Other Functions - Panasonic U-10MF1E8 Service Manual

19. Other Functions

19-1. Snowfall Sensor Functions: Outdoor EEPROM 04
A unit identified as having a snowfall sensor attached will periodically send a signal indicating the snowfall sensor
input status to all outdoor units in the same system (or all wired outdoor units in the case of linked systems). It is
therefore unnecessary to install and wire multiple snowfall sensors.
(1) Snowfall sensor settings
Setting
1
0 Sensor input not present. Control is performed. (Setting at time of factory shipment)
1 Sensor input present. Control is performed.
2 Sensor input not present. Control is not performed.
3 Sensor input present. Control is not performed.
* If the snowfall sensor is used, then depending on the circumstances it is necessary to make the correct setting at
all outdoor units in the system.
* If "control is not performed" is set, control by the above signal is ignored. This setting is used in order to conserve
energy at outdoor units that include a snowfall-protection hood.
Recommended: If a low-speed fan mode is required (for all-year cooling or other reasons), install a snowfall-
protection hood and set this setting to ON.
(2) Control operation
[1] Outdoor units where "sensor input present" is set send the snowfall sensor input information every 10
minutes to all linked systems if the system wiring is linked.
[2] At systems where "control is performed" is set, the above information is used to control operation of the
outdoor fan.
[3] At systems where "control is not performed" is set, the snowfall sensor input and above information ignored,
and the outdoor fan does not operate.
[4] In the case of a 3-WAY SYSTEM, control can be performed when snowfall sensor input is connected to any
outdoor unit.
<Caution>
Snowfall sensor input information is detected once every 10 minutes. Therefore, the outdoor fan may continue
operating for up to 10 minutes even when there is no snowfall sensor input.
In addition, the outdoor fan may remain stopped for up to 10 minutes when snowfall sensor input is present.
19-2. Function for Automatic Judgment of Insufficient Refrigerant Gas and Overcharge
This system includes a simple function for judging the level of refrigerant. However, be aware that false judgments
may occur if the control elements of the outdoor unit or indoor unit fail.
(1) Starting refrigerant level judgment mode
Short-circuit the CHECK pin on the No. 1 outdoor for 4 seconds or longer to engage this mode. (The LED on
the outdoor unit PCB begins blinking.)
(2) Conditions for refrigerant level judgment
After judgment mode starts, judgment occurs when all outdoor units in the system have been operating
continuously for 30 minutes or longer.
* Refrigerant level judgment requires that all outdoor units operate continuously for 30 minutes or longer. This is
in order to prevent incorrect adjustment of the refrigerant level based on false detection caused by refrigerant
accumulation or recovery at stopped outdoor units (stopped due to failures of functional elements). After
the judgment is displayed, repeated judgment will occur under new operating conditions if all outdoor units
continue operating. Therefore, the judgment display may change when later judgments occur.
* Judgment mode is automatically canceled after 4 hours.
Operation
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3-WAY SYSTEM
Control Functions