Teledyne 311 - Portable trace oxygen analyzer - Manual (Page 12)

4. MAINTENANCE
4.1 Battery Power Supply Service. The Model 311 is designed to be intrinsically
safe, and therefore is for use ONLY when it is not connected to the AC power line. TAI suggests
that an overnight recharge be accomplished every four (4) weeks of continuous use. To recharge
the batteries, place the range switch in the “OFF” position and connect the power cord to a
convenient outlet. NOTE: The amber charge lamp (back of case) will be lit during charging.
The integral charging circuit will automatically energize and regulate the battery charging
current when the switch is in the “OFF” position and the AC cord is plugged into the power
line.
WARNING: DO NOT TURN THE RANGE SWITCH EITHER TO “BATT TEST” OR
TO ANY OF THE OPERATING RANGE POSITIONS WHILE THE UNIT IS PLUGGED
INTO THE POWER LINE! DOING SO MAY CAUSE THE INTEGRATED CIRCUITS
TO FAIL.
When recharging is completed, unplug the unit from the AC outlet. Turn the range switch to the
“BATT TEST” position or to the operating position.
NOTE: The “BATT TEST” position will not give a reliable indication of the battery
charge immediately after a charge cycle. Allow the unit to run for awhile before testing the
batteries.
If the instrument is stored with the range switch in the “OFF” position (charge cord
disconnected), the period of time between charge periods is extended from one month to four
months. However, do not leave it longer than this time period.
4.2 Routine Maintenance. Beyond adhering to a battery recharge schedule, no
routine maintenance is required, as there are no moving parts in the instrument other than the
meter movement. The Micro-Fuel Cell is a sealed, modular component that should be replaced
only when faulty.
4.3 Cell Replacement. The characteristics of the Micro-Fuel Cell are similar to those
of a mercury battery in that both provide an almost constant output through their useful life, and
then fall off sharply towards zero at the end. If the sample being analyzed has a low (X1 range)
oxygen concentration, cell failure will probably be indicated by the inability to properly calibrate
the analyzer. The user will find that very little adjustment of the 10-turn span potentiometer will
be required to keep the analyzer calibrated properly during the duration of a given cell’s useful
life. If large, many turn adjustments (cw) are required to calibrate the instrument, or calibration
cannot be achieved within the range of the control, the cell should be immediately replaced (read
Section 5.4 before replacing cell).
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