27
Note:
Only in heat pump air conditioner.
6.5 Over cooling or heating.
6.6 Sensor is defective
6.6.1 Temperature sensor of indoor heat exchanger is defective.
Definition of open or short circuit of sensor (thermal resistor):
Short circuit:
The protective cover of a lead wire has been damaged, and the exposed wire is
touching another metal parts. Or both lead wires have become exposed and are
touching each other. Or the circuit inside the temperature sensor is closed.
Open:
The lead wires are broken, or the circuit inside the temperature sensor is open.
7. Checking Electrical Components
7.1 Measure insulation resistance
The insulation is in good condition if the resistance exceeds 2 M
Ω
.
7.1.1 Power supply wires
Clamp the ground pins of the power plug with the lead clip of the
insulation resistance tester and measure the resistance by placing a
probe on either of the power wires. (Fig. 1)
Then measure the resistance between the
ground wire and the other power wire. (Fig. 1)
7.1.2 Indoor unit
Clamp an aluminum plate fin or copper tube with the lead clip of the
insulation resistance tester and measure the resistance by placing
a probe on each terminal screw on the terminal plate. (Fig. 2)
Note that the ground line terminal should be skipped for the check.
Check the set temperature.
The timer of indoor
unit is flash.
The sensor is
open or short.
Replace it.
