Xylem AquaBoost CS and VS Pumping Packages - Manual (Page 39)

When a low-suction or high-temperature thermal cutout situation occurs, the red light
indicator illuminates. An auto reset feature is provided in order to return the pumps to
operational state.
Variable speed operation
Variable speed simplex – for capacities up to 110 gpm
The pressure transducer monitors the system pressure and sends a feedback signal to the
controller. Depending upon the feedback, the controller then changes the speed of the
pump.
Condition Description
The system pressure falls below the set point. The pump starts automatically and pump speed
continues to ramp up until the system pressure satisfies
the set point.
The system pressure rises above the set point. The pump automatically reduces speed until the system
pressure reaches the set point, provided the minimum
run timer has expired.
Variable speed duplex – for capacities up to 220 gpm
The pressure transducer monitors the system pressure and sends feedback signal to the
controller. Depending upon the feedback, the controller changes the speed of the pump
or stages/de-stages the other pump.
Condition Description
The system pressure falls below the set point. The pump starts automatically and pump speed
continues to ramp up until the system pressure satisfies
the set point.
The system pressure rises above the set point. The pump automatically reduces speed until the system
pressure reaches the set point, provided the minimum
run timer has expired.
Low-suction pressure switch
Simplex and duplex units will run when there is demand unless the optional low-suction
pressure switch trips due to low city pressure.
The low-suction condition resets automatically when city pressure returns to an acceptable
level.
Temperature relief valve
The variable-speed units have a temperature relief valve that senses water temperature
inside the pump.
The valve opens and closes depending on the water temperature. This modulating action
maintains a relatively constant fluid temperature even as operating conditions vary.
Condition Description
The water temperature exceeds the valve opening
temperature, typically 120ºF (49°C).
The valve automatically opens to allow relatively cooler
supply water to refill the pump as the hot water is
discharged to the drain or low pressure return.
The water temperature falls below the opening
temperature by 10º F (5.5°C).
The valve automatically closes in order to conserve water
and reduce waste.
Commissioning, Startup, Operation, and Shutdown
AquaBoost CS and VS Pumping Packages Installation, Operation, and Maintenance Manual 37