Det-Tronics U7602B-P Unitized UV Flame Detector/Controller - Manual (Page 16)

FIRE RELAY TIME DELAY ADJUSTMENT
Unless specified otherwise, the time delay for the Fire
relay is factory set for 5 seconds. To change the delay
setting of the Fire relay, follow the procedure below.
NOTE
Adjusting the time delay for the Fire relay in a haz-
ardous location requires making the area temporar-
ily non-hazardous or disconnecting the input power
before removing the U7602 housing to make the
adjustment, and re-assembly of the housing before
applying input power to check the new setting.
1. Disable any alarm and extinguishing equipment
being controlled by the U7602.
2. Turn a UV source (such as the Det-Tronics model
W8066 UV Test Lamp) on or, if the oi feature is
being used (a switch wired between the oi TEST
terminal on TB1 and circuit ground), press the oi
test button and begin timing. The Fire relay will
energize after the time delay has expired.
3. If it is necessary to adjust the time delay, remove
input power to the U7602.
4. Remove the controller module housing. See
Figure 1.
5. Adjust the time delay potentiometer (refer to Figure
19 for location) using a screwdriver. To reduce the
time delay, turn the potentiometer counterclock-
wise (ccw). To increase the time delay, turn
potentiometer clockwise (cw). Small adjustments
make significant changes in the time setting
(approximately 1 to 2 seconds per 1/4 turn).
WARNING
If the U7602 is in a hazardous location, re-install
the controller housing before turning power on.
6. Apply input power to the U7602.
7. Repeat steps 2 to 6 until the desired time delay is
achieved.
8. Re-install the U7602 controller module housing, if
not done in a previous step. Ensure that the
housing is tightened with the O-ring fully seated to
maintain the watertight and explosion-proof
integrity of the detector.
9. Turn on all extinguishing equipment that is con-
nected to the system.
MAINTENANCE
The U7602 requires no periodic calibration. However, to
maintain maximum sensitivity, the viewing window must
be kept clean at all times. The length of time between
periodic cleaning will be determined by the nature and
amount of contaminants present in the environment.
Remove the oi ring from the detector housing and
clean the viewing window thoroughly, all the way to
the edge (see Figure 18). Also clean the inside of the
oi ring. When re-installing the reflective oi ring, hold it
by its tabs to avoid leaving fingerprints on the reflec-
tive surface. Re-install the ring so that the opening is
not aligned with the oi test lamp on the detector mod-
ule (indicated by a very small hole at the edge of the
detector module’s top surface). The opening in the oi
ring should be pointed downward 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.
To clean the window, use a clean cloth or tissue and
Det-Tronics window cleaning solution.
NOTE
Remove input power when cleaning the detector
windows to prevent unwanted output activation.
Rubber O-rings are used to ensure the watertight
integrity of the detector housing. Periodically, the
housings should be opened and the O-rings inspect-
ed for breaks, cracks or dryness. To test the O-rings,
remove them from the detector housing and stretch
them slightly. If cracks are visible, they should be
replaced. If they feel dry to the touch, a thin coating
of lubricant should be applied. When re-installing the
O-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 properly maintain the O-rings can allow
water to enter the housing and cause premature fail-
ure. The life expectancy of rubber O-rings can vary
considerably, depending on the amount and nature of
contaminants that are present in the environment.
MOUNTING SLOTS
TIME DELAY ADJUSTMENT
MOUNTING SCREWS
A1505
Figure 19—Controller Module Showing Time Delay Adjust
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