Diagnosis: The storage tank is not filling. Primary causes are insufficient water pressure or an installation error.
- Verify the tank shut-off valve is open (valve handle in line with the yellow tubing).
- Check all tubing connections per the installation diagram (points A-B, C-D, E-F, G-H).
- Inspect for kinked tubing blocking flow.
- Measure incoming water pressure. Minimum required is 45 PSI. Below this, the RO membrane cannot function and the tank will not fill. Operating range is 45-70 PSI.
- If pressure is below 45 PSI, a booster pump is required.
If pressure is adequate and connections are correct, allow the system 1.5 to 2.5 hours to fill the tank from empty. Fill time depends on water temperature (40–100 °F), TDS (up to 750 ppm), and pressure.