Det-Tronics R7495D UV/IR Flame Detection System User Manual

Page 24

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 seat-
ed in the groove on the housing. It is imperative that
these O-rings be properly installed and in good condi-
tion. 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 environment. The individual
responsible for maintenance of the system must rely on
experience and common sense to determine how fre-
quently the rings should be inspected.

The recommended material for lubricating the O-rings is
a silicone free polyalphaolefin grease, part number
005143-001, 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.

Remove power from the detector.

Remove the sensor housing (see Figure 12).

Remove the sensor module.

Determine the proper orientation for the new sensor
module (with the oi test lamps positioned at the top
or side of the detector), then install the module.
Attach the connector plug (DE5500 models of the
IR sensor only).

Ensure that the O-rings at the base of the sensor
housing are positioned correctly and in good condi-
tion. (Refer to the “Maintenance” section of this
manual for complete information regarding care of
O-rings.)

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.

Inspect the viewing windows and oi rings and clean
if necessary. Also check the position of the oi
rings.

Perform the “Startup Procedure” before returning
the system to normal operation.

TROUBLESHOOTING

Table 3 is intended to aid maintenance personnel in
locating the cause of a system malfunction. The
R7495D Controller and plug-in detector modules are not
designed to be repaired in the field. If repairs are need-
ed, the device should be returned to the factory.