Ventilation Control Processes; Fan System Start-Stop Control - Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual

VENTILATION CONTROL PROCESSES

The following applications show various ways of controlling ventilation in an air conditioning system.

FAN SYSTEM START-STOP CONTROL

FUNCTION AL DESCRIPTION
EA
RA
OA
Item
No.
1 Supply fan starts and enables return fan start
and system controls.
2 SA smoke detector stops supply fan when
smoke detected.
3 RA smoke detector stops supply fan when
smoke detected.
4 Controller stops fan when low temperature
detected.
5 SA high static pressure control stops fan when
unsafe pressure exists.
6 Automatic fan system control subject to
commandable ON-OFF-AUTO software point.
7 Control program turns supply, return, and
exhaust fan on and off dependent upon
optimized time schedule, unoccupied space
temperatures, and occupant override requests.
ENGINEERING MANUAL OF AUTOMATIC CONTROL
3
13
ON
RA
63
17
PERCENT
LOAD
4
NORMAL
PERCENT
LOAD
OA
TEMPERATURE
Function
AIR HANDLING SYSTEM CONTROL APPLICATIONS
PROPELLER
EXHAUST
FAN
ON
14
FAN SYSTEM
SCHEDULE AND
CONTROL PROGRAM
7
1
2
ON
SA
63
5
16
12
17
8 Occupant override switch provides after hours
operation when pressed.
9 Duration of operation for override request.
10 Space temperature (perimeter zone) inputs to
optimum start-stop, unoccupied purge, and
low limit programs.
11 Setpoint at which unoccupied low-limit
program executes.
12 OA temperature input to optimum start-stop
program.
13 Return fan operation enables exhaust fan
control program.
14 Exhaust fan status (operator information).
15 Warm-up mode status (operator information).
16 Supply fan load (VAV type systems-operator
information).
17 Return fan load (VAV type systems-operator
information).
209
SPACE
TEMPERATURE
10
23.5
11
OFF
16
SETPOINT STATUS
UNOCCUPIED
LOW LIMIT
AUTO
6
WARM-UP MODE
STATUS
OFF
15
UNOCCUPIED OVERRIDE
OFF 60
8
9
DURATION
STATUS
MINUTES
M15151