ANSWER KEY AND FEEDBACK
Correct Answers and Feedback
Two and four ports.
There are two configurations for relief valves. They are two- and four-port and are used to
relieve pressure. A four-port relief valve is for connecting additional plumbing that may be
incorporated into a more complex hydraulic system. (Page 50)
A pressure reducer provides the different pressures which are required to operate some
components. (Page 51)
There are only two types of pressure switches used in Army aircraft. (Page 52)
Pressure relief valve.
In a pressure relief valve, when fluid pressure reaches a certain point, the relief valve opens
to relieve excessive fluid pressure, allowing it to return to the system reservoir. (Page 50)
This switch senses any under- or over-pressurization of hydraulic fluid. (Page 52)
Pressure reducer valve.
The pressure reducer valve senses abnormal pressure buildup and opens to relieve the
excessive pressure. (Page 52)
A pressure switch activates a warning device at a predetermined fluid pressure. (Page 52)