Panasonic CU-4KS31NBU Branch tubing temperature sensor, Breaker, Refrigerant gas pressure

(7) Branch tubing temperature sensor

Check that the sensor is securely contained in the thermostat holder.

(8) Breaker

Check whether or not the breaker has been tripped.

Check that the breakers and fuses used are of the specified capacity.

Check that the breaker and its line are exclusive for A/C use.

(9) Refrigerant gas pressure

Start a COOL test run, and messure the temperatures of the A/C intake air and discharge air. Compare the values with the performance charts.

If the values are higher than the performance charts:

Check for refrigerant shortage or blockage of the refrigerant circuit.

<Assessment of refrigerant shortage >

1.The pressure in the low-pressure section is 5 MPa or more below the value in the performance charts.

2.There is little condensation on the indoor heart exchanger, which overall appears dry.

<Distinguishing between refrigerant shortage and refrigerant circuit blockage >

If the pressure in the low-pressure section does not change when the circuit is charged 2 to 3 times with refrigerant gas (0.44 lbs each time), or if the change is small, then the problem may not be refrigerant shortage.

The problem may be a blockage of the refrigerant circuit.

1.Check that there is no internal leakage inside the 4-way valve:

At the low-pressure side tubing, check that there is no temperature difference between the intake and discharge of the 4-way valve.

2.Check that the electric expansion valve is not blocked. Check as described on the preceding page.

77