> ## Documentation Index
> Fetch the complete documentation index at: https://docs.supplyline.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Maintenance
> Routine maintenance procedures for Walchem Intuition-6 sensors, electrodes, and controller hardware
# Maintenance
Source: [Intuition-6 Instruction Manual Rev. H](https://supplyline.com/assets/wal/WAL-IOM_Intuition-6-Instruction-Manual-RevH.pdf), Page: 102
Regular maintenance ensures accurate measurements and reliable control. The primary maintenance tasks involve sensor cleaning and calibration.
## Maintenance Schedule
| Task | Frequency | Notes |
| ----------------------------------- | ----------------- | ------------------------------- |
| Sensor cleaning | Weekly to monthly | Depends on water quality |
| pH/ORP calibration | Monthly | Or when readings drift |
| Conductivity calibration | Quarterly | Or when readings drift |
| Disinfection sensor calibration | Weekly | Process calibration recommended |
| Membrane replacement (disinfection) | 3-6 months | Per sensor manual |
| Visual inspection | Monthly | Check for leaks, damage |
| Fuse inspection | Annually | Replace if discolored |
| Battery replacement | 5-7 years | Real-time clock backup |
## Electrode Cleaning
Use these procedures to restore sensor accuracy and prevent fouling-related drift.
### 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
Never use abrasive materials on electrode surfaces. Scratches affect calibration and accuracy.
### 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
### 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
Never wipe pH glass bulb with dry cloth—this generates static charge that affects readings. Always rinse with water.
### 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
### 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
## Sensor Evaluation
Use these checks to determine whether sensors need cleaning or replacement.
### 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
### 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
## Replacing the Powered Relay Fuse
The six powered relays share a common 6.3 A fuse.
Disconnect power before opening the controller enclosure.
Turn off the power switch AND disconnect power at the source.
Remove the four screws and carefully open the front panel.
The fuse is located on the power/relay board.
Gently pull the fuse from its holder.
A blown fuse will have a broken wire or discolored glass.
Insert replacement fuse: 6.3 A, 5 x 20 mm, 250V fast-acting.
Close front panel, reinstall screws, reconnect power.
If the fuse blows repeatedly, check for short circuits in connected equipment. Total relay load must not exceed 6 A.
## 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
## Calibration Frequency Guidelines
| Sensor Type | Typical Frequency | Increase If... |
| -------------------------- | ---------------------- | -------------------------------------- |
| Contacting Conductivity | Quarterly | Heavy scaling, coating |
| Electrodeless Conductivity | Quarterly | Coating, temperature swings |
| pH | Monthly | Aggressive chemistry, high temperature |
| ORP | Monthly | Low residual applications |
| Free Chlorine | Weekly | Varying water quality |
| Total Chlorine | Weekly | High organic load |
| Temperature | Annually | Critical applications |
| 4-20 mA Transmitters | Per transmitter manual | Drift observed |
## Preventive Maintenance Checklist
Use these checklists to keep the controller and sensors in good working order.
### 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)
### 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
### 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
## Spare Parts
Keep these items on hand for quick repairs:
| Part | Purpose |
| ------------------------------------ | --------------------------------- |
| Replacement sensors | Minimize downtime during failures |
| pH buffer solutions (4, 7, 10) | Regular calibration |
| Conductivity standards | Calibration verification |
| Flow cell o-rings | Seal replacement during cleaning |
| Membrane caps (disinfection sensors) | Scheduled replacement |
| Fuses (6.3 A) | Relay fuse replacement |
| BR2032 battery | RTC backup |
## Sources
Page 102 • February 2024