Select the Single Speed Pump option to control constant speed pumps.
The Variable Speed Pump option provides control for variable speed pumps.
The chiller condenser water pumps temperature control loop for dedicated variable speed pumps modulates the pump speed to maintain a differential temperature setpoint of the chillers that are running while still maintaining minimum flow through the chillers that are running.
The chiller condenser water pumps
differential pressure control loop for headered variable speed pumps modulates
the pump speed to maintain a differential pressure setpoint while still
maintaining minimum flow through the chillers that are running.
Note: On systems that have variable speed condenser water pumping, the
minimum CW flow should be set sufficiently high to ensure proper cooling tower
flow. If this information is not available from the cooling tower manufacturer,
set the value to 80% of the rated flow.