Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual page 426

INDIVIDUAL ROOM CONTROL APPLICATIONS
FAN
OA
8
OPEN
MINIMUM
CLOSED
OPEN/ON
CLOSED/OFF
On mor ning occupanc y star tup, the fan oper ates with the hot
water v alve open, the f ace damper open, and the O A damper
closed; and as the r oom war ms to a v ent/r ecircula te setpoint,
the O A damper opens to a minim um ventila tion position. As
the hea ting load dr ops, the face and b ypass damper s modula te
to maintain the r oom hea ting temper atur e setpoint. As the r oom
temper atur e rises to a value midpoint betw een the hea ting and
cooling setpoints, the hea ting v alve closes. If the r oom
temper atur e r ises to the cooling setpoint, the O A damper
modulates to maintain the cooling setpoint.
ON
13
00
PERCENT
OPEN
00
PERCENT OPEN
TO BYPASS
77
PERCENT OPEN
RA
TO OUTSIDE AIR
DISCHARGE
TEMPERATURE
SETPOINT PERCENT
13
41
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
24
HEATING
22.5
SETPOINT
COOLING
22.5
SETPOINT
CONTROL
PROGRAM
24
HEATING DISCHARGE COOLING
LOAD TEMPERATURE
SETPOINT PERCENT
0
24
13
100
HEATING COOLING
SETPOINT SETPOINT
0 0
COOLING LOAD
PERCENT
OCCUPIED MODE
HOT WATER VALVE
FAN
CONVECTION
SETPOINT
Although the disc har ge air sensor could be used as a lo w
limit onl y, Figur e 28 shows it as the pr imar y contr oller r eset
from the demands of the r oom sensor .
In the unoccupied mode , the v alve is contr olled in a tw o-
position manner to maintain an unoccupied con
room temperature setpoint. If the room temperature cannot be
maintained b y convection hea ting, the fan is cycled to maintain
the unoccupied hea ting f an-on setpoint. The face damper is
open and the O A damper is c losed.
Figur e 29 ad ds a c hilled water coil to F igur e 28.
ENGINEERING MANUAL OF AUTOMATIC CONTROL
416
MINIMUM
VENTILATION
DAMPER
SETPOINT
LOAD
0
100
100
M15315
vection hea ting