Precautions For Measurements - horiba TW-150 Instruction Manual

3 OPERATION
3.5

Precautions for Measurements

Switch to maintenance mode when opening the inner door.
Opening the inner door during measuring affects the values of turbidity and color
measurements. Do the following to avoid abnormal output or alarms.
Press [MAINTENACE] or [CAL.] and enter maintenance mode.
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Set maintenance-mode output to PRESET or HOLD.
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Reference
"5.2.2 Setting external output during operation" (page 79)
Install the device so that backpressure is not created in the cells
Backpressure in the cells may severely shorten the operational life of the pH sensor.
Backpressure is created if the drain pipe is located above the device, or if the drain clogs.
Clean the sensors and cells when they get dirty
If abnormal sample water is run through the device, the sensors and cells may get dirty.
Cleaning is required if dirt can be seen on the sensor. Contact a service representative.
Run sample water and wait until the measured values become stable
The measured values may be unstable for a while after sensor installation.
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The measured values may be unstable for a few hours after running color calibration
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solution (chloroplatinic acid) through the device.
Adjust the flow rate of sample water to 80 mL/min
The sample water flow rate affects measurement of the residual chlorine.
A dry flowmeter takes approximately two weeks to become stable
When using the device for the first time, or after stopping it for more than a week, it takes
approximately two weeks until the flowmeter becomes stable after running water through the
device. You are required to readjust the flow rate after the flowmeter becomes stable.
Replace the mesh filter periodically
Foreign particles in sample water can get clogged in the mesh filter and cause reduction of the
flow rate. The mesh filter should be replaced every three months; however, earlier
replacement may be required depending on the condition of the sample water.
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