Advanced Air Handling Unit Controller


The SZ2182 is designed to control constant volume
and variable air volume air handling units that
require advanced control functionality such as
dehumidification, face & bypass control or humidity
& carbon dioxide sensor sharing.


• Stand-alone or network operation • 365-day time clock with two holiday schedules with automatic leap year and daylight savings correction • Discharge air sensor input with high and low limits and reset. • Hot deck/cold deck control with night zone option • Outdoor air sensor input with heating & cooling lockouts • Six stages for either heating or cooling • Modulating output for heating and/or cooling • Modulating economizer output with digital or analog enthalpy options • Modulating output for fan or damper control • Programmable minimum run times • Adjustable delay on power-up for soft starts • PID control options • Smart Recovery • Fifteen status LEDs • Remote setpoint capability • User setpoint adjustment limits • Local override and remote override capability • Carbon dioxide demand control ventilation • Auxiliary time clock output • Fan interlock safety option • Equipment monitoring inputs and indication • External time clock input • Dehumidification sequences with integrated or external reheat • Face & Bypass control sequence • Outdoor air humidity sharing capability • Carbon dioxide sensor sharing capability • Pre-occupied purge sequence • Heat pump control functions

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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 Program Setting: 2 events per day with 7 days per week and 2 holiday schedules (12 periods of up to 99 days each) Override: Programmable from 0 to 255 minutes Environmental Operating temperature: 32 to 131°F (0 to 55°C) Operating humidity: 0 to 100% RH, non-condensing Storage temperature: 14 to 140°F (-10 to 60°C) Electrical Supply voltage: 24 VAC +/- 20% Inputs: Six 1000 Ω PRTD, momentary override,  4 to 20mA analog and 5 digital (dry contact) Range: Space and Return: 20 to 120°F Discharge Air Temp: 20 to 220°F Mixed Air Temp: 20 to 220°F Outdoor Air Temp: -40 to 160°F Outputs: Eight digital (SPST dry contact, 24 VAC @ 2A), and four 4-20 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.