Balancing The Sensor Optics - GE HumiLab Operator's Manual

Balancing the
sensor optics
Chapter 5 — Maintenance and Troubleshooting
when an "S" appears on the status display, indicating that service is
required.
Under normal conditions, the chilled mirror hygrometer is
self-checking and self-balancing. However, there are occasions
when particulate matter and water-soluble contaminants reduce
sensor mirror reflectance and system accuracy. Clean the sensor
mirror according to the procedure below.
1. Deactivate the sensor cooler by setting the Electronics front
panel Sensor switch to the
2. Open the sensor by removing the sensor cover.
3. Moisten a cotton swab with a cleaning solution suitable for
mirrors, such as the blue cleaning solution in the GE General
Eastern maintenance kit, or dilute methanol or rubbing alco-
hol.
Do not use Q-tips or other swabs that contain oils.
4. Clean the mirror with a few light wipes. If the sensor has been
exposed to significant contamination, clean the other optical
surfaces in the sensor and the sensor cavity itself.
5. Replace the sensor cover. Leave it in the Open position, with
the large holes allowing maximum air into the sensor cavity
for fastest response time.
6. Return switches to normal, initiate a Pacer cycle, and continue
operation.
If the service ( "S" ) flag reappears after a Pacer cycle, even after
performing the mirror cleaning procedure above, check the sensor
optics balance adjustment. Improper adjustment of the optical
balance is the most common cause of instrument malfunction.
Also, new systems may require an optical balance adjustment after
one or two months of operation.
Never perform the Optical Balance Adjustment without first clean-
ing the mirror.
Place the sensor switch on
segment display. If only the bottom segment bar is lit, the sensor is
properly balanced. Otherwise, balance the sensor according to the
procedure below.
HEAT position.
HEAT , wait one minute, then observe the
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