Det-Tronics C7052J UV/IR Flame Detector used with R7494, R7495 Controller - Manual (Page 22)

(sometimes barely detectable to the human eye) can
significantly reduce the sensitivity of the detector. The
windows and
oi rings should be thoroughly cleaned on
a regular basis. The length of time between periodic
cleanings will be determined by the nature and amount
of contaminants present in the environment.
Remove the oi rings by squeezing the tabs together
and pulling away from the detector. Clean the viewing
windows thoroughly, all the way to the edge. Also clean
the reflective surface of the
oi rings (the surface of the
ring that faces the detector viewing window). When re-
installing an
oi ring, hold it by its tabs to avoid leaving
fingerprints on the reflective surface. Re-install the ring
so that the opening is pointed down to prevent a
buildup of contaminants. If corrosive contaminants in
the atmosphere cause the reflective rings to deteriorate
to the extent that it is no longer possible to restore them
to their original condition, they must be replaced.
Det-Tronics window cleaning solution (part number
001680-001) is designed specifically for cleaning the
optical surfaces of the detector. DO NOT use commer-
cial cleaners. These products can leave a residue on
the surface that is intended to give it a “sparkling” look,
however, this residue can substantially attenuate the
radiation reaching the sensor.
Use a clean cloth or tissue to clean the window. DO
NOT use commercial glass cleaning tissues, since
many of these contain a silicone substance that remains
on the window after cleaning. Silicone readily absorbs
radiation and can effectively “blind” the detector, even
though the window appears to be clean.
NOTE
When cleaning the detector windows, remove input
power or place the system in the “Bypass” or
“Reset/Inhibit” mode. Rubbing motion on the sur-
face of the windows during cleaning can create an
unwanted output activation.
Viton O-rings on each of the detector housings are used
to ensure the watertight integrity of the detector.
Periodically, the housing should be opened and the O-
rings inspected for breaks, cracks, and dryness. To test
them, remove the rings from the detector housing and
stretch them slightly. If cracks are visible, the ring should
be replaced. If they feel dry to the touch, a thin coating of
lubricant should be applied. When re-installing the rings,
be sure that they are properly seated in the groove on the
housing. It is imperative that these O-rings be properly
installed and in good condition. Failure to maintain these
rings can allow water to enter the detector and cause
premature failure. The life expectancy of Viton O-rings
can vary considerably, depending on the amount and
nature of contaminants that are present in the environ-
ment. The individual responsible for maintenance of the
system must rely on experience and common sense to
determine how frequently the rings should be inspected.
The recommended material for lubricating the O-rings is
a silicone free polyalphaolefin grease, part number
005003-001, available from Detector Electronics. A
coating of lubricant should also be applied to the
threads on the sensor housings before reassembling the
detector. This will both lubricate the threads and help to
prevent moisture from entering the detector housing.
Refer to “Recommended Spare Parts” in the “Ordering
Information” section of this manual for a list of products
available from Detector Electronics for maintenance of
the detector.
Sensor Module Replacement Procedure
To replace a defective module:
CAUTION
Do not open the detector housing in a hazardous
location without first removing power.
a. Remove power from the detector.
b. Remove the sensor housing (see Figure 12).
c. Remove the sensor module.
d. Determine the proper orientation for the new
sensor module (with the oi test lamps posi-
tioned at the top or side of the detector), then
install the module. Attach the connector plug
(DE5500 models of the IR sensor only).
e. Ensure that the O-rings at the base of the sen-
sor housing are positioned correctly and in
good condition. (Refer to the “Maintenance”
section of this manual for complete informa-
tion regarding care of O-rings.)
f. Re-install the sensor housing. Hand tighten
the sensor housing into the base until the O-
ring is fully seated to ensure explosion-proof
and watertight integrity of the housing.
g. Inspect the viewing windows and oi rings and
clean if necessary. Also check the position of
the
oi rings.
h. Perform the “Startup Procedure” before return-
ing the system to normal operation.
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