Electro-Chemical Devices (ECD) DCA-23 - Manual (Page 22)

Page 16 DCA-23 Dechlorination Analyzer
5.0 MAINTENANCE
The DCA-23 output should be verified weekly against an approved method like a DPD test. Inspect the
flow train for leaks or a buildup of debris in the pipes prior to testing the sample. There are no
consumable components aside from the pH electrode and the TRO electrode and these should be
replaced yearly.
5.1 Chlorine TRO Sensor
When used in chlorinated water, TRO sensors require little maintenance. TRO sensors do require
periodic calibration due to drift in the reference electrode as it ages. This aging causes the displayed TRO
value to be lower than the true mV value of the sample.
Check the sensor on a monthly basis, recalibrate if necessary. Clean or replace the pH sensor when it
becomes noisy and slow to respond.
If the sensor needs cleaning then it can be soaked in a dilute solution of HCl, 1-5%, for 10-30 minutes.
This will remove scale or biofilms from the sensor, rinse well and soak in pH 4 buffer for 15 minutes
before returning the sensor to service.
5.2 pH Sensor
When used in chlorinated water, pH sensors require little maintenance. pH sensors do require periodic
calibration due to drift in the reference electrode as it ages. This aging causes the displayed pH value to
be higher than the true pH of the sample.
Check the sensor on a monthly basis, recalibrate if necessary. Clean or replace the pH sensor when it
becomes noisy and slow to respond.
If the sensor needs cleaning then it can be soaked in a dilute solution of HCl, 1-5%, for 10-30 minutes.
This will remove scale or biofilms from the sensor, rinse well and soak in pH 4 buffer for 15 minutes
before returning the sensor to service.