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Residual Chlorine Dioxide Monitor Model Q46H/62-63

For pricing, please call AFC International at 1-800-952-3293, 219-987-6825 or fax 219-987-6826 or email



The Model Q46H/62-63 Residual Chlorine Dioxide Monitor system uses a polargraphic membraned sensor to measure chlorine directly, without the need for chemical reagents. When needed, automatic pH compensation may be added for highest free chlorine measurement accuracy and systems are available to provide 4-20mA outputs for chlorine, pH, and temperature to allow easy CT calculations.

Q46H systems are economical to purchase, economical to maintain, and provide long term accuracy and reliability for your chlorine monitoring needs. Monitor capabilities have been expanded to include options for a 3rd analog output or for adding additional low power relay outputs. Digital communication options for Profibus, Modbus or Ethernet have also been added.

Two types of chlorine sensors are available, one designed for flowcell installation and one for submersion applications. Free chlorine monitoring should always be done using a flowcell system. Good control of sample flow and pressure is important for accurate measurement, and the standard constant-head flowcell should be used for most applications. A sealed flowcell and a low-volume flowcell are also available for special applications.

Submersible combined chlorine sensors can sometimes be used for measuring total chlorine in wastewater effluent. Wastewater effluents containing more than 1 ppm of ammonia often result in a chlorine residual that is more than 90% microchloramine. Direct measurement with a submersible sensor can provide a dependable monitor without all the sampling and chemicals associated with total chlorine measurement.

Chlorine sensors, especially free chlorine, require up to 8 hours of stabilization time when first installed or after membrane change. The Q46H offers a battery powered “polarizer” that can be used to stabilize a spare sensor so it is ready to run within a few minutes of installation. Polarizers simply plug into the sensor connector and require no adjustments.

Standard Q46H systems are AC powered 9100-240 VAC, 50/60 Hz) but a 12-30 VDC version is also available. The basic system includes 2 isolated 4-20 mA outputs and 3 SPDT alarm relays. If pH correction is required, or if pH measurement is also desired, an optional pH sensor is available. With this sensor connected, the second analog output may be configured for pH instead of temperature to provide a dual chlorine/pH monitor system. Q46H systems may also be supplied with an additional output board. this output board may contain either a third 4-20 mA output or three additional low power relays. Adding the third analog output is the most common as the system then provides isolated outputs for chlorine, pH and temperature. In addition to the analog output options, Q46H monitors may be supplied with digital communications. A Profibus-DP interface is currently available, with Modbus and Ethernet options under development.

For pricing, please call AFC International at 1-800-952-3293, 219-987-6825 or fax 219-987-6826 or email


  • Offers Free or Combined Chlorine measurement
  • Economical Operation
  • Automatic pH Compensation
  • Dual Chlorine/pH Monitoring
  • Programmable range options from 0-200 PPB up to 0-200 PPM provide maximum application flexibility
  • AC or DC Power Options
  • Two isolated 4-20 mA outputs are standard, with an option for a third output if required. Default setting provides analog outputs for chlorine and pH
  • Standard PID control function assignable to one analog output
  • Available in either Profibus-DP, Modbus-RTU or Ethernet-IP
  • Three SPDT relays are standard, with relay functions programmable for alarm, control, or trouble indication. Three additional low power relays available as an option
  • NEMA 4X (IP-66) enclosure is suitable for wall, pipe, or panel mounting
  • Back-lit large LCD display provides clear visibility in any lighting conditions. A scrolling second line on the display provides additional information and programming prompts


Display Range 0-2.000 ppm, 0-20.00 ppm, or 0-200.0 ppm
Accuracy ±0.01 ppm
Repeatability ±0.01 ppm
Linearity 0.1% of full scale
Zero Drift < 0.01 ppm per month
Display 4 digit main display, 0.75″ characters, 12 digit alpha numeric second line display
Power 100-240 VAC ±10%, 50/60 Hz, 10 VA Max 12-24 VDC, 50 mA Max Optional
Analog Outputs Two isolated 4-20 mA, 500 ohm max standard
Relay Mode Three SPDT, 6A @ 250 VAC standard
Three additional SPST low voltage relays optional
Operating Temperature 0 to 50°C
Enclosure NEMA 4X (IP-66) polycarbonate wall, panel or pipe mount
Weight 6 pounds

Sensor Specifications

Sensor Membrane covered polarographic sensor
Optional pH Sensor Combination pH sensor with or without preamplifer
Materials PVC and 316 stainless steel
Sensor Cable 25′ standard, 100′ maximum
Response Time 90% in 60 seconds
Temperature Limits 0-50°C
Pressure Limit 0-50 psig
Flowcell Material Clear Acrylic constant head overflow standard
Sealed acrylic flowcell optional
Sample Flow Rate 7-15 GPH

Ordering Information

For pricing Model Q46H/62-63 Residual Chlorine Dioxide Monitor please call AFC International at 800-952-3293, 219-987-6825 or fax 219-987-6826 or email


Model Q46H/62-63 Residual Chlorine Dioxide Monitor datasheet

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