The first step when resetting the slide valves on a duplex reciprocating pump is to __________.

Correct Answer: Option D — place the steam pistons in the mid-stroke position

Setting slide valves requires precise alignment of the steam distribution mechanism. Placing the steam pistons at mid-stroke ensures that the valve gear is in a neutral position relative to the ports, providing a reliable reference point for adjusting the valve linkage to ensure equal steam admission and exhaust timing.