(3) _Pressure-valve handle and valve flexible shaft._ (Figs 33 and 34) The pressure-valve handle is held by a small nut on the end of the valve flexible shaft, which in turn is connected to the pressure-tank valve by means of the valve stem and a large hex nut. The handle and shaft extend to the right of the tank group, enabling the firer to open and close the valve without assistance when carrying the weapon. The handle slips over the end of the shaft and is held to it by a nut. The shaft is held to one of the fuel tanks by a clamp, nut, and bolt welded to the tank. (4) _Check valve._ (Figs 33 through 35) The check valve has the same function as the valve on a vehicular tire tube, but it is much heavier in construction and different in design because the pressure in the flame thrower is 50 times greater than that in an automobile tire tube. Connected by threads to the pressure valve, the check valve permits compressed air or nitrogen to enter the pressure tank during charging (Pars 31 and 32) but prevents its escape when the outside source of pressure is removed. The cap is removed from the check valve only for charging or testing. _b. Removal._ (Fig 33) To prevent damage to threads, leaks, and loss of pressure and range, remove pressure tank and valve assembly only when necessary. [Illustration: Fig 33. Pressure system disassembled, showing nomenclature and Chemical Warfare Service stock numbers for requisitioning spare parts.] (1) _Release of pressure._ Be sure all pressure has been released from the pressure system before disassembling or removing any part or assembly of the pressure system. To release pressure, operate fuel valve (Par 26) and hold open until pressure is exhausted. As an added precaution, personnel should avoid facing the connections when disconnecting parts or assemblies. (2) _Removal procedure._ After release of all pressure: (_a_) Loosen the clamp from the valve flexible shaft. (_b_) Using wrench, unscrew the large hex nut which holds the flexible shaft on the pressure-tank valve. (_c_) Pull the valve flexible shaft and handle free of the valve. (_d_) Using wrench, unscrew the flared tube nut on the regulator tube adjacent to the pressure-tank valve. (_e_) Open pressure-tank clamp (Fig 39) and swing clamp strap outward. (_f_) Remove the pressure tank together with the pressure-tank valve and check valve. (_g_) To remove valve handle, use the adjustable-end wrench to loosen and remove nut from threaded outer end of valve flexible shaft. Slide out the valve handle. [Illustration: Fig 34. Lower portion of pressure system, assembled.] [Illustration: Fig 35. Check valve (cross section).] _c. Installation._ (Figs 33 and 39) To install: