Panasonic CU-3KE19NBU, CU-4KE31NBU, CU-4KE24NBU service manual Explanation of Functions

7. FUNCTIONS

7-1. Explanation of Functions

NOTE The numerical values such as temperature, frequency, time and current in parentheses are an example

of CU-4KE31NBU and the values are different from the other models.

	Control/conditions		Unit operation	Explanation
INITIAL Breaker is ON.				Power is supplied to the indoor and outdoor unit
				control circuits, however the unit remains stopped.
				Positioning of the outdoor unit electric expansion
				valve is performed.
	The ON/OFF operation	If automatic operation mode has been selected		This applies in the case of automatic
	button on the remote	with the remote controller, operation begins in		HEAT/COOL operation.
	controller is pressed.	HEAT, SENSOR DRY, or COOL mode
		depending on the room temperature and
		outdoor temperature at the time operation starts.

			Depending on the operational mode, refer to the HEAT, SENSOR DRY, or COOL item.
HEAT	The ON/OFF operation		Operation lamp illuminates.	The unit is forced to stop for 3 minutes after
	button on the remote		Indoor fan is stopped to prevent cold air from	the power is turned ON, or 3 minutes after the
	controller is pressed.			compressor stops, in order to protect the
			being emitted.
				compressor.
			Outdoor unit begins operating after
				The frequency is increased at the rate of 1 Hz
			forced-stop is canceled.
				every 0.5 seconds.
			When the indoor coil temperature rises,	Depending on the relationship between the
			the compressor starts,	remote controller temperature setting and the
				room temperature, the compressor may stop
			the outdoor fan starts,
				temporarily (in other words, the thermostat
			and the indoor fan changes from "LL"
				may turn OFF).
			to the set fan speed.
		When the frequency reaches Hz,frequency		This is in order to stabilize the return of oil to the
		increases are stopped for a period of seconds.		compressor.
		(Refor to Table 2 "Freguency control".)
		The frequency then increases.		If the indoor and outdoor temperatures are high,
				the current peak cut-off activates, stopping any
				increases in frequency.
	The room temperature		The indoor temperature and the remote	Operating frequency is stabilized in order to
	has reached the desired		controller temperature setting are	maintain a comfortable environment.
	temperature.		approximately equal.
	The thermostat turns		The indoor fan is stopped.	The outdoor unit stops. (It does not stop if the
	OFF.			thermostat for another indoor unit is ON.)
				Approximately 30 seconds after the
				thermostat turns OFF, the indoor fan is
				stopped.
	The indoor and outdoor	In order to protect the compressor, the outdoor		The outdoor unit starts automatically after 3
	temperatures are high.	unit will not operate for 3 minutes after the		minutes.
		thermostat turns OFF, even if the room		During these 3 minutes, a low-pressure
		temperature drops below the desired
				pressure balance is achieved, allowing the
		temperature.
				compressor to start more easily.
			The frequency is not increased, even if	The amount of heat pump exceeds the amount
			there is a difference between the room	of heat radiation from the room.
			temperature and the desired temperature.	Therefore, there is no need to further increase
			In some cases, the frequency may be	the compressor capacity, and the frequency is
			decreased.	stabilized or lowered.

71