Multizone Unit - Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual

AIR HANDLING SYSTEM CONTROL APPLICATIONS

MULTIZONE UNIT

Functional Description
THE ZONE WITH THE GREATEST HEATING DEMAND
RESETS THE HOT DECK TEMPERATURE FROM
13 TO
MAINTAIN ITS SPACE TEMPERATURE
1.0
DEGREES BELOW SETPOINT.
THE ZONE WITH THE GREATEST COOLING DEMAND
RESETS THE COLD DECK TEMPERATURE FROM
26
TO
MAINTAIN ITS SPACE TEMPERATURE
1.0 DEGREES ABOVE SETPOINT.
22
PERCENT
OPEN
OA MINIMUM SETPOINT
(NOTE: THE TEST AND
BALANCE INITIAL
VALUE FOR PROPER
VENTILATION IS 22)
Item
No. Function
1,2 Control system energizes when fan is turned
on (See FAN SYSTEM START-STOP
CONTROL).
3,4 Mixing dampers position to minimum
position during occupied fan operation and
modulate for cooling.
5-8 Zone mixing dampers modulate to maintain
space temperature setpoint.
9 Zone with greatest cooling demand
determines cold deck temperature setpoint,
and zone with greatest heating demand
determines hot deck temperature setpoint.
36 DEGREES AS REQUIRED TO
15
DEGREES AS REQUIRED TO
78
RA
3
OA
ECONOMIZER DECISION.
REFER TO PREVIOUS
ECONOMIZER OPTIONS
14
4
22
6
46
62
100
PERCENT
OPEN TO
COLD
DECK
00
10
2
NORMAL
ON
1
25 15
00
12
16
CONTROL
PROGRAM
10,11 Hot deck valve modulated to maintain hot
deck temperature setpoint.
12,13 Cold deck valve modulated to maintain cold
deck temperature setpoint.
14 Economizer enables free cooling when OA is
suitable.
15 Fan leaving air temperature for operator
information.
16 Control program coordinates cooling, heating,
ventilation, and fan interlock control.
ENGINEERING MANUAL OF AUTOMATIC CONTROL
250
5 7
23.5 23.5
HALL
LOBBY
23.5 23.5
EAST
OFFICE
WEST
23.5 24.5
OFFICE
SPACE
SETPOINT
TEMPERATURE
11
25
8
SA
14
13
M15178