Operation in Rain or Sleet

TM 3-6665-225-12

NOTE

c. Pull rainshield (13) from adapter (14). Screw

If M43 detector unit horn does not sound,

rainshield (13) into handle (2).

d. Unscrew AIR INLET assembly plug (1, fig. 2-8).

disconnect power source from 24 VDC

e. Screw adapter (14, fig. 1-3) into AIR INLET

INPUT connector, and repeat (22) through

assembly cover (3, fig. 2-8).

(26) above twice, if necessary. Use a new

filter each time. Then refer to table 3-3 for

NOTE

When using FLOWMETER (2, fig. 2-6), in-

operator's troubleshooting information.

(27) Disconnect power source connector from

stall FLOWMETER over adapter (2, fig.

2-8). When removing FLOWMETER, turn

M43 detector unit 24 VDC INPUT connector (11,

fig. 1-2).

it clockwise and pull from adapter.

f. If air temperature is 40F. or above, perform

(28) Immediately continue operation by per-

forming the procedures of paragraph 2-9r through

procedures of paragraphs 2-7 through 2-9.

g. If air temperature is below 40F. proceed to

paragraph 2-15b.

NOTE

The alarm system is now operational.

2-18. Operation in Blowing Sand or Dust

2-16. Operation in Rain or Sleet

CAUTION

Do not remove bottom case assembly

NOTE

After separating M43 detector unit bottom

(9, fig. 1-2) or air filter (3, fig. 2-4) in

presence of blowing sand or dust. Per-

case assembly and detector assembly, posi-

tion bottom case assembly with its bottom

form preoperational procedures (para 2-6)

in a sheltered area such as inside a build-

up to keep inside as dry as possible. Also

shield components mounted under detector

ing, inside of a vehicle, or under a lean-to.

assembly with the body as much as possi-

Contamination of the components within

the M43 detector unit with sand or dust

ble.

will render it useless.

a. Perform preoperational procedures of para-

graph 2-6.

a. When bottom case assembly is removed, in-

b. Remove RAINSHIELD assembly (1, fig. 1-3)

spect for presence of sand or dust. Carefully remove

from handle (2).

any foreign material being careful not to damage

c. Unscrew AIR INLET assembly plug (1, fig. 2-8).

components.

d. Screw RAINSHIELD assembly (1, fig. 1-3) into

b. Before reassembling bottom case assembly (9,

AIR INLET assembly cover (3, fig. 2-8).

fig. 1-2) and detector unit assembly (6), wipe seal (1,

fig. 1-4) and mating groove in detector assembly to

NOTE

When using FLOWMETER, pull rainshield

insure watertight and airtight seal when they are

assembled.

(5) away from adapter (2) and install

c. Replace air filter (3, fig. 2-4) at intervals pre-

FLOWMETER (2, fig. 2-6) over adapter (2,

fig. 2-8). Screw rainshield (13) into handle

scribed in table 2-1 using the following procedure.

(1) Disconnect power source from 24 VDC IN-

(2). To remove FLOWMETER turn it

PUT connector.

clockwise and pull from adapter. Remove

(2) Replace air filter with a new one. Make sure

rainshield from handle and install over

the Air Filter plug is tightly installed.

adapter.

e. If air temperature is above 40F., perform pro-

(3) Reconnect power source to 24 VDC INPUT

cedures of paragraphs 2-7 through 2-9.

connector.

f. If air temperature is 40F. or below, proceed to

(4) Check airflow (para 2-9h).

paragraph 2-15b.

d. If air temperature is 40F. or above, operation

is the same as under usual conditions, starting with

2-17. Operation in Snow

preoperation procedures (para 2-6).

a. Perform preoperational procedures of para-

e. If air temperature is below 40F., operation is

graph 2-6.

as prescribed in paragraph 2-15.

b. Unscrew RAINSHIELD assembly (1, fig. 1-3)

from handle (2).

2-14

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