Refer to the drawing of a water supply pump with two suction sources (see figure below). All motor-operated valves (MOVs) are currently closed.
Which one of the following MOV interlocks will permit the pump to take a suction on either the building sump or the water storage tank, while preventing the two sources from being cross-connected?
A. Neither MOV-1 nor MOV-2 can be opened unless MOV-3 is fully closed.
B. None of the MOVs can be opened unless at least one MOV remains fully closed.
C. None of the MOVs can be opened unless at least two MOVs remain fully closed.
D. Neither MOV-1 nor MOV-2 can be opened unless the other source MOV is fully closed.
Show Answer
Answer: D
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