Chiller Controller


The SZ2166 is a microprocessor based chiller
controller. It is designed for use on multi-stage chiller
applications and includes boiler support and control.


• Stand-alone or network operation • 365-day time clock with two holiday schedules, automatic leap year and daylight savings correction • No backup battery required for control parameters, schedule or clock • Hot water supply and return temperature inputs • Chilled water supply and return temperature input • Two digital outputs for boilers • One digital output for alarm • Mixed water temperature input • Outdoor air temperature input • Separate set point for thermal storage sequence • Outdoor air reset control • Two digital inputs for pump status • External time clock input • Six digital outputs for chillers, pumps and chiller stages • Adjustable offsets and differentials on digital outputs • Lead/Lag sequencing of up to six chillers • Two modulating analog outputs for valves and VFDs • Adjustable P+I+D control on modulating outputs • LEDs for monitoring status • Automatic rotation of pumps • Automatic rotation of chiller and boiler stages • Pump lube feature • Local and remote override capability

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Specs & Docs


General Accuracy: +/- 0.5% Programming: EIA RS485 interface Communications: RS485, half duplex Memory backup: Non-volatile EEPROM, no battery required Environmental Operating temperature: 32 to 131°F (0 to 55°C) Operating humidity: 0 to 100% RH, noncondensing Storage temperature: 14 to 140°F (-10 to 60°C) Electrical Supply voltage: 24 VAC +/-20% Inputs: Six 1000 Ω PtRTD, momentary override and five digital (dry contact) Range: Chilled water supply and return: 0 to 100°F Hot water supply and return: 40 to 240°F Mixed water: 20 to 220°F Outdoor air: -40 to 160°F Outputs: Nine digital (SPST dry contact, 24 VAC @ 2A) and two 4 to 20 mA DC analog Max. load resistance (analog output): 600 Ω Common mode rejection: 100 db @ 60 Hz Power consumption: 15 VA max. Specifications subject to change without notice.