Panasonic CU-4KE24NBU, CU-4KE31NBU Checking the Outdoor System, Checking the outdoor unit

8-3. Checking the Outdoor System

8-3-1. Checking the outdoor unit

No.	Work procedure	Check items (unit operation)
1	• Apply 220 V AC between terminals L1 and L2 on the	• The LED (red) on the control board must illuminate.
	outdoor unit terminal plate.
2	• Short-circuit the T-RUN terminal to the COM terminal	• The compressor, fan motor, 4-way valve, and solenoid
	of TEST/T-RUN terminals.	valve (for the hot gas bypass) must turn ON.
		(They turn ON about (70) seconds later after the power
		is turned ON.)

NOTE If the above check items are okay, but the outdoor unit does not operate, there may be a faulty connection between the indoor unit and the outdoor unit.

8-3-2. Checking the defrost operation

Using forced defrost operation to check this function.

No.	Work procedure		Check items (unit operation)
1	• Connect a dummy resistor of 39 k ohm to the outdoor		Non-stop defrost
	coil temperature sensor connector.
						30 sec.
			Indoor fan
				Setting	LL		Stop			Setting
			CM					(80 Hz)
								ON
		Solenoid valve				5 sec.					10 sec.
			(for hot gas
			bypass) OFF					ON		OFF
			Outdoor fan
				ON				OFF		ON
				Defrost start					Release

• The maximum length of defrost operation is 12 minutes.

Defrost can also be released based on the below conditions for the outdoor heat exchanger sensor.

Less than 2 minutes Not released

2 minutes or more 57.2 °F or higher (*1)

*1 However, the condition is (68 °F) or higher when the outdoor air temperature is below 32 °F.

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