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Maintenance

_{Source: Intuition-6 Instruction Manual Rev. H, Page: 102} Regular maintenance ensures accurate measurements and reliable control. The primary maintenance tasks involve sensor cleaning and calibration.

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Maintenance Schedule

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Electrode Cleaning

Use these procedures to restore sensor accuracy and prevent fouling-related drift.

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Contacting Conductivity Electrodes

Graphite Electrodes (Cooling Tower):

1. Remove from process
2. Rinse with clean water
3. Brush gently with soft brush to remove deposits
4. For heavy scaling, soak in dilute acid (10% HCl) for 15 minutes
5. Rinse thoroughly before reinstalling

Stainless Steel Electrodes (Boiler):

1. Remove from process
2. Rinse with clean water
3. For scale, soak in dilute phosphoric acid
4. For oil/grease, clean with mild detergent
5. Rinse and reinstall

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Electrodeless Conductivity Sensors

1. Remove from process
2. Rinse with clean water
3. Use soft cloth to wipe sensing surfaces
4. For stubborn deposits, use appropriate chemical cleaner based on deposit type
5. Rinse thoroughly and reinstall

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pH Electrodes

Routine Cleaning:

1. Remove from process
2. Rinse with clean water
3. Soak in pH electrode cleaning solution for 15 minutes
4. Rinse with clean water
5. Store in pH 4 buffer or KCl storage solution if not reinstalling immediately

For Protein/Oil Deposits:

• Soak in 0.1 M HCl or pepsin solution
• Follow with standard cleaning procedure

For Heavy Scaling:

• Soak in dilute EDTA solution
• Rinse thoroughly

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ORP Electrodes

1. Remove from process
2. Rinse with clean water
3. Clean platinum surface with soft cloth
4. For stubborn deposits, polish with aluminum oxide slurry
5. Rinse and reinstall

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Disinfection Sensors

Membrane-Style Sensors:

1. Remove flow cell from process (close isolation valves)
2. Remove sensor from flow cell
3. Rinse sensing surface with clean water
4. Check membrane for tears or deposits
5. Replace membrane cap if damaged or per schedule

Amperometric Sensors:

• Follow manufacturer-specific cleaning procedures
• May require electrolyte replacement

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Sensor Evaluation

Use these checks to determine whether sensors need cleaning or replacement.

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Evaluating Conductivity Electrodes

Contacting Conductivity:

1. Measure resistance between electrode terminals with multimeter
2. Compare to expected values:
   • 0.01 cell: Higher resistance
   • 10.0 cell: Lower resistance
3. Clean if readings are inconsistent

Electrodeless Conductivity:

1. Check Installation Factor after calibration
2. Should be between 0.5 and 1.5
3. Values outside range indicate coating or positioning issues

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Evaluating pH/ORP Electrodes

pH Electrode Tests:

1. Calibrate with two buffers
2. Check slope value:
   • Good: 54-62 mV/pH
   • Marginal: 48-54 mV/pH (consider replacement)
   • Failed: Below 48 mV/pH (replace)
3. Check response time (should stabilize within 60 seconds)

ORP Electrode Tests:

1. Place in ORP standard solution
2. Compare reading to expected value
3. Check response time
4. Replace if response is slow or reading is significantly off

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Replacing the Powered Relay Fuse

The six powered relays share a common 6.3 A fuse.

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Battery Replacement

The BR2032 lithium coin cell maintains the real-time clock during power outages. Symptoms of Low Battery:

• Date/time resets after power cycle
• Time drifts significantly

Replacement:

1. Disconnect power
2. Open front panel
3. Locate battery on main controller board
4. Remove old battery, note polarity
5. Insert new BR2032 battery
6. Reassemble and power on
7. Set correct date and time

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Calibration Frequency Guidelines

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Preventive Maintenance Checklist

Use these checklists to keep the controller and sensors in good working order.

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Monthly

• Check all sensor readings for reasonableness
• Verify flow through sample lines
• Clean sensors if needed
• Review alarm history
• Check chemical tank levels
• Verify relay operation (put in Hand mode briefly)

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Quarterly

• Calibrate conductivity sensors
• Clean and calibrate pH sensors
• Calibrate ORP sensors
• Verify flow meter calibration
• Check all wiring connections for tightness
• Inspect enclosure seals

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Annually

• Calibrate temperature sensors
• Calibrate 4-20 mA transmitters
• Inspect and test fuse
• Check battery voltage
• Verify all relay operations under load
• Review and update control settings
• Export configuration to USB for backup

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Spare Parts

Keep these items on hand for quick repairs:

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Sources