York J Series - Fig. 12 - Occupied Heating and Cooling Setpoint Selection Algorithm

FORM 100.50-NOM7 (808)
27
JOHNSON CONTROLS
3
Morning Warm Up
Morning Warm Up operation is carried out when:
• The Morning Warm Up parameter is ON.
• The Internal Clock/Schedule parameter is ON.
• Occupancy is scheduled for the current day.
The Morning Warm Up start time will be 60 minutes
prior to scheduled occupancy, or BAS initiates the
morning warm-up.
When started, the Morning Warm Up operation is as
follows:
• Close economizer.
• Turn the Supply Fan ON and operate for 5 minutes
before beginning temperature control.
• For stepped heating:
• Control to maintain the RAT to the Morning
Warm Up Setpoint using the algorithm illus-
trated in Figure 12.
• For Hydronic heating:
• The SAT is controlled to the 2
nd
Stage Hydronic
Heat Setpoint.
• The VAV Relay output of the controller is set to
10 VAC during heating.
Morning Warm Up operation will end when:
• An occupancy (space is occupied) input is received
from the controller input.
• The scheduled occupancy time occurs.
• The Morning Warm Up operation times out based
on the Max Morning Warm Up Time parameter.
• The transition from cooling to occupied heating
occurs at 2°F below the “VAV Setpoint for SAT
reset”.
• The reverse transition at 1.5°F below the “VAV
Setpoint for SAT reset”. There is no “satised” or
“idle” state of the unit between cooling and oc-
cupied heating.
FIG. 12 – OCCUPIED HEATING AND COOLING
SETPOINT SELECTION ALGORITHM
Enable VAV
Low Te mp.
Setpoint For
Cooling
Enable VAV
High Temp.
Setpoint For
Cooling
Enable VAV
Occupied
Hearing (If
Allowed)
-2.0˚F -1.5˚F
-0.5˚F
VAV Setpoint
For SAT Reset
+2.0F
SPA CE TEMPERA TURE
LD06561