Honeywell AUTOMATIC CONTROL Engineering Manual page 430

INDIVIDUAL ROOM CONTROL APPLICATIONS
FAN
OA
46
OPEN
MINIMUM
CLOSED
OPEN/ON
CLOSED/OFF
On morning occupancy startup, the fan operates with the hot
water valve open, the face damper open, and the OA damper
closed; and as the room warms to a vent/recirculate setpoint,
the OA damper opens to a minimum ventilation position. As
the heating load drops, the face and bypass dampers modulate
to maintain the room heating temperature setpoint. As the room
temperature rises to a value midpoint between the heating and
cooling setpoints, the heating valve closes. If the room
temperature rises to the cooling setpoint, the OA damper
modulates to maintain the cooling setpoint.
ENGINEERING MANULA OF AUTOMATIC CONTROL
ON
55
00
PERCENT
OPEN
00
PERCENT OPEN
TO BYPASS
77
PERCENT OPEN
RA
TO OUTSIDE AIR
DISCHARGE HEATING
TEMPERATURE
SETPOINT PERCENT
55
105
HOT WATER VALVE
FAN ON
RECIRCULATE
SETPOINT
100
HEATING LOAD
PERCENT
FACE DAMPER
OA DAMPER
CLOSED
FAN ON
SETPOINT
UNOCCUPIED MODE
Fig. 28. Cycle II with Enhanced Digital Control.
WALL MODULE
TEMPERATURE
75
HEATING
73
SETPOINT
COOLING
75
SETPOINT
CONTROL
PROGRAM
24
DISCHARGE COOLING
LOAD TEMPERATURE
SETPOINT PERCENT
0
75
55
100
HEATING COOLING
SETPOINT SETPOINT
0 0
COOLING LOAD
PERCENT
OCCUPIED MODE
HOT WATER VALVE
FAN
CONVECTION
SETPOINT
Although the discharge air sensor could be used as a low
limit only, Figure 28 shows it as the primary controller reset
from the demands of the room sensor.
In the unoccupied mode, the valve is controlled in a two-
position manner to maintain an unoccupied convection heating
room temperature setpoint. If the room temperature cannot be
maintained by convection heating, the fan is cycled to maintain
the unoccupied heating fan-on setpoint. The face damper is
open and the OA damper is closed.
Figure 29 adds a chilled water coil to Figure 28.
420
MINIMUM
VENTILATION
DAMPER
SETPOINT
LOAD
0
100
100
M10547