64
O&M Manual
Rev-F (8/17)
Part 8 – Maintenance and Troubleshooting
8.1
System Checks
1.
If the FAIL icon is flashing on the display, check the Fault List to determine the cause of the
failure. To access the Fault List, press the MENU/ESC key until the DIAG menu appears.
Then press the UP arrow key until the Fault List appears. Press the ENTER key to access
the Fault List, and the highest priority fault message will be displayed. For a list of all
messages and possible causes/solutions, see message table at the end of this section.
2.
In
ALL
environments, connect an earth ground jumper to earth terminal connection on
monitor.
3.
Perform a two-point calibration with two fresh buffers prior to sensor installation.
4.
Check sensor cable color to terminal strip markings.
5.
For highly unstable behavior, remove sensor from the process and measure the process
solution in a plastic beaker. If the reading now stabilizes, place wire in beaker solution and
actual process solution to determine if a ground loop exists.
6.
Verify that the black rubber shipping boot has been removed from the end of the sensor prior
to submersion. If the sensor has been left to dry out, allow sensor to be submerged in buffer
or water to re-hydrate for at least 4 hours. The saltbridge may need replacement if the
sensor has dried out for too long.
7.
If the instrument 4-20 mA output is connected into other control systems, disconnect output
loop from system load and run through a handheld DMM to monitor current. Verify that the
system operates correctly in this mode first.
8.2
Instrument Checks
1.
Remove sensor completely and connect 1100 Ohms from the yellow to black sensor input
leads. Make sure the unit is configured for a Pt1000 thermal element and that the
temperature is not in manual locked mode. Also, connect a wire jumper from the red cable
lead input to the green cable lead input. The temperature reading should be approximately
25°C, the pH reading should be approximately 7.00 pH, and the sensor mV reading should
be between -20 and +20 mV.
2.
With a DMM, measure the DC voltage from the white sensor lead connection to the black
sensor lead connection. With the positive DMM lead on the white wire, the meter should read
between -4.5 and -5.5 VDC.
3.
With power disconnected, unplug the fuse from the power supply board and verify continuity
across the fuse.
