When to Change RO Purifier Filters (TDS Levels & Solenoid Valves)

The Stages of Water Purification

An RO (Reverse Osmosis) water purifier cleans water through a multi-stage process: Pre-Filter, Sediment Filter, Pre-Carbon Filter, RO Membrane, UV Chamber, and Post-Carbon Filter. Over time, these filters trap organic matter, chlorine, and salts, losing efficiency.

Key Indicators That Filters Need Replacement

• Drop in Water Flow: If it takes 2 hours instead of 30 minutes to fill your storage tank, the pre-filter or membrane is choked.
• Increase in TDS (Total Dissolved Solids): Test your purified water with a TDS meter. If input water is 500 PPM and output exceeds 80 PPM, the RO membrane is degraded and allowing minerals to pass.
• Continuous Reject Water Flow: A failing Solenoid Valve (SV) will fail to shut off the supply, letting raw water drain constantly.

Why the Booster Pump is Crucial

The RO membrane has microscopic pores and requires high water pressure (~60-80 PSI) to force water molecules through. The booster pump provides this pressure. If the pump is weak, the reject water ratio will increase, and the purified water tank will never fill.