If A Sensor Is Defective - Sanyo SAP-K181A Technical & Service Manual

9-5. If a sensor is defective.

9-5-1. Indoor coil temp. thermistor (TH1) is defective.
A. Open
When thermistor opens, the air conditioner will be in the following conditions as the controller tries to detect
extremely low indoor coil temperature.
In Cooling mode: Function of freeze prevention continues to work. That is, the controller turns both
B. Short
When thermistor is short, the air conditioner will be in the following conditions as
the controller tries to detect extremely high indoor coil temperature.
In Cooling mode: Function of freeze prevention will not work even when the frost builds up on indoor heat
9-5-2. Room temp. thermistor (TH2) is defective.
A. Open
When thermistor opens, the air conditioner will be in the following conditions as the controller tries to detect
extremely low room temperature.
In Cooling mode:
B. Short
When thermistor is short, the air conditioner will be in the following conditions as
the controller tries to detect extremely high room temperature.
In Cooling mode:
NOTE
Definition of Open or Short Circuit of Sensor (Thermistor)
Open ... A lead wire is broken or disconnected or the circuit inside the temperature sensor is open .
Short ... The protective cover of a lead wire has been damaged, and the exposed wire is touching another metal
part, or both lead wires have become exposed and are touching each other. Alternatively, the circuit
inside the temperature sensor is closed.
compressor and outdoor fan motor periodically ON and OFF for several minutes.
(Refer to "8-3. Freeze Prevention")
exchanger coil
The air conditioner soon stops and will not start again. (Thermo.OFF) Neither outdoor fan
nor compressor runs.
The air conditioner continues to operate (Thermo.ON). Both
the outdoor fan and compressor do not stop. As a result, the
room becomes too cold.
36
Temperature
sensor
Lead
wires
Thermistor Structure