TM 55-4920-428-13
2-5. Hydraulic Unit Controls and Indicators.
CONTROL OR INDICATOR
DESCRIPTION
(Fig. 2-3)
FILTER indicator
Press to reset pop-out visual indicator. Extends to indicate that
differential pressure across filter element exceeds 45 psid
(contaminated filter). Bypass will occur at 87 psid.
SOLENOID valve (VP5)
The solenoid valve is electrically controlled by SOLENOID
SHUTOFF switch on the electrical unit and the SOLENOID
push-pull knob. Lamp inside knob lights to indicate valve is
open.
HIGH PRESS REGULATOR
valve (VP4)
HIGH PRESS gage (G1 )
HIGH PRESS SHUTOFF
VALVE (VP3)
HIGH PRESS RELIEF
VALVE (VP6)
RETURN SHUTOFF VALVE
(VR3)
LOW PRESS REGULATOR
(VR7)
LOW PRESS RELIEF
VALVE (VR8)
RETURN BACK PRESS
valve (VR4)
OPEN - Supply hydraulic pressure is connected to unit
valves.
CLOSE - Hydraulic pressure to unit is shut off.
Regulates fluid pressure to pressure controls of test set. Includes
3450 psig relief valve.
DECREASE - Fully open to return. Pressure at manifold is
250 to 350 psig.
INCREASE - Fully closed to return. Pressure at pressure
controls is supply line pressure.
0 to 5000 psi panel indicator. Indicates pressure downstream of
the HIGH PRESS REGULATOR.
Needle type valve with indicating scales. Controls flow to
pressure valves.
OPEN - Opens pressure passage.
CLOSE - Closes pressure passage.
Push-to-open 2-way valve. Opens pressure passage to return
system.
Spindle type valve with indicating scales. Blocks return flow
from return system.
O P E N
-
Opens return passage.
CLOSE - Closes return passage.
Regulates fluid pressure to return controls of test set. Includes
300 psi relief valve.
DECREASE - Fully open to return.
INCREASE - Fully closed to return. Applies pressure to
LOW PRESS gage (G2).
Push-to-open two-way valve. Opens return pressure passage to
return system.
Needle type valve with indicating scales. Controls pressure to
return selector valves.
OPEN - Fully open to return selector valves.
CLOSED - Fully closed to return selector valves.
2-7
