INDOOR UNIT CONTROLS & COMPONENTS
PAGE 18
ENGLISH
Terminal Block 
Display
The indoor unit terminal block receives electrical power from 
the outdoor unit. There are 4 connections for electrical wires. 
Terminals 1 and 2 are connected to terminals 1 and 2 of the 
outdoor unit. This wiring supplies power to the indoor unit. 
Terminal 3 is a communication wire. The indoor unit sends 
indoor air temperature, coil temperature and temperature 
setpoint information to the outdoor unit on this wire. If a 
splice or break in this wire is present, the indoor unit will not 
be able to communicate with the outdoor unit. The ERROR 
CODE will be code E7.
The indoor display has an infrared communication circuit that 
receives operating commands from the remote control. This 
display will indicate operating modes, error codes, indoor air 
temperature, timer status and power status.
Ambient Temperature Sensor
The Room Ambient Temperature Sensor is a negative 
coecient thermistor that will decrease in resistance with 
increases in room air temperature. The sensor is located on a 
clip mounted to the surface of the indoor coil. 
The sensor connects to the control board at Plug CN-6.
Coil Temperature Sensor
The Coil Temperature Sensor is a negative coecient 
thermistor that will decrease in resistance with increases in 
coil temperature. The sensor is located in a socket soldered 
to the surface of the indoor coil. 
This sensor will monitor the temperature of the indoor coil 
in both cooling and heating modes of operation. Should 
abnormally cold or hot coil temperature be detected by this 
sensor, the system will take functional corrective steps to 
correct the condition or report an ERROR CODE. 
The sensor connects to the control board at Plug CN-6.