H-25C Instruction Manual
Instruction 3015-0216
43
5. MAINTENANCE
Regular maintenance of your H-25C is required to maintain its performance. This chapter explains how to perform
scheduled periodic replacements of consumable items and those parts that are known to deteriorate over time. For
guidance on what to do in the unlikely event trouble occurs due to other causes, see Chapter 6.
Note that you should always turn the power switch OFF before starting any maintenance work.
5.1 Replacing the Probe Filter
Air (and measured gas) is drawn in through the probe at a rate of about 4.5 ml/s. Any dust drawn in by the air is
removed by the probe filter. When the material removed begins to clog the filter sufficiently that a condition in which
the flow drops to around 1/4 that rate continues longer than 30 seconds, " AIR FLOW " will appear on the display.
(Note that " AIR FLOW " may also be displayed for other reasons.)
If "AIR FLOW" is displayed, first make a visual check of the probe filter. If it is dirty, replace it the filter has directivity.
Attach it with its smooth surface on the side of the tube for introducing gas.
If "AIR FLOW" is still displayed even after you have replaced the filter, the cause may be one of the following.
•
Suction pump malfunction
•
Problem in the instrument internal tubing
•
Flow sensor malfunction
See Chapter 6 for instructions on how to check for these problems, and what action to take.