RO Pump – Troubleshoot Guide- No Shut-Off

Byadmin6688

　　RO Pump – Troubleshooting Guide: Persistent Flow Problem

　　If your RO system is continuously expelling wastewater without interruption, even when the storage tank is full, there are three essential valves that play a role in the shut-off mechanism. Consult the diagram to identify these valves:

  1. Electric Shut Off (ESO) valve: This is responsible for halting the pump when the tank is full.
  2. Tank Shut Off (TSO) valve: This prevents water from entering the tank once it reaches full capacity.
  3. Check Valve (Point E): This helps in building tank pressure (up to 40psi), indicating the TSO to stop intake. Subsequently, the ESO also ceases the pump operation.

　　A malfunction in any of these valves can result in continuous pump operation and wastewater discharge. To troubleshoot, conduct the following tests:

  1. 　　RO Shut-Off Function Test:

    • As the RO system produces water, the pump runs and wastewater is drained.
    • Close the tank valve to mimic a "full tank" situation.
    • If the RO stops producing water, and the pump and wastewater cease flowing, the system is shutting off correctly.
    • If the pump and wastewater continue to flow, the RO is not shutting off properly. Further testing of the Check Valve and TSO/ESO valves is necessary.

  2. 　　Check Valve & TSO/ESO Valves Test:

    • Let the RO fill the tank.
    • Turn off the cold water supply to the RO.
    • Open the tank valve.
    • Disconnect the RO’s black drain line from the drain pipe and check for any water flow.
    • If water flows from the line, the Check Valve is defective and needs replacement.
    • If no water flows, the Check Valve is functioning correctly, and the issue is with the TSO and/or ESO valves, which require replacement.

  3. 　　Inspect Additional Output Points:

    • If the RO provides water to multiple outlets (icemaker, coffee maker, etc.), ensure all output lines and T-fittings are free of leaks. Any leaks can prevent pressure buildup, causing the RO to fail to shut off.

　　—– End of Test —–

　　Note: Prolonged failure to shut off can deplete the 1st, 2nd, and 3rd stage pre-filters. If the RO does not shut off for 3-4 weeks, replace these pre-filters to protect the membrane. Test the membrane’s condition with a TDS meter if available.

　　Reminder: Annual pre-filter replacement is essential. Timely replacement prevents damage to the stage-4 membrane and shut-off valves.

　　Water flow through the RO head is as follows:

  • A: Input water enters the stage-1 sediment filter at point A.
  • ESO: Water then proceeds to the Electric Shut Off (ESO) valve.
  • P1: From ESO, it enters the booster pump at port P1.
  • P2: Boosted water exits the pump at P2 and heads to the stage-2 filter.
  • B: Water exits the stage-3 filter at port B.
  • D: From B, it enters the Membrane housing at point D.
  • W: Waste water exits through point W.
  • E: Purified water exits the membrane at point E.
  • Check Valve: Located at point E, it prevents backflow into the RO system and aids in shut-off when the tank is full.
  • T1, T2: Pure water enters the TSO Tank Shut Off valve at T1 and exits at T2.
  • TSO: The TSO valve stops the tank intake at 40psi.
  • F, G: Pure water moves through points F & G to the pressure tank.
  • H: Dispensed water exits the tank via the Yellow line, through the Stage-5 filter at point H, and to the RO faucet.

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