LED globes that glow faintly when off, flicker when dimmed or won't start at a low level. Most of it comes down to the Dimmer Gen4's wiring, calibration and brightness settings.
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Gen4
Start here
What are you seeing?
Pick the closest match and we'll point you to the fix most likely to sort it.
Wired without a neutral, the Dimmer Gen4 needs at least 20 W of globes on the
circuit. Below that, Shelly says it needs a Bypass, and that a Bypass helps
when the lamp glows while it's off.
Flicker is usually the dimmer and the globes not agreeing on the range.
Calibration measures the globes, and the brightness settings keep the dimmer
out of the levels they can't hold.
Before you start
These checks are done in the Shelly app or a browser. Adding a neutral, fitting a Bypass or changing a switch is a job for a licensed electrician. Don't open the wall plate.
Quick checks first
Run these checks before moving on to the fixes.
Checklist0 of 3 checked
Check for a power reading
Open the Dimmer Gen4's web page. Shelly only shows the watts, volts and amps when the dimmer has a neutral, so blank readings mean it's wired without one.
Add up the globes
Add the wattage printed on each globe on the circuit. Under 20 W on a dimmer without neutral is below Shelly's minimum.
Check the globes match
Shelly says every globe on a dimmer should be dimmable and the same model from the same maker.
Fixes, most likely first
Work down the list and stop when it's fixed.
1
Most likely for you
The dimmer has no neutral and too little load
How to tell. The globes glow when off, and the web page shows no watts or volts. Shelly says a Bypass is needed without neutral under 20 W, and can help when the lamp glows while it's off.
Ask an electrician about a Bypass or neutral
A licensed electrician can connect a neutral to the dimmer, or fit a Shelly Bypass for Dimmer at the light. The older Shelly Bypass doesn't suit the Dimmer Gen4.
Recalibrate afterwards
Once the wiring has changed, run the calibration again (the next cause).
Did this fix it?
2
Most likely for you
The dimmer isn't calibrated for these globes
How to tell. The light flickers or steps through the range, and the globes are new, or the dimmer was just reset. Shelly says it must be calibrated after every change of load.
Start the calibration
On its web page, go to Settings, click the light, and next to Calibration click Start. It takes up to 2 minutes; when it works, the light stays on for 10 seconds, then goes off.
Or use the two buttons
Hold both wall buttons for 5 seconds at the same time to start it.
Use a big enough load
Shelly says the globes need to draw at least 3.5 W for the calibration to run.
Did this fix it?
3
Most likely for you
The globes can't run that low
How to tell. It flickers only near the bottom of the range and is steady when turned up. Some LED globes can't run at very low levels.
Raise the minimum brightness
On its web page, go to Settings, click the light, then Min/Max brightness. Raise Min value a little at a time until the flicker stops, and click Save.
Check the level it turns on at
In the light's settings, click Minimum brightness on toggle. It sets the lowest level the light comes on at from a switch, and Shelly's default is 3%.
Did this fix it?
4
Most likely for you
The globes need a boost to start
How to tell. It won't come on, or flickers as it starts, when turned on below 10%. It's fine when turned on brighter.
Turn on Warm up
On its web page, go to Settings, click the light, then Warm up. Tick Enable, set the brightness and time of the boost, then scroll down and click Save.
Update the firmware if it's missing
Warm up arrived in firmware 2.0.0. If the setting isn't there, update the dimmer first.
Did this fix it?
5
Most likely for you
The globes don't suit the dimmer
How to tell. It has flickered since it went in, and calibration stops partway or doesn't help. The packaging doesn't say dimmable, or the globes on the circuit aren't all the same model.
Fit dimmable globes of one model
Replace them with dimmable LED globes, all the same model from the same maker, then run the calibration again.
Leave drivers to an electrician
A downlight with a separate LED driver may need a dimmable driver. Changing it is wiring work for a licensed electrician.
Did this fix it?
6
Most likely for you
The wall switch has a built-in light
How to tell. The switch wired to the Shelly has a locator light or a neon glow in it. Shelly's install guides for the Shelly 1, 1 Mini and 2PM Gen4 say not to use switches with a built-in LED or neon lamp.
Ask an electrician to swap the switch
A plain switch without a light suits the Shelly. Changing it is wiring work for a licensed electrician.
Did this fix it?
On your device
Shelly Dimmer Gen4It's trailing edge only
There's no dimming mode to change
The Dimmer Gen4 dims on the trailing edge and has no leading edge setting, so don't go looking for one. Gamma Correction in its settings smooths how the brightness steps at low levels; it isn't a flicker fix.
