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9 68-0173—3
WIRING DIAGRAMS
W8900A,C Hookup Diagrams
Fig. 11. Hookup diagram for heating/cooling system in conventional system with multiple transformers.
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
JUMPER R TO RH FOR SINGLE HEAT TRANSFORMER APPLICATIONS.
CONFIGURE PC8900 FOR HUMIDITY CONTROL IN HEATING MODE
(HUMIDIFIER) OR COOLING MODE (DEHUMIDIFIER) DURING INSTALLER SETUP .
W8900 ALLOWS CONNECTION OF A CO MONITOR WITH UNCOMMITTED CONTACTS.
SEE VENTILATION INSTRUCTIONS FOR WIRING.
GROUNDING THE GND TERMINAL IS NOT RECOMMENDED.
CONNECTION FOR CM8900A REMOTE COMMUNICATIONS MODULE.
S1
S
T1
T
OUT
OUT
LED
G
Y2
Y1
W1
W2
1
2
3
4
GND
C
R
RH
RC
HUM
HUM
VNT
VNT
W8900A,C
L1
(HOT)
L1
(HOT)
L2
L2
1
2
4
1
1
3
2
3
4
5
5
STAGE 1
HEAT RELAY
STAGE 2
HEAT RELAY
STAGE 1
COOL RELAY
STAGE 2
COOL RELAY
FAN RELAY
PC8900
1
2
3
4
CO
2
MONITOR
M4479D
HEATING
TRANSFORMER
COOLING
TRANSFORMER
HUMIDIFIER
OR DEHUMIDIFIER
EQUIPMENT
VENTILATION
EQUIPMENT
CO
2
C7189A REMOTE AIR
TEMPERATURE SENSOR
C7100 DISCHARGE AIR
TEMPERATURE SENSOR
C7089A OUTDOOR AIR
TEMPERATURE SENSOR
6
7
6
7
2