Which of the following conditions would cause the 81AF, nonsurge check valve, to open too rapidly or have no control of the opening rate?
A. A loose diaphragm washer
B. Air in the main cover chamber
C. A swing check valve disc not seated
D. An obstruction between the disc and the seat of the main valve
This question is part of 3E451 Volume 2 WFM Fundamentals, Valves, and Pumps