TM 10-6665-297-13&P
3-3.2
ALARM CIRCUIT ADJUSTMENT (continued)
4.
Turn screw adjustment of ALARM potentiometer (R29 for CD800/830 Systems; R41 labeled "A" for
CD802/832 Systems) fully counter-clockwise until alarm relay energizes and ALARM light comes on
(after two-second delay past trigger point).
5.
Push and hold down RESET button and turn ALARM potentiometer adjustment screw slowly
clockwise until ALARM light goes off. (Time delay circuit does not operate as light goes out and relay
de-energizes. )
6.
Turn screw adjustment of ZERO potentiometer until ALARM light goes on, signifying an energized
alarm relay. Note percent L. E. L. meter reading at this point.
7.
Repeat steps 2 through 5 for fine adjustment of alarm relay trigger point.
NOTE: If adjustments do not result in setting alarm response level at the desired percent L. E. L.
meter reading, refer to TROUBLE-SHOOTING procedures in Section 4.
8.
Return screw adjuster of ZERO potentiometer to setting that re-zeros indicating meter pointer after
confirming that detector is sampling gas-free air.
3-3.3
TEST ADJUSTMENT. The TEST pushbutton, when depressed, closes a circuit to ground through
one lead to differential amplifier U3, thus impressing a voltage equivalent to that which would appear
on the lead if the detector were sensing a gas-air mixture of 100 percent L. E.L. Adjust test circuit to
obtain a full-scale meter reading (100 percent L. E. L.) as follows:
1.
Press TEST pushbutton and observe deflection of meter pointer.
2.
If reading is less than full scale, or if pointer rapidly swings to a mechanical stop, turn screw adjuster
of RANGE potentiometer R22 on control module printed circuit board (CD800X: located on narrow
flange below opening at left inside circular window) to obtain a full-scale meter reading with TEST
pushbutton depressed.
3.
Observe WARN and ALARM lights. Both should go on as TEST push-button is depressed, and
warning and alarm relays should energize. If not, set WARN and ALARM adjustments in accordance
with paragraphs 3-3.1 and 3-3.2.
23-9617
7/1/76
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