If A Sensor Is Defective - Sanyo SAP–K181AHA–S Technical & Service Manual

9-5. If a sensor is defective.

9-5-1. Indoor coil temp. thermistor (TH1) is defective.
• Operation lamp on front side of
indoor unit is flashing on and off. (*)
NOTE Alarm Signal (*)
Operation lamp on the front side of the indoor unit will flash on and off when the indoor coil thermistor is defective.
At the same time the outdoor unit will stop. Indoor unit will operate only for ventilation.
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.
a) In Cooling mode: The air conditioner soon stops and will not start again.
b) In Heating mode: The air conditioner continues to operate (Thermo.ON). Both
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.
a) In Cooling mode: The air conditioner continues to operate (Thermo.ON). Both
b) In Heating mode: The air conditioner soon stops and will not start again
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.
YES
(Thermo.OFF) Neither outdoor fan nor compressor runs.
the outdoor fan and compressor do not stop. As a result, the
room becomes too warm.
the outdoor fan and compressor do not stop. As a result, the
room becomes too cold.
(Thermo.OFF). Neither outdoor fan nor compressor runs.
• Thermistor (TH1 ) is defective.
• Replace thermistor.
45
YES
Temperature
sensor
Lead
wires
Thermistor Structure