AEC NEC Central Station Air and Water Cooled Chiller - Manual (Page 44)

NEC Series Water- and Air-Cooled Central Chillers Page 43
Set Temperature
Turn this potentiometer to the desired leaving water temperature. Normal operating range for
standard NEC chillers is 20°F to 65°F (0°F to 30°F on low temperature R-502 units). Please note
that the temperature scale on the graphic panel exceeds these ranges, but optimum operation is
achieved within the stated range.
Lead/Lag (Optional)
This optional toggle switch, available on NEC-2 and NEC-3 chillers, allows the operator to
distribute the service time between compressors. In the
LEAD position, Compressor #1 actuates
first when put under load, followed by #2 and #3 (if installed) as they are needed. In the LAG
position, Compressor #3 starts first, then #2, and finally #1 (if installed). Periodically change the
LEAD/LAG switch position to balance the service load between the circuits.