Question 192General Subjects - 1st Asst/Chief

The correct answer is A) The hydro-pneumatic expansion tank is operating with an insufficient air charge. The hydro-pneumatic expansion tank is responsible for maintaining consistent water pressure in the system. If the tank's air charge is insufficient, it will not be able to properly regulate the pressure, causing the pump to short cycle (turn on and off rapidly) in an attempt to maintain the desired pressure. The other options are incorrect because: B) A low water level in the hydro-pneumatic tank would not cause short cycling, it would simply result in the pump running continuously. C) A low water level in the potable water storage tank would not directly affect the pump's operation. D) Excessive wear on the pump's wearing rings would cause a decrease in pump performance, but would not lead to short cycling.