Panasonic U-4LE1E5 Service Manual page 92

3. Mini VRF System Alarm Codes
E04 Error in Indoor Unit Receiving Signal from the Outdoor unit
1. Error Detection Method
When there is no communication within a 3-minute period from the outdoor unit. Or, judged an error when no reply comes
from the outdoor unit.
• The outdoor unit is not turned on.
•
When the network of indoor/outdoor operation line was wired, the (SHORT) setting of the terminal resistor switch on the
outdoor control PC board was set on multiple units (four or more).
•
When the power was turned on after auto address setting was completed, the number of indoor units had been changed.
•
Forgot to turn on the indoor unit.
•
The CHK pin and/or TEST pin on the indoor unit's control PC board are shorted.
• Forgot to install the nonvolatile memory (EEPROM) when replacing the indoor unit control PC board.
•
Mistakenly set the indoor unit address to Not Set in the remote control's detailed setting mode.
•
When indoor unit addresses are duplicated.
• There is a short, open, wrong contact or grounding of the indoor/outdoor operation line.
• There is an error in the receiving circuit on the signal output PC board (optional control PC board).
•
Malfunctions of the outdoor unit
•
High voltage was applied (over AC200V) in the indoor/outdoor operations line circuit.
• The thermistor inside the indoor unit is grounded.
2. Error Diagnosis
1 Power
Source
1-1
1-2
2 Indoor/
2-1
outdoor
control line
2-2
2-3
3 No. of
5
3-1
Indoor
Units
3-2
3-3
4 Indoor
4-1
unit
control
PC board
4-2
4-3
4-4
4-5
4-6
4-7
Is/was the power to the outdoor unit cut off?
Is the indoor unit powered off?
Is the indoor/outdoor operation line shorted, opened, grounded
or has a wrong contact?
When the network of indoor/outdoor operation line was wired,
was the (SHORT) setting of the terminal resistor switch on the
outdoor control PC board set on multiple units (four or more)?
Was a high voltage (over AC200V) applied in the indoor/outdoor
operations line circuit?
Was the number of indoor units increased or decreased after
auto address setting was complete?
Conduct checks prior to auto address setting.
Check the indoor unit addresses from the remote control's
detailed settings mode.
Is it Not Set (99), or is the indoor unit's address duplicated?
Are the CHK pin and/or TEST pin on the indoor unit control PC
board short-circuited?
Is the wireless remote controller and/or optional control PC board
connected to on the indoor unit's control PC board?
Disconnect the connector mentioned above on the control PC board
of the indoor unit control PC board, and see whether the E04 goes off
after several minutes. (When doing so, if two remote controllers are
being used and the wireless remote controller is the main remote
controller, set the other remote controller as the main.)
Replace all optional control PC board and/or wireless remote control parts including wiring.
Is the LED on the indoor unit control PC board blinking?
The nonvolatile memory (EEPROM) on the indoor unit's control PC board is either not installed,
improperly installed or the nonvolatile memory is faulty. Correct this or after replacing the
nonvolatile memory, write model data to it in the remote control detailed settings mode.
Are all the remote controllers of the other indoor
units connected to that outdoor unit displaying E04?
Yes Replace the outdoor unit control board
No Replace the indoor unit control board
5 - 12
Mini VRF SYSTEM
Trouble Diagnosis
After turning the power
Yes
on, wait three minutes
No 1-2
Yes Power on
No 2-1
Yes Correct the wiring
No 2-2
Normally the (SHORT)
Yes
setting is just one unit.
No 2-3
Yes 3-2
No 3-1
Yes 3-2
No 3-3
Yes 3-2
No 4-1
Yes Remove the short
No 4-2
Yes 4-3
No 4-5
Yes 4-4
No 4-5
Yes 4-6
No 4-7