69-0895—1
3
C7189A WALL MOUNT TEMPERATURE SENSOR
M4456
W8900
C7189
C7189
W8900
C7189
C7189
C7189
C7189
C7189
C7189
C7189
C7189
C7189
C7189
C7189
4
1
2
3
2
3
4
4
SENSORS MUST BE ARRANGED IN THIS NUMBER AND CONFIGURATION FOR PROPER OPERATION.
S1
S
LED
L1
(HOT)
L2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
IF MORE THAN ONE C7189 REMOTE SENSOR IS REQUIRED, REFER TO FIGURE BELOW.
IF SHIELDED CABLE IS REQUIRED, GROUND TO GND TERMINAL ON W8900.
GND
C
R
RH
RC
C7189
W8900
S1
S
S1
S
Fig. 2. Wiring Diagram for the C7189 Sensor to the W8900 Remote Module.
OPERATION
The C7189 Wall Mount Temperature Sensor converts
room temperature to a resistance that the controller can
interpret. The C7189 has a negative temperature coeffi-
cient (NTC), which means that the resistance decreases
as the temperature increases. Fig. 3 shows how sensor
resistance decreases by 19 ohms per degree Fahrenheit.
The C7189 can be used to control as one remote sensor,
as a temperature averaging network with the PC8900, or
with multiple C7189 Sensors connected as shown in Fig. 2.
