YOKOGAWA PH450G

<4. Operation>
4-10
IM 12B07W01-04EN 1st Edition : Nov 11, 2016-00
(1) Turn on the MANUAL WASH switch in the control box to execute the WASH operation.
(2) Remove the sensor holder after the air bubbling in step 1 is completed.
Submerge the pH sensor in water. Leave the sensor in the water until the system is
restarted in order to prevent the glass lm on the sensor electrodes from drying out.
CAUTION
Always reinstall the cover which you have removed in order to remove the sensor holder from the
chassis. Particular caution must be taken if the system is installed in a location exposed to rain. A
wet terminal block of the limit switch will result in corroded cables.
(3) Turn off the MANUAL WASH switch and cut off the power supply.
(4) To prevent loss of the chemical solution in the KCl reserve tank during a system shutdown
over a prolonged period, close the pressure reduction valve for air that pressurizes the tank.
lf you are also shutting down the air supply, you need not close the valve.
4.4.5 Procedure When Restarting System Operation
Follow the instructions below when restarting system operation. If the system is restarted after a
prolonged shutdown, conrm that the chemical cleaning system is free from problems.
(1) If the air supply has been cut off, supply air at the specied pressure,
(2) Conrm the settings of each pressure reduction valve. Adjust them if they fail to indicate the
required readings.
(3) Attach the sensor holder to the cylinder of the PH8HS3 holder.
(4) Supply power to the chemical cleaning system.
(5) Turn on the MANUAL CLEANING switch in the control box to verify that the system
performs cleaning normally. Turn off the switch when you have completed verication.
(6) Calibrate the pH converter or the pH transmitter with a standard solution.