eL-720 User’s Guide
3
PROBE FILTER
The probe filter prevents dust and moisture from contaminating the
optical characteristics of the sensor. It should be replaced periodically.
Occasionally, the filter may become obstructed with dirt, dust, or
moisture. To determine if air is flowing properly into the
eL-720
sensor,
gently exhale near the probe tip. The human breath contains enough
CO
2
to cause a full alarm in high sensitivity mode. If the unit does not
alarm, replace the filter.
If the filter has become moist due to exposure to water or
condensation follow this procedure to prevent moisture from
contaminating the sensor:
1. Using a paper towel or shop rag, dry any moisture at the probe tip
prior to unscrewing the probe tip cap.
2. Unscrew the probe tip cap to expose the filter.
3. With a paper towel or shop rag, soak up any excess moisture that
may have collected on the filter and filter holder prior to removing the
filter. Also thoroughly dry both inside and outside of the probe cap.
4. Remove and discard the old filter, and replace with a new one.
5. Reassemble the probe tip cap. The unit is now ready for operation.
Failure to dry the filter parts as described above may result in
further contamination of the new filter, and the possibility of
residual moisture being drawn into the optical sensor, causing a
failed sensor alarm.
If moisture is suspected of being drawn into the
sensor, clean the probe and sensor as described on page 4.
