Panasonic U-72MF1U9 Service Manual page 95

1. Outdoor Unit Control PCB
Terminal plug
LED1, 2
D72, D75
Power LED
D53
Run
(CN103)
Stop
(CN104)
AP
(CN102)
Mode
(CN101)
Test
(CN022)
3P plug (black): For communications circuit impedance matching
• A connecting socket (3P, black) is attached to the terminal plug at the time of shipment from
the factory.
• In the case of link wiring which combines the inter-unit control wiring for multiple systems
into a single communications circuit, leave the connecting socket in place at only one of the
outdoor units, and move the socket from the "SHORT" side to the "OPEN" side at all other
outdoor units. If multiple connecting sockets are left in place, communications trouble will
occur.
LED (red × 2)
• LED 1 and 2 blink alternately while automatic address setting is in progress.
• Display the alarm contents for alarms which were detected by the outdoor unit.
LED (red): Power indicator
Indicates the DC 5V power on the outdoor unit control PCB.
2P plug (white): Start pin
Short-circuit this pin and apply a pulse signal to start all indoor units in that refrigerant system.
2P plug (white): Stop pin
Short-circuit this pin and apply a pulse signal to stop all indoor units in that refrigerant system.
2P plug (white): Vacuuming pin
• To perform vacuuming of the outdoor unit, short-circuit this pin and then turn the power ON.
All solenoid valves turn ON and vacuuming begins smoothly. (Do not perform automatic
address setting at this time.)
• Release the short-circuit to return the unit to normal status.
2P plug (white): Indoor unit Heating/Cooling mode change pin
• When operating the compressors to perform automatic address setting, operation in Heating
mode can be normally used. However, short-circuiting this pin performs operation in Cooling
mode. (Static signal)
• Short-circuiting this pin during ordinary operation changes the mode from Cooling to
Heating (if the current mode is Cooling) or from Heating to Cooling (if the current mode is
Heating).
2P plug (white)
• This pin is used to test the PCB at the factory.
• When the power is turned ON after this pin has been short-circuited, all output signals will
be output in sequence. (Sequential output does not occur if this pin is short-circuited when
the power is already ON.) Releasing this pin returns the unit to normal control.
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PCB and Functions
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