/ Ci4000 / Ci5000 Weather-Ometer
®
Service Guide Doc. No. 07-7030-00 Rev. 0
181
8.0 REPAIR & REPLACEMENT PROCEDURES
Sensor
Housing
Interference
Filter (Note
orientation of
arrow)
DO NOT remove
screws in this location
A10 Photodiode
Sensor Cell
Filter Housing
Cap
Sensor
Housing Cover
8.2 Sensor Replacement (cont.)
8.2.7 Light Monitor Photodiodes (cont.)
Figure 8.2 – 9 Older Ci4000 Single Bandwidth
Light Sensor
Guidelines
1) The photodiode is fragile. Handle it with care
and avoid touching its front window. If you do, clean
it with alcohol or optical cleaner and a soft cloth.
This applies to the interference filters as well.
2) Always ensure that the direction arrow on the
340 or 420nm filter is pointing toward the
photodiode (direction of light travel) when
assembling the light sensor. The 300-400nm filter
may be installed either way.
3) DO NOT attempt to install a photodiode normally
used with the 340/420nm filter in place of the one
used with the 300-400nm filter, or vice versa. The
spectral response of each is different and will result
in erroneous readings.
8.2.8 Chamber Overtemperature Thermostat
This thermostat is accessed from inside the
electronics drawer (but may be easier to replace
by removing the right-side access panel).
Guidelines
1) The face of the thermostat must be in contact
with the exterior wall of the test chamber. Apply a
small amount of silicon thermal grease to the face
of the thermostat when mounting a new one.
(Thermal grease is commonly used in the
electronics industry when mounting transistors to
heat sinks to improve thermal transfer.)
2) Apply sealant to the mounting screws. The
screws extend into the test chamber and could
allow leakage without sealant in place.
8.2.9 Chamber Overtemperature Sensor
(Older Ci4000 only)
On some of the early Ci4000 instruments, a
Chamber Overtemperature alarm was included
beside the Lamp Cooling Water Controller in the
top section. It has an RTD temperature sensor
mounted in the test chamber.
Replace the three-wire
sensor by disconnecting it
from the back of the alarm.
Remove the old sensor
from the test chamber
taking note of its insertion
depth in its mounting. Install
the new sensor.
C
h
a
m
b
e
r
W
a
ll
Reset
Figure 8.2 – 10 Chamber Overtemp. Thermostat S4
Eurotherm 92
0000
AL1
AL2
RESET
Chamber Overtemperature
Figure 8.2–11 Chamber
Overtemperature Alarm