Electrochemical chlorine sensor AS3

for water treatmentdigitalanalog

Product Summary
German-made amperometric residual chlorine sensor AS3 for precise monitoring of free chlorine in drinking and hot water up to 70 °C. The sensor operates with a potentiostatic three-electrode system and provides stable, accurate signals for disinfection control. Outputs include analog (voltage / 4-20 mA), digitally processed analog and Modbus RTU. Integrated automatic temperature compensation (0-70 °C) and a PEEK body support use in elevated-temperature or demanding water-treatment environments. Optional RV1 automatic electrode cleaning reduces manual maintenance.

Special features

• Suitable for high water temperatures
• Suitable for high pressures
• Short response time
• Tolerates surfactants
• Reduced maintenance with optional RV1 automatic electrode cleaning

Applications

• Drinking water
• Hot water applications

Ambient conditions

• Stable pH value (attention to HOCl dissociation equilibrium)
• Max. measuring water temperature: 70 °C (no ice crystals in the measuring water)
• Ambient temperature: 0 ... +55 °C
• Max. allowed working pressure: up to 8 bar (operation with retaining ring in FLC; avoid pressure surges/impulses and vibrations)

Technical Specification (table)
Measurement parameter: Free chlorine
Measuring ranges / resolution: 0.005…2.000 ppm: 0.001 ppm; 0.03…20.00 ppm: 0.01 ppm; 0.5…200.0 ppm: 0.1 ppm; 0.003…1.000 ppm: 0.001 ppm; 0.003…2.000 ppm: 0.001 ppm; 0.03…5.00 ppm: 0.01 ppm; 0.03…10.00 ppm: 0.01 ppm
Response time: T90 ≈ 30 seconds
Measuring water temperature: 0 ... +70 °C (no ice crystals in the measuring water)
Ambient temperature: 0 ... +55 °C
Temperature compensation: Automatic by integrated temperature sensor; response time ≈ 10 min; max. change in temperature: 30 °C per hour; avoid sudden temperature changes
Max. allowed working pressure: Operation with retaining ring in FLC: -0.5 bar (no pressure impulses/vibrations) and up to 8 bar (no pressure surges/vibrations)
Flow rate (face velocity): Without RV1: min. 15 l/h; With RV1: 45-90 l/h
pH range: pH 5 – pH 9 (attention to HOCl dissociation equilibrium)
Run-in time: First start-up approx. 1 h up to 2 days, depending on water quality
Zero point adjustment: Not necessary
Protection class: 5-pole M12 plug-on flange: IP68; 2-pole terminal with mA-hood: IP65
Material: PEEK

Technical characteristics

• Model: AS3
• Measurement parameter: Free chlorine
• Measuring ranges / resolution: see detailed ranges above (from 0.003 ppm up to 200.0 ppm depending on range)
• Response time: T90 ≈ 30 seconds
• Measuring water temperature range: 0 ... +70 °C
• Ambient temperature range: 0 ... +55 °C
• Maximum allowed pressure: up to 8 bar (with conditions; avoid pressure surges/vibrations)
• Temperature compensation: Integrated automatic temperature sensor
• Protection: IP68 (M12 plug) / IP65 (2-pole terminal with mA-hood)
• Body material: PEEK