EDI Module Maintenance and Resin Replacement Guide

Purpose: This guide outlines the steps for basic maintenance of an EDI (Electrodeionization) module, focusing on resin replacement, to restore module performance when a decrease in water quality or increased pressure drop is observed.

Safety First:

• Wear appropriate PPE (safety glasses, gloves, chemical-resistant apron).
• Isolate the EDI module from the system. Follow Lockout/Tagout (LOTO) procedures.
• Release all pressure and drain water from the module before starting.
• Consult the module’s specific manual from the manufacturer.

Part A: Diagnosis & Preparation

1. Symptoms Requiring Resin Replacement:

• Persistent low water quality: Unable to reach >16 MΩ·cm resistivity.
• High pressure drop: Indicates internal blockage.
• Visible resin degradation: Discoloration or broken beads.
• Loss of performance: Confirmed after eliminating other causes.

2. Tools & Materials Required:

• Manufacturer-recommended mixed-bed resin
• Wrenches
• Containers, funnels, tubing
• Rubber mallet
• Lint-free cloths
• Silicone grease
• RO/DI water

Part B: Resin Replacement Procedure

Step 1: Isolation & Draining

1. Shut off power to the EDI stack.
2. Close valves and isolate the module.
3. Drain completely.

Step 2: Disassembly

1. Label all connections.
2. Disconnect piping and electrodes.
3. Unbolt carefully and record component order.
4. Lay components on a clean surface.

Step 3: Resin Removal & Cleaning

1. Remove old resin: Use a container and soft mallet if needed.
2. Inspect & clean:

• Check membranes for damage.
• Rinse with DI water.
• Clean with lint-free cloth.

Step 4: New Resin Loading

1. Prepare resin per manufacturer instructions.
2. Fill chambers carefully.
3. Tap gently to remove air pockets.

Step 5: Reassembly

1. Clean gasket surfaces.
2. Apply silicone grease.
3. Reassemble with correct torque.

Step 6: Startup

1. Reconnect all connections.
2. Flush with RO/DI water.
3. Check for leaks.
4. Power on and monitor.
5. Verify performance.

Important Notes:

• Preventative Maintenance: Regular CIP extends resin life.
• Root Cause Analysis: Identify failure source.
• Professional Service: Contact experts if needed.

Following these steps ensures stable EDI performance and continuous production of high-purity water.