Johnson Controls CICM008B21S, Service Manual

Page: 110 / 152

5-12
SM-18003
EXTERNAL INPUT/OUTPUT AND FUNCTION SETTING
5.4.1.4 Control by Field-Supplied Room Thermostat
[ Input Setting: Code (01) (for Cooling), Code (02) (for Heating) ]
In a case where a field-supplied room thermostat is used instead of the inlet thermistor of the indoor unit in
order to run/stop the compressor, connect wires as shown below.
Operation
Cooling Operation: Compressor is ON by closing terminals 2 and 3 of CN3
Compressor is OFF by opening terminals 2 and 3 of CN3
Heating Operation: Compressor is ON by closing terminals 1 and 2 of CN3
Compressor is OFF by opening terminals 1 and 2 of CN3
2
Temperature
Increase
Thermostat
CN3
3
2
1
3
1
Indoor Unit PCB
3P Connector
Field-Supplied Room Thermostat
Example: Room Thermostat Input (for Cooling) is set to terminals 2 and 3 of CN3
Room Thermostat Input (for Heating) is set to terminals 1 and 2 of CN3
NOTE:
The contact capacity of a thermostat
shall be DC12V and several mA. Select a
thermostat which makes and breaks the
contact with this capacity.
( )
NOTE:
1. Make the wires CN3 as short as possible. Do not install the wires along the 220V power line. Install
them more than 12 in. (30cm) away from each other. (Intersecting them is acceptable.)
If the wires are installed along the power line, comply with the following points to prevent noise.
a. Pass either of the low voltage wire and 220V power line through a metal tube and ground one end.
b. Use a shielded wire for a low voltage wire and ground one end.
The maximum wiring length is 230 ft. (70m).
2. When using this function, it is recommended that safety devices such as an electric leakage breaker or
smoke detector, etc., be used because this is an unattended function.
3. For a thermostat, do not use a thermostat which uses mercury for a switch, because chattering is likely to
occur at ON/OFF.
4. Use a thermostat with a differential of 2
o
F (1.5
o
C) or more.
5. Comply with the following points. If not, a high-voltage circuit breaker will be activated or the unit will
repeat ON/OFF operation.
a. Install a thermostat where air inlet temperature can be detected correctly.
b. Install a thermostat where discharge air from the unit does not blow directly against it.
6. When using a room thermostat, set each room thermostat (for cooling and heating) correctly. If any of
them is set incorrectly, other room thermostats do not operate.