Delivery Pipe Coupling

TM 3-1040-214-12

(8) Disconnect the quick-disconnect coupling

(10) Check the pressure reading on the

half (3, Fig. 4-5) from the pipe and cap assembly.

pressure gage. It should stabilize between 30 and 50

psi. The pressure regulator setting is 40 10 psi.

(9) Install the pressure gage between the

hose assembly and pipe and cap assembly.

(11) If pressure gage reading is less than 30

psi, repeat operations (7) to (10) above.

c. Adjusting Procedure.

(12) If pressure gage reading is above 50 psi,

(1) Perform the operation in b above.

close the pressure tank valve. Open the shutoff valve to

(2) Fingertighten

needle

valve

(1) and

vent pressurized air. Repeat operations (3) to (10)

needle valve (2) (Fig. 4-5).

above.

(13) Close the pres sure tank valve.

NOTE

(14) Open

the

shutoff

valve

vent

the

If there is a needle valve on the side

pressurized air.

of the pressure regulator, check to

(15) Check and test adjustment of pressure

see that the needle valve is tight.

regulator (d below).

NOTE

d. Testing Pressure Regulator After Adjusting.

Needle valve 1 and 2 should not be

(1) Close the shutoff valve.

removed; they are not interchangeable.

(2) Slowly open the pressure tank val ve and

(3) Loosen needle valve 1 slowly; four

check the pressure gage. If the gage indicates a

complete turns to allow pressurized air to escape from

pressure between 30 and 50 psi, the adjustment is

the dome.

correct.

NOTE

Discharge of air is indicated by a

NOTE

hissing sound.

If the pressure gage indicates a

pressure below 30 psi or above 50

psi, refer to c above.

(4) After hissing noise ceases, close needle

valve 1.

(3) Test fire the disperser. During test fring,

(5) Open the pressure tank valve slowly. If

the pressure gage reading is acceptable up to 90 psi. If

the gage indicates a rise in pressure, close the pressure

the gage reading exceeds 90 psi, perform the following:

tank valve immediately. A rise in pressure indicates that

the pressure regulator is defective.

(a) Close the pressure tank valve.

(6) If the pressure regulator is defecti ve,

(b) Open the shutoff valve.

perform the following operations:

(a) Close the pressure tank valve.

the

pressure

regulator

(b) Open the shutoff valve to relieve air

(para 4-32).

pressure in the agent section.

(d) Adjust

the

pressure

regulator

(c) Replace the pressure regulator

(c above).

(para 4-32).

4-37. Delivery Pipe Coupling

(7) If pressure gage indicates no rise in

Organizational maintenance personnel are authorized to

pressure, open needle valve 2 slowly about one half

replace the delivery pipe coupling.

turn. Air will escape at the needle valve.

(8) Open needle 1 very slowly until pressure

a. Removal.

gage indicates a pressure reading. Immediately close

(1) Purge the air in the pressure system

needle valve 1.

(para 4-10a).

(9) Close needle valve 2.

(2) Remove coupling (12, Fig. 4-6) from the

delivery pipe (13).

NOTE

b. Assembly.

The pressure reading on the pressure

gage will slowly increase until the

(1) Apply anti-seize compound or tape on the

pressure in the agent tanks is

delivery pipe threads (12).

stabilized.

(2) Screw the coupling (12) on the delivery

pipe threads and tighten.

4-25