OUTDOOR
AIR
ENTHALPY
SENSOR
C7400
UNOCCUPIED
S6005
TIMER
OCCUPIED
Y1
Y2
W2
W1
G
RH
RC
T7300 OR T874
THERMOSTAT
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
2
MOTOR SPRING-RETURNS CLOSED WHEN FAN IS NOT RUNNING.
3
ASSURE THAT EQUIPMENT TRANSFORMER IS SIZED FOR THE EXTRA LOAD OF THE ECONOMIZER AND ACTUATOR.
4
1S IS AN ELECTRONIC SWITCH, WHICH CLOSES WHEN POWERED BY A 24 VAC INPUT.
5
RELAYS 1K AND 2K ACTUATE WHEN THE ENTHALPY SENSED BY THE C7400 IS HIGHER THAN THE ENTHALPY SETPOINT A-D.
6
FACTORY INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD BE REMOVED ONLY IF A C7400 ENTHALPY SENSOR
IS ADDED TO S R AND + FOR DIFFERENTIAL ENTHALPY.
Fig. 13. W7459A,D/C7400 used in two-stage cooling system with single enthalpy changeover and with M7415 Actuator.
TR
TR1
+
S O
S
S R
620 OHM
RESISTOR
1
3
T
C7150B MIXED
P
AIR OR
C7046A
DISCHARGE
AIR SENSOR
W
T6031 AMBIENT
LOCKOUT
R
CONTROL
50° F SETPOINT
SOLID STATE ECONOMIZER SYSTEM
W7459A ECONOMIZER PACKAGE
+
+
6
5
1K
5
2
1S
2K
4
4
T1
1S1
P1
MINIMUM POSITION
ADJUSTMENT
C
Y1
Y2
W2
W1
FDR
G
FDR
2
R
HVAC EQUIPMENT
TERMINAL STRIP
11
M7415 ACTUATOR
TR
24 VAC
TR1
T
MIXED
AIR
T1
SENSOR
P1
MINIMUM
P
POSITION
M7415
TR
COOL 1
24 VAC
TR1
COOL 2
SENSOR
T
T1
HEAT 2
P1
MIN
POS
P
HEAT 1
FAN
DELAY
RELAY
1
3
FAN
L2
L1
(HOT)
M10115
63-2484—1