Honeywell Design and Application Technical Reference Manual page 53

T7300 T7300
THERMOSTAT SUBBASE
RH
RC
X
C2
Y2
C1
Y1
H2
W2
H1
W1
FAN
G
COM
LED 1
LED 2
A1
AUX
A2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
1
OVERLOAD PROTECTION AS REQUIRED.
FACTORY-INSTALLED 620 OHM, 1 WATT, 5% RESISTOR
2
SHOULD BE REMOVED ONLY IF A C7400A SENSOR IS
ADDED TO SR AND + FOR DIFFERENTIAL ENTHALPY.
3 ENTHALPY CONTROL MAKES TERMINALS 2-1 ON
ENTHALPY RISE, AND 2-3 ON ENTHALPY FALL.
4 RELAY REQUIRED (R8222 OR SIMILAR).
T7300/Q7300 using W859D Economizer Package with H705A in two-stage
heating/two-stage cooling system, defeating economizer minimum position
OPTIONAL
H705A
C7400A
6
2
S
8
TYPICAL W859D ECONOMIZER CONTROL PACKAGE
MIXED AIR
MODUTROL®
TEMPERATURE
MOTOR
CONTROLLER
BLUE
W
B1
RISE
W1
R1
MINIMUM POSITION
T2
POTENTIOMETER
YELLOW
T1
W
4K1
1
L2
L1
4
(HOT)
during unoccupied periods
EXISTING HVAC EQUIPMENT
HVAC
EQUIPMENT
TERMINAL
TR1
TR
STRIP
SR
620
OHMS
3
2 1
3 3K
4
BLACK
OUTDOOR AIR
CHANGEOVER
7
SWITCH
R B
1K1 1K2
YELLOW
R B
OPEN
4K1
ECONIMIZER MOTOR SPRING RETURNS CLOSED ANY TIME
5
FAN IS NOT RUNNING.
6
FIELD INSTALLED JUMPER.
7 IMPORTANT: MIXED AIR SENSOR MUST BE LOCATED
DOWNSTREAM OF THE EVAPORATOR COIL IN THE DISCHARGE
AIR DUCT TO PROVIDE ECONOMIZER LOW LIMIT FUNCTION.
8
24 VAC ONLY.
9
MUST BE ABLE TO CARRY ADDITIONAL 6 VA LOAD OF
COMMERCIAL THERMOSTAT AND SUBBASE.
47
Section 4 - H705 Economizer Module
9
SYSTEM
TRANSFORMER
R
Y1
Y2
HEAT 1
W1
HEAT 2
W2
FAN
G
4 5
COOL1
COOL 2
W
R
2K1
B
2K2 T675 LOW
AMBIENT
COMPRESSOR
LOCKOUT
2K
1K
VIOLET
VIOLET
Honeywell Economizers 63-8594-02
L1 L2
(HOT)
M12167B