Fault Diagnosis Characteristics of Conductivity Electrode 2401B-0.01

Fault Diagnosis Characteristics of Conductivity Electrode 2401B-0.01

• The conductivity reading drifts more than 0.1 μS/cm per hour, or deviates from manual sampling results by >5%.

• After unit make-up water, the reading shows no significant change, or suddenly rises/falls and fails to stabilize.

• Drift reappears within a short time (<24 hours) after cleaning the electrode.

• Abnormal temperature compensation, with deviation >2°C from actual cooling water temperature.

II. Step-by-Step Troubleshooting Procedure (Based on Power Plant Chemical Operation Standards)

1. Sampling Comparison (15 minutes)

• Collect a stator cooling water sample and measure with a calibrated portable precision conductivity meter in the laboratory. Compare with the online electrode reading to determine if the fault originates from the electrode.

• Measure the water sample’s pH (normal range 7.5–8.5) and turbidity (≤0.1 NTU) to confirm whether abnormal water quality is causing electrode contamination.

2. Electrode Body Inspection (30 minutes)

• Close the measuring circuit valve, remove the electrode, and inspect the platinum ring surface for:

  • White scale (calcium/magnesium salts)

  • Brown rust (iron oxides)

  • Black slime (microorganisms)

• Check the electrode sheath for damage, air bubbles trapped in the cavity, or reference solution leakage (Note: 2401B-0.01 is a four-electrode type with no reference solution; focus on the connection between the platinum ring and the lead wire).

3. Temperature Compensation Check (20 minutes)

• Measure the resistance of the built-in PT1000 temperature sensor with a multimeter and compare it to the PT1000 temperature-resistance table to verify temperature accuracy.

• Confirm the transmitter’s temperature compensation mode (auto/manual) and that the automatic compensation parameter is correct (temperature compensation coefficient for stator cooling water is 0.02/°C).

4. Transmitter and Loop Inspection (25 minutes)

• Connect the electrode to a standard conductivity signal source to check transmitter output and rule out transmitter failure.

• Inspect the measuring circuit cable for leakage, short circuits, and proper grounding to avoid ground loop interference.

III. Core Treatment Methods for Conductivity Electrode 2401B-0.01 (Targeted by Contamination Type)

A. Deep Cleaning of Platinum Ring (Critical Step)

• Scale contamination (white salt scale): Prepare 5% dilute hydrochloric acid (analytical grade). Soak the platinum ring for 10–15 minutes, gently scrub with a soft nylon brush, rinse with tertiary reverse osmosis (RO) water three times, then soak in stator cooling water sample for 5 minutes to reactivate.

• Oxidation contamination (brown rust): Prepare 10% dilute sulfuric acid, soak for 5–8 minutes, rinse, then wipe the platinum ring with anhydrous ethanol to remove residual oxides.

• Microbial contamination (black slime): Prepare 2% sodium hypochlorite solution, soak for 15 minutes to kill microorganisms, then rinse repeatedly with pure water to avoid disinfectant residue affecting measurement.

⚠️ Do not use sandpaper, steel wool, or hard objects to scrub the platinum ring – this will damage the electrode coating and cause permanent drift of the cell constant.

B. Air Bubble Removal and Installation Optimization

• Remove the electrode sheath, expel any trapped air bubbles from the cavity, and reinstall ensuring the platinum ring is fully immersed and located in flowing cooling water (avoid dead zones). Add an anti-bubble baffle if needed.

• If the cooling water flow velocity is too low (<0.5 m/s), coordinate with operations to adjust flow rate, ensuring fresh water sample is constantly present at the electrode surface.

C. Electrode Constant Calibration (When Drift Exceeds Limit)

• Prepare two standard conductivity solutions (e.g., 10 μS/cm and 100 μS/cm) suitable for low-conductivity stator cooling water conditions.

• Immerse the electrode in each standard solution at 25°C constant temperature, and use the transmitter’s built-in calibration function to adjust the cell constant to the standard value (rated cell constant for 2401B-0.01 is 0.01 cm⁻¹).

• If the deviation remains >±2% after calibration, the electrode is considered damaged and should be replaced with the same model. After replacement, perform three parallel sample tests to ensure measurement error ≤3%.

IV. Preventive Measures and Emergency Plan for Electrode 2401B-0.01

Preventive Measures

• Weekly: Simple cleaning by rinsing with pure water.

• Monthly: Deep cleaning based on water quality.

• Quarterly: Calibrate the cell constant with standard solutions.

• Add a slow-release agent to the cooling water system to reduce scaling and microbial growth.

Emergency Plan

• If measurement drift severely affects water quality control, immediately switch to manual sampling testing (once every 2 hours) and adjust chemical dosing and make-up water based on results.

• Replace with a backup electrode to restore online monitoring.

DFYLSYC-2026-06-15-A