13. Servicing Mode

13.1 Pump Down Operation

Operate the pump down according to the following procedures.

1Confirm the valve on the liquid side and gas side is open.

2Press PUMP DOWN switch (SW1) on the display printed circuit board for more than 5 seconds. Pump down (cooling) operation is performed for 15 minutes.

3Set the liquid side 3 way valve to close position and wait until the pressure gauge indicates 1.45 PSI.

4Immediately set the gas side valve to close position and then press the PUMP DOWN switch (SW1) to stop the pump down operation.

Note: Pump down operation will stop automatically after 15 minutes if PUMP DOWN switch (SW1) is not pressed again.

Pump down operation cannot be restarted until 3 minutes after compressor is stopped.

LED

2

3

4

5

Message

 

 

 

 

 

 

 

Pump down operation progress

Status

 

3 minutes before operation end

 

 

2 minutes before operation end

 

 

 

1 minute before operation end

 

 

 

 

 

 

 

 

 

Pump down operation end

 

 

 

 

 

 

: Flashing

13.2 Test Operation

Test operation can be carried out using OPERATION TEST switch (SW2) on the display printed circuit board inside the outdoor unit. For cooling test, press the TEST OPERATION switch (SW2) for more than 5 seconds. LED 1 and LED 2 will illuminate when shift into cooling test operation.

13.3 Wiring Error Check

This product capable to correcting the wiring errors automatically by following procedures.

1Confirm the valve on the liquid side and gas side is open.

2Press WIRING CHECK switch (SW3) on the display printed circuit board for more than 10 seconds to start wiring check operation.

3Wiring check process will complete in approximately 10 minutes. However, wiring check operation will not start within 3 minutes after compressor is stopped. When outdoor air temperature is less than 41°F or unit has

abnormality, wiring check will not start. (See NOTE 2).

The LED 2 to 6 in display printed circuit board inside the outdoor unit indicate whether correction is possible or not and the status of the correction, as shown in the table below.

LED

2

 

3

 

4

 

5

 

6

Message

 

 

 

 

 

 

 

 

 

 

 

ROOM

A

 

B

 

-

 

-

 

-

 

 

 

 

 

 

 

 

 

 

 

 

 

All flashing

 

Automatic correction impossible

 

 

 

Status

LED 2, 4, 6 and LED 3,

Wiring check in progress

5 alternatively flashing

 

Flashing one after

Automatic correction completed

 

 

 

another

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Other than above

 

Unit has abnormally (Note 4)

 

 

 

 

 

 

 

 

 

 

 

If automatic correct is impossible, check the indoor unit wiring and piping manually.

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Panasonic CU-2S18NBU-1 service manual Servicing Mode, Pump Down Operation, Test Operation, Wiring Error Check