This happens sometimes. There's nothing wrong with the generator. If the water is extremely pure, the generator won't pull up to the set current at first and will [sorta] run away till it reaches the set current control point. The LED will be very dim and gradually brighten to normal.

Since 'runaway' progresses very slow at first, then faster and faster...it can take literally hours just to get things started. The only electrical way out of that is to raise the initial voltage...but..no DC componants are available that will handle more than the voltage I'm already using.

The other way out of that is to increase the initial conductivity of the water by adding some of a previous batch of colloidal silver. If this is the first batch...don't worry, just wait.