Initial Startup Adjustments

TM 5-6640-213-14

3. Zero the indicating meter, use a small screw-

driver to turn the zero adjuster on the printed circuit board.

Turning the adjuster clockwise increases the reading.

4. Depress the warn/test button and verify an

up-scale meter reading. The warn and alarm lights should come on.

A 2-second delay on the alarm indication is provided.

(b) Initial Startup Adjustments.

1. Measure and adjust the detector voltage at

the remote detector head, and adjust the "volt" control in the

corresponding module as described in paragraph 3-5c.

Measure the detector voltage at the cabinet

as follows:

(a) With instrument power on, connect the

high-resistance, direct-current, voltmeter leads to the detector

voltage test points on the printed circuit board (terminals B).

Observe the polarity.

(b) Record the voltmeter reading. The

reading recorded is the detector voltage without resistance due to

detector lead length. This procedure provides a convenient means of

checking the detector voltage at any time without disassembling the

remote detector.

3. Expose the detector to a sample of combust-

ible gas. See that the meter reads up-scale and that the alarms come

on at the desired levels.

4. If the warn and alarm set points need to be

adjusted, proceed as follows:

(a) Make sure that the detector is in a

combustible gas-free environment.

(b) Remove the warn and alarm relays (first

and last relays) from the printed circuit board.

Both the warn and alarm lights should come on.

counterclockwise.

(d) Turn the zero adjuster on the control

module printed circuit board until the meter reads approximately 2

percent below the desired warn setting.

(e) Turn the warn adjuster slowly clockwise

until the warn light goes off.

(f) Turn the zero adjuster slowly clockwise and

see that the warn light comes on at the desired level (there is a

2-second delay on warn and alarm indication).

2-16