Your Cube comes with a drain tool that looks like a plastic H and you can find an image in your manual. The transverse end of the tool is used to drain the hub and the hollow end is to drain the pad. Simply place the pad so that the connector is lower than the pad and press the hollow end of the drain cock down into the connector and this will open the valves to release water from the pad. If you want to drain water from the OOLER control unit, unplug the 6-foot tubes from the OOLER control unit.
Take the OOLER control unit to a sink or container, and then insert the drain cock supplied with your OOLER. The water will start to come out.