Heat Pump Water Loop Controller



The SZ2161 is a microprocessor-based controller used to control water loops in heat pump-based plant control applications.



Six 1000Ω PtRTD, momentary override and five digital (dry contact)

  • Loop water supply and return: 20 to 120°F
  • Condenser water supply and return: 20 to 120°F
  • Boiler water: 40 to 240°F
  • Outdoor air temperature: –40 to 160°F


  • Twelve digital (SPST dry contact, 24 VAC @1A) analog
  • Two 4 –20mA DC

  • Stand-alone or network operation
  • 365-day time clock with two holiday schedules
  • Supply-and-return condensers for water temperature inputs
  • Outdoor air temperature input
  • Boiler supply water temperature input
  • Four digital inputs for status
  • External time clock input
  • Local override and remote override capability
  • Digital outputs for control of dampers, pumps, boiler stages, and mixing valves