When you see a low water level or a "#900 Cooler Off" dialog appears on the touchscreen. Please add water to the water tank.
1. Unplug the machine.
2. Remove the back lid by unscrewing the 6-star screws with the hex key in the Accessory Kit.
3. Open the water tank with the small wrench.
4. Fill up the tank using distilled water. Watch the water level carefully to prevent from spilling over. Seal the tank when the water level reaches 80% full.
It is recommended that the water should be changed once every 3 months.
- Repeat Step 1 and 2 of "Adding Water".
- Remove the hose clamp with pliers and pull apart the hose from the white connector of the flow sensor. Place the two ends of the hose into a container to prevent water from spilling out.
- Remove the laser head, plug the air outlet into the water pipe. Go to touchscreen and press Action > Air Pump, the water will be blown out from the other end. Press "Air Pump" again when water is drained from the water tank and hose.
- Repeat Step 3 and 4 of "Adding Water."
- Restart the machine. Go to touchscreen and press Action > Air Pump. The water in the tank will be pushed into the cooling system. Repeat Step 4 until the water level no longer decreases.
Excessive bubbles in the laser tube may decrease the cooling efficiency. It is recommended to fill the water tank more than 80% to decrease bubble generation.
Here is another video tutorial for water cooler Maintenance.
Thanks for Mr. Dav Glass' Sharing.