How does the no-flow shutdown work (Option X)?
The no-flow shutdown replaces the standard thermal bleed circuit on a pressure booster system. The aquastat, normally used to actuate a solenoid valve on the thermal bleed, is used to actuate the shutdown of the pumps. The logic behind this is that thermal build-up in the seal flush line of the pump indicates that the pump is operating at no-flow. The system is turned back on after a shutdown by a pressure switch. The setting on this switch is 5psi below the design system pressure. A loss of 5psi pressure on the system side will bring the lead pump back on.
