1. Scope of application
This manual establishes maintenance procedures for cooling systems, including biocide dosing, corrosion sample analysis, and purging management. Adherence to these guidelines is critical to preventing scaling, corrosion, and microbiological contamination in closed and open cooling systems.
2. Safety measures
WARNING: Working with chemical reagents is dangerous. Use personal protective equipment (PPE): chemically resistant gloves (nitrile), safety glasses, an apron and special shoes. Read the Material Safety Data Sheets (SDS) for all biocides and inhibitors before starting work.
DANGER: Perform a Lockout/Tagout procedure before servicing dosing pumps, purge valves, or when handling corrosive samples under pressure. Depressurize the system to zero before disconnecting any lines.
3. Tools and materials
| Name of the tool | Specification | Quantity |
|---|
| Gas wrench / Socket wrench | Up to 300 mm | 2 |
| Torque wrench | 5-30 Nm | 1 |
| Portable photometer | For Cl, Br, P analysis | 1 |
| Conductometer | 0-10000 μS/cm | 1 |
| Kit for cleaning coupons | Brush, cleaner | 1 |
4. Pre-technical inspection
| Element | Verification | Criteria (Accept/Reject) | Notes |
|---|
| Dosing pumps | Leakage, oil level | No leaks / Normal level | Check the tightness of the hoses |
| Purge valve | Working condition | Full opening/closing | Check the response time |
| Reagent container | Level | Level > 20% | Top up if necessary |
5. Step-by-step procedure
5.1 Dosage of biocides
- Check the level of concentration of microorganisms in the water (test strips or ATP test).
- Adjust the frequency of strokes of the dosing pump in accordance with the technical regulations (typically 50-80 strokes/min).
- Error: Do not check biocide compatibility with other reagents.
- Open the shut-off valve on the injection line.
5.2 Analysis of corrosion samples (coupons)
- Close the isolation valves on the bypass of the corrosion rack.
- Release the pressure gradually (maximum 0.5 bar before opening).
- Remove the sample, clean it according to ISO 8044, weigh to the nearest 0.1 mg.
- Install a new sample, tighten the fasteners with a torque of 15-20 Nm.
- Error: Tightening fasteners without a torque wrench.
5.3 Optimization of purging
- Measure the electrical conductivity of the water in the system.
- Set the limit value according to the pipe materials (eg 1500-2000 µS/cm for carbon steel).
- Adjust the purge valve to automatically maintain the set conductivity.
6. Inspection after maintenance
| Test | Expected result | Actual result | Status |
|---|
| Sealing of connections | No drops | - | - |
| Feed reagent | Steady flow | - | - |
| Conductivity | Within setpoint | - | - |
7. Troubleshooting
| Symptom | Probable cause | action |
|---|
| High corrosion | Low inhibitor concentration | Increase dosage, check P level |
| Biological plaque | Ineffective biocide | Change the type of biocide (alternative) |
| Scum | High concentration of salts | Increase the intensity of purging |
8. Maintenance schedule
| The task | Frequency | time | Skill level |
|---|
| Measurement of conductivity | Every day | 10 min | Operator |
| Dosage of biocides | According to the schedule | 30 min | Technician |
| Analysis of coupons | Every month | 1 hour | Engineer |
9. Spare parts
| Description | Specification | UNITEC-D category |
|---|
| Dosing pump | Membrane, 10 l/h | Dosing systems |
| Purge valve | Solenoid, 1/2'' | Armature |
| Corrosion samples | Carbon steel / Copper | Measuring equipment |
Order the required components at https://www.unitecd.com/e-catalog/
10. Links
- ISO 8044: Corrosion of metals and alloys.
- Water quality standards for industrial purposes.
