Honeywell AUTOMATIC CONTROL User Manual

PNEUMATIC CONTROL FUNDAMENTALS
93
ENGINEERING MANUAL OF AUTOMATIC CONTROL
Fig. 78. Heating Coil Control.
M
M
Y
2
EP
2
EP
M
Z
X
P
CX
O
P
CX
O
M
P
CX
O
P
CX
O
SR-1
SR-3
SR-2
RA
70
BSM
TC-1
2
EP
DA
90
BSM
TC-2
SA-1
C-X < 69
C-O >71
SNAP
ACTING
RELAY
RETURN
AIR
RETURN FAN
OUTSIDE
AIR
TO COOLING
CONTROLS
TS-1
FROM
COOLING
CONTROLS
3-8 PSI N.O.
SIGNAL TO OPEN
ALL INTERIOR VAV
BOX DAMPERS AND
START HOT WATER PUMP
M10301
TO
COOLING
CONTROLS
SUPPLY FAN
AIR DURING COLD RETURN AIR (WARM-UP)
MIXING DAMPER CONTROL SEQUENCE
Any time the AHU (Fig. 79) runs in the occupied mode
with Electric-Pneumatic Relay 1EP energized, Outside Air
airflow Controller P-F modulates the outside air damper toward
open and the return air damper toward closed (or vice versa)
in unison to maintain design outside air at 4000 cfm.
M
Y
Z
M
X
P
CX
O
SR-4
P
CX
O
SR-5
2
EP
DA
55°F
BSM
TC-3
L
BM
H
P-F
RA
OUTSIDE
AIR
2
EP
1
EP
TO WARM-UP
CONTROLS
TS-1
6-11 PSI
N.O.
4-11 PSI
N.O.
M
M
PE
B
RR
FROM WARM-UP
CONTROL
(AIR DURING
COLD RETURN)
M10302
SUPPLY FAN
P=O TO 20
B=20 TO 0
6-11 PSI CHW
OPEN TO CLOSED
AIR WHEN
FAN ON
TO HEATING COIL
CONTROL AND TO
CHILLER PLANT
CONTROL
3-8 PSI HW GOES OPEN TO CLOSED
9-14 PSI CHW GOES CLOSED TO OPEN
4-11 PSI
N.C.
PI
NOTE: These dampers can control in sequence also, but
unison control positions the damper blades better for
mixing which is helpful during freezing periods. If
the outside air is provided from an outside air shaft
with an outside air fan, an outside air filter is helpful
to keep the flow sensing element/pick-up clean and
effective. Electric-Pneumatic Relay 1EP starts the
outside air system.
Fig. 79. Mixing Damper and Discharge Air Temperature Control.

Honeywell AUTOMATIC CONTROL Specifications

General

Brand	Honeywell
Model	AUTOMATIC CONTROL
Category	Controller
Language	English