horiba HR-200, Instruction Manual

Page: 61 / 103

Maintenance
49

Check of residual chlorine concentration
This instrument measures residual chlorine without sample conditioning by reagent. The pH or
conductivity will affect measurement data. Check the residual chlorine of the sample water by
a DPD method tester for getting a reference concentration. Once a day is recommended.
Perform calibration whenever water quality is changed or after maintenance of the detector
(cleaning of the electrode or the cell, replacement of the electrode or beads) with a sampling
valve closed. If any maintenance are performed by shutting off the sample, span calibration is
needed.
Note

Sampling water should be discharged more than 500 mL from the sampling cock for flushing
before getting sample for a DPD tester.

The sampling cock fully open will reduce the flow rate to the measuring cell and make
measurement erroneous. Adjust the throttle to keep enough flow rate to the measuring cell.
Reference

Refer to “ Calibration ” (page 57).

Refer to “ Data ” (page 66).

Removal of sensor contamination
Physical abrasion by beads and electrochemical etching clean the surface of the cathode
electrode. If the sensitivity becomes lower and you find any metal remained on the cathode,
clean up the cathode surface manually by the following procedure.

Cleaning the cathode electrode
Operation
1. Check that the converter is OFF.
2.
Close the valve to shut off the sample.
3.
Loosen the sensor cap and take out the sensor holder.
WARNING
Caution strong acid
If nitric acid gets into the eye, irritation of the mucous membrane and even blindness may result.
In handling nitric acid, be sure to use protective goggles and mask. If nitric acid gets into the eye,
immediately rinse it out with plenty of water for more than 15 min, and then get medical care (In
rinsing out nitric acid, ensure that the eyeball and the eyelid are entirely exposed to water by fully
opening the eyelid with your fingers). If nitric acid remains in contact with body and clothes, chemical
burns may result. Therefore, if a spill or splashing occurs, immediately take off the clothes and rinse
off the nitric acid with plenty of water.
O-ring
Sensor cap
Sensor holder
Cathode electrode
h19136 | UTC 2020/03/30 3:34:51
CONFIDENTIAL