(6) Fully charge pressure tank. ([Par 32])
(7) If test firing with fuel, load ignition cylinder. ([Par 18])
(8) Open pressure-tank valve and simultaneously observe pressure in fuel tanks by reading gage. The gage indicates the pressure in both tanks. It should be between 350 and 390 pounds per square inch.
(9) Read the gage at the expiration of not less than 5 minutes. The tanks should have a pressure reading of not more than 390 pounds. If the pressure continues to increase beyond 390 pounds and the safety head blows, replace the safety head and the pressure regulator.
(10) Fire by operating controls (or simulate firing if tanks are filled with water). The burst should last 3 seconds, during which time the pressure should not drop below 260 pounds.
(11) If the pressure does not conform to the requirements stated in (8), (9), and (10), adjust the pressure regulator upward or downward. ([Par 67 d])
(12) While the above test firing is proceeding, check for leaks at all joints and connections on the tank group. The pressure system should be checked by painting the joints with soap-and-water solution and by looking for bubbles which indicate leaks. For replacement of parts where pressure leaks, see Paragraph 66. Fuel leaks may be seen without soap and water. For repair of fuel leaks, see Paragraph 75 e. The nozzle should be observed by removing the ignition shield. Nozzle leaks are corrected by cleaning, adjusting needle ([Par 75 d]), or by regrinding. ([Par 75 e]) If this is not successful, replace both needle and barrel as a unit.
c. Fuel valve. Discharge all pressure from the gun by operating the fuel valve. Carefully remove the valve grip and grip support. ([Par 74]) Look for signs of leakage at the valve diaphragm. If a leak is present, replace valve-diaphragm assembly. (Pars [75 b] and [75 c])
d. Valve grip. Disassemble the valve grip ([Par 74]) and lubricate. ([Par 49])
e. Carrier. Tighten the carrier cord.