Proportional / hydronic heat - Johnson Controls - LIT-12011950 - Building automation software - Smart Equipment Controller - 5.0

Smart Equipment Controls Sequence of Operation Technical Bulletin

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

Setpoints and related data

The setpoints and related data include the following items:

  • Heating Control Type (Htg-Type) Proportional
  • Hydronic Heating Stage #1 Supply Air Setpoint (HydH1SA-Sp)
  • Hydronic Heating Stage #2 Supply Air Setpoint (HydH2SA-Sp)
  • VAV Supply Air Temp Reset Setpoint (SATRst-Sp)
  • Hydronic Heat Valve Reverse Acting (HydReverse)
  • VAV Operating Heating Setpoint (VAVOprHtg-Sp)
  • Hydronic Heat Valve % Command (HWV)

Operation

If the supply air temperature is lower than the VAV Operating Heating Setpoint, the Hydronic Heat Valve % Command modulates open. If the supply air temperature is greater than the VAV Operating Heating Setpoint, the Hydronic Heat Valve % Command modulates closed. The rate of change for Hydronic Heat Valve % Command is limited to 30% per minute.

The VAV Operating Heating Setpoint is determined using the VAV Supply Air Temp Reset Setpoint, Hydronic Heating Stage #1 Supply Air Setpoint, and Hydronic Heating Stage #1 Supply Air Setpoint. When the difference between the VAV Supply Air Temp Reset Setpoint and the Operational Space Temperature is less than or equal to 2°F, VAV Operating Heating Setpoint is equal to Hydronic Heating Stage #1 Supply Air Setpoint; otherwise VAV Operating Heating Setpoint is equal to Hydronic Heating Stage #2 Supply Air Setpoint.

Hydronic Heat Valve Reverse Acting allows support for either normally open or normally closed valves.