Which of the valves listed for the device shown in illustration will be open while the unit is operating in the back flush mode? Illustration GS-0153

Correct Answer: Option C — valves "4" and "14"

During back-flushing, the flow path is reversed to dislodge accumulated contaminants from the filter elements. Valves 4 and 14 are configured to isolate the normal discharge and redirect the fluid flow through the filter in the opposite direction, effectively purging the debris out through the designated back-flush drain line.