch is completely off, when I go to turn it on, the light does not turn on until the dimmer switch reaches about 50%. Once the light comes on, I can turn the dimmer switch down below 50%, and the light will dim as expected.

In a previous house I lived in, I had a ceiling fan light fixture controlled by a dimmer switch that did not have this problem. So I'm curious what might be different in the new setup that is causing this behavior?

I'm using the bulbs that came with the fan, and they are incandescent, so there shouldn't be any problem with the bulbs, as far as I know...

Answer 1

Many dimmers have an adjustment for the minimum level. You don't mention what type of dimmer you have but you can consult the instructions on how to adjust this. As @dslake mentions in his answer, adjustments might be via a knob or screw, but if it's digital, it could also be a button sequence.

Needing to perform this is more common with electronic dimmer switches since they need to work for many different types of bulbs (incandescent, CFL, LED).

Answer 2

Most dimmers have a little screw behind the face plate that should be adjusted to set the minimum power level that will be delivered to the bulb. Here are some generic instructions that worked for the dimmers I've installed recently:

Dimming Range Adjustment

1. Turn dimmer on and move slider down to the bottom.

2. Turn adjustment dial up or down until lowest desired light level is achieved and light output is stable for all bulbs.

3. Turn dimmer off, then back on to verify that all bulbs turn on.

4. If all bulbs do not turn on, turn adjustment dial to increase power slightly and repeat step 3.

5. Once all bulbs are dimming properly, install faceplate.

Troubleshooting

Symptom:

• Bulbs turn off while being dimmed.
• Bulbs turn on at high light level but do not turn on at a low light level.
• Bulbs flicker or flash when dimmed to a low light level.

Solution - Follow the steps below:

• Remove faceplate and locate adjustment dial.
• Turn adjustment dial down (counter-clockwise) slowly until symptom is no longer present. Assumes counter-clockwise is brighter.
• Install faceplate once all bulbs are dimming properly

Source: Lutron: Dimming Range Adjustment