H-25C Instruction Manual
Instruction 3015-0216
35
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Is the "AIR FLOW" Indicator On ? (Check in measurement mode)
The " AIR FLOW" indication tells you that the intake air flow is being reduced due to clogging of
the probe air filter, or some other cause.
Under normal conditions, the instrument will suck in a bout 4.5 ml/s of measurement gas from the
probe. If the intake flow remains below about one quarter of this value for about 30 seconds, "
AIR FLOW" will be displayed.
If "AIR FLOW" is displayed, replace the probe filter. If the intake flow does not recover even
though you have replaced the probe filter, then there is some other problem. (See Chapter 6.)
Note that even if “ AIR FLOW" is displayed, you may still be able to measure and calibrate
normally in some cases. However, even in such cases we recommend that you take
maintenance actions to restore intake flow to its proper value as soon as possible.
