According to the illustration, which of the following conditions would most likely cause Pump "A" to short cycle? GS-0173

Correct Answer: Option A — The hydro-pneumatic expansion tank is operating with an insufficient air charge.

Short cycling occurs when the hydro-pneumatic tank lacks sufficient air cushion to maintain pressure. Without enough air, the water level rises rapidly, causing the pump to reach the cut-out pressure quickly and then restart immediately as pressure drops, leading to excessive motor starts and potential damage to the pump's electrical components.