System shut-off is a pressure problem. The automatic shut-off valve isn't activating.
First, check the storage tank valve. It's the blue knob on the tank. Make sure it's open (turned parallel to the tubing).
If the valve is open, the issue is input water pressure. The system needs sufficient pressure to overcome the tank's air charge and to trigger the shut-off valve.
Measure your home's water pressure. If it's below the required minimum, the system will not produce water. The maximum operating pressure is 85 psi. Pressure outside this range causes malfunction.
If pressure is correct, inspect the drain line connection (the drain saddle). A malfunction or improper installation there can cause continuous wastewater flow, preventing the system from pressurizing.
Do not connect the unit to a hot water line. Use cold water only.