121
Prepare about 100 mL of a nominal 1% solution of hypochlorite (1 part commercial bleach with 4 parts deionized or
distilled water) and place this solution in a clean calibrator bottle. Install the bottle in the calibrator bottle position(s) you
use.
From the Service screen, Pumps tab, touch [Off] to turn on the pump for the calibrator bottle position to flush hypochlorite
solution through the pump tubing and calibrator well and to the waste bottle. After 3 minutes, touch [On] to turn the pump
off. Wait 10 minutes.
Remove and discard the hypochlorite solution, then rinse the bottle thoroughly with water. Next, add deionized or distilled
water to the bottle, reinstall the Cal bottle inside the bottle tray.
From the Service screen, Pumps tab, touch [Off] to prime the calibrator for 3 minutes to rinse the tubing and cal well with
water. After 3 minutes, touch [On] to turn the pump off.
Install a new bottle of calibration standard and mark the installation date on the bottle.
From the Service screen, Pumps tab, touch [Off] to prime the fresh calibrator through the tubing and cal well. After 2
minutes, touch [On] to turn the pump off.
Repeat this entire procedure for any additional calibrator bottle positions that you use.
Preventive Maintenance – 6 months or 1000 Hours
9.4
Before performing maintenance on the 2900 Series,
ALWAYS
turn the instrument off and unplug the power cord from the
wall outlet.
Perform the maintenance procedures in this section every 6 months or 1000 hours sample ready, whichever occurs first.
The YSI Preventive Maintenance Kit contains all supplies necessary. For the 2900D, use the 2988 PM Kit. For the
2950D, use the 2989 PM Kit.
9.4.1 Sample Module Cleaning
It is necessary to periodically clean the sample modules.
From the Service screen, [Sipper] tab, touch the button under Location. Select [Station 1-P96] to move the sipper to away
from the sample module.
Grasp the hand hold in the right side cover of the instrument and pull up and out to remove the cover.
Lift the cover off the left side of the instrument.
Unscrew the three thumbnuts on top of each sample module.
Figure 9.1
Thumbnuts
Sample module
Enzyme Probe
Enzyme Probe