Table 5-7.—Functions of Controls and Instruments Index No. Nomenclature Function 1 Air supply shutoff Used for turning on and shutting off the shop air supply to the valve. test stand. 2 High-pressure air Indicates the air pressure being applied to the hose undergoing gauge (0-2,000 psi). pneumatic test. A red follower pointer indicates the maximum pressure applied to the hose. A manual reset knob is provided for resetting the follower pointer to zero. 3 Regulated air pressure Indicates the regulated air pressure being supplied to the oil gauge (0-160 psi). boost pump or the air boost pump. 4 Selector valve. Selects regulated air supply for the oil boost pump (hydraulic testing) or the air boost pump (pneumatic testing). 5 ,6 High-pressure oil Indicates the hydraulic pressure being applied to the hoses gauge (0-2,000 and undergoing hydraulic test. A red follower pointer on each gauge 0-20,000 psi). indicates the maximum pressure applied to the hoses. A manual reset knob is provided on each gauge for resetting the follower pointer to zero. 7 Gauge shutoff valve. Provides a means for shutting off pressure to the 0-2,000 psi oil pressure gauge when using test pressures in excess of 2,000 psi. 8 Manifold bleed valve. Used for bleeding air from the test hoses and manifolds before applying full hydraulic test pressures. Also used to release hydraulic pressure in the test hoses and manifolds after test. 9 Manifold bypass valve. Bypasses the manifolds when turned on. Used to relieve pressure on the manifolds at the completion of test. 10 Fluid flow sight Provides a means for detecting air bubbles in the hydraulic oil gauges. passing from the bleed valve to the oil reservoir. 11 Air booster inlet valve. Used to turn on and shut off the unregulated air supply to the air boost pump. 12 Air pressure regulator. Used for setting the input air pressure to the oil boost pump during hydraulic testing to give the desired hydraulic test pressure. Also used for setting the input air pressure to the air boost pump during pneumatic testing to give the desired pneumatic test pressure. 13 Air booster shutoff May be turned off after pressure is built up in the test hose; it valve. holds the test pressure and permits the air booster to be shut down. 14 High-pressure air Provides a means for releasing the air pressure in the test hose bleed valve. after test. 15 Water shutoff valve. Used for turning on the water to fill the pneumatic test chamber. 5-21