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O&M Manual
Rev-B (7/15)
Part 6 – System Maintenance
6.1
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, refer to
Section 6.3.
2. Perform a two-point calibration with two fresh buffers prior to sensor installation.
3. Check sensor cable color to terminal strip markings.
4. 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.
5. 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.
6.2
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.
(NOTE: See sensor manual for specific sensor tests to be performed.)
