Multiple Coil Control From Outdoor And Supply Air - Honeywell AUTOMATIC CONTROL Engineering Manual

2
MA
1
OA 35°F DB, 29°F WB

MULTIPLE COIL CONTROL FROM OUTDOOR AND SUPPLY AIR

Functional Description
OA
TEMPERATURE
9 40
35
3
7
10
OPEN
OA
VALVE 2
PERCENT
OPEN TEMPERATURE
0
40
12
100
35
Item
No. Function
1,2 Control system energizes when fan is turned on
(See FAN SYSTEM START-STOP CONTROL).
3 OA damper opens when fan runs.
4-6 Supply air PID control loop modulates the coil #3
valve to maintain constant supply temperature.
7-9 Coil #1 is under open loop control by OA
temperature.
RA 75°F DB, 62.5°F WB
MA
PREHEAT AIR
70°F DB
C2553-1
VALVE 1
PERCENT
OPEN
0
CONTROL
PROGRAM
100
100
8
V1
N.O.
COIL
N.C.
NO. 1
COIL 1
AIR HANDLING SYSTEM CONTROL APPLICATIONS
The following results are obtained:
Item
No. Explanation
1 Heating of OA occurs along a line of constant
moisture content from 35°F to 70°F.
2 This condition represents the mixing of
preheated air and RA supplied to the system.
13
60 11
11
4
V2
N.O. N.O.
COIL
NO. 2
10
58
37
10-12 Coil #2 is under open loop control by coil #1
leaving air temperature.
13 Control program coordinates temperature,
ventilation, and fan interlock control.
14 Coil #2 leaving air temperature is for operator
information (unless alarm monitoring is desired).
231 ENGINEERING CMANUAL OF AUTOMATION CONTROL
64
SA
6
64
5
2
V3
NORMAL
1
COIL
ON
NO. 3
14
M10464