Xylem DH-21 - Manual (Page 107)

Chapter 6
Maintenance/Trouble Shooting
DH-21
Maintenance/Trouble Shooting 6-1
6.1 Maintenance
The “W ATER LOG” was designed to be a low maintenance instrument. The batteries should be
monitored, and will need to be changed when the voltage gets below 5.5V. The “W ATER LOG”
was designed mainly to be used in an unattended mode to prolong battery life. If you use the
“W
ATER LOG” for long periods of time connected to a computer, or if you make rapid
measurements (less than 8 seconds) for extended periods of time, you will drastically reduce the
life of your battery pack. For such applications, you should consider using an external battery or
power supply. For questions concerning the use of an external power source contact the factory.
You should also monitor the desiccant packs and the dry air filter which are located in the
battery/dry air chamber. The frequency of maintenance is a function of the Relative Humidity in
your area. We recommend that you check the desiccant at least every 3 to 6 months while you
determine the necessary frequency of maintenance. (See section 2.3 “Accessing the Battery Pack
and Desiccant”) Dry desiccant will have a dark blue color and will turn pink as it becomes
saturated.
As with any precision instrument, the calibration should be checked on a regular basis. We
recommend that the “W
ATER LOG” be factory calibrated on a yearly basis in order to maintain
the highest level of accuracy. However, the “W ATER LOG” can be field calibrated. This can be
done using some pressure standard as a reference and the Slope and Offset coefficients to make
the required adjustments. The accuracy achieved by field calibration is a function of the
calibration standard and many other variables. A field calibrated instrument may not meet the
manufacturer's specification for accuracy.
6.2 Trouble Shooting
It is unlikely that this manual will ever contain trouble shooting tips to cover every problem that
will be encountered. Feedback from customers is very valuable and greatly aids in the quest for
constant product enhancement. Please feel free to call the factory for technical assistance and also
with solutions you have found to past problems.
Our experience with pressure transducers has taught us a lot about the problems associated with
field deployable equipment. The following list of problems and possible solutions will
undoubtedly grow with subsequent revisions of this manual and may be helpful to you.