Brand: ABB
Category: Other
Document Type: Manual
Language: EN
Manual for AP300
Uploaded: April 20, 2026, 8:04 p.m.
Manual Publish Date: 2018-01-01
Warranty Information
None
The AP300 Series Industrial pH and Redox (ORP) Electrode Systems are designed for reliable and cost-effective measurement in various industrial applications. The manual covers installation, calibration, and maintenance of three main sensor types: AP301 (twist-lock), AP302/3 (screw-in), and AP304/5 (ball valve hot-tap). It details sensor descriptions, mechanical and electrical connections, calibration procedures for both pH and Redox sensors, and troubleshooting common issues. Maintenance instructions include general cleaning methods for different deposit types and proper storage of the electrode to prevent damage. Spares and accessories are also listed.
Troubleshooting and error codes
| Symptom | Possible Cause | Solution |
|---|---|---|
| Short scaling (Low Slope) or sluggish response | ||
| Glass sensor membrane dirty or coated | Refer to Section 5.1 for cleaning. | |
| Poor insulation on cable connectors, possibly due to moisture | Dry connectors with warm air. | |
| Replace the sensor if no improvement is seen. It may also be necessary to replace the extension cable if used. | ||
| No response to pH buffer or sample | ||
| Sensor not correctly wired | Check the sensor has been correctly wired to the transmitter as detailed in Section 3.1, page 12 and the relevant transmitter instruction manual. | |
| Check the glass sensor membrane is not broken or cracked. | ||
| Unstable readings or drift | ||
| Sensor not correctly wired | Check the sensor has been correctly wired to the transmitter as detailed in Section 3.1, page 12 and the relevant transmitter instruction manual. | |
| Dry or dirty reference junction | Clean the junction as detailed in Section 5.1. | |
| Replace the sensor if no improvement. | ||
| Stable but incorrect readings | ||
| Recalibrate | Using fresh buffer solutions. | |
| Check temperature compensation settings | Correct manual temperature or automatic temperature compensation is reading correctly. | |
| Offset of <1.0 pH to >0.2 pH | Perform a one-point process calibration (see Section 4.1, page 14). | |
| Note: All the above symptoms could be caused by a faulty extension cable. Check and replace it, if necessary. | ||