Question 280General Subjects - QMED

The correct answer is A) Excessive suction lift. Excessive suction lift can prevent a steam reciprocating pump from delivering its rated capacity. When the suction lift is too high, it can cause cavitation and reduce the pump's ability to draw in and discharge the full volume of fluid. This occurs because higher suction lift creates lower pressure on the suction side, which can lead to the fluid vaporizing and forming air bubbles that disrupt the pump's operation. The other options, while potentially problematic, are not the primary reason a steam reciprocating pump would fail to deliver its rated capacity. A leaking snifter valve (option C) could introduce air into the suction side, but this is not the main factor limiting the pump's performance. Air in the discharge expansion chamber (option B) may impact efficiency, but would not completely prevent the pump from reaching its rated output.