Supply air tempering - Johnson Controls - LIT-12011950 - Building automation software - Smart Equipment Controller - 5.0

Smart Equipment Controls Sequence of Operation Technical Bulletin

Product name
Smart Equipment Controller
Document type
Technical Bulletin
Document number
LIT-12011950
Version
5.0
Revision date
2024-06-06
Product status
Active

Setpoints and related data

The setpoints and related data include the following items:

  1. Heating Control Type (Htg-Type) Proportional
  2. Hydronic Heat SAT Tempering Enabled (SATTempHydHt-En) Yes
  3. Hydronic Heat SAT Tempering Setpoint (SATTempHydHt-Sp)
  4. Hydronic Heat Valve % Command (HWV)

Operation

If the following conditions are true, the unit will enter SAT Tempering mode:

  • Supply Air Temperature < Hydronic Heat SAT Tempering Setpoint
  • Operational Occupancy is not unoccupied
  • Outdoor Air Damper is either in minimum position or doing free cooling

While SAT Tempering is active, Hydronic Heat Valve % Command is increased when supply air temperature is less than the setpoint and decreases if greater than the setpoint. If the unit is in free cooling mode, it will use the minimum of Hydronic Heat SAT Tempering Setpoint and VAV Operating Cooling Setpoint as the setpoint; else, it just uses Hydronic Heat SAT Tempering Setpoint.

The unit will exit SAT Tempering mode if any of the following conditions become true:

  • Supply Air Temperature >= Hydronic Heat SAT Tempering Setpoint and Hydronic Heat Valve % Command has been at 0% for three minutes
  • Operational Occupancy is unoccupied
  • Outdoor air damper no longer in minimum position or free cooling mode