Panasonic U-72MF1U9 Service Manual page 75

3. W-3WAY VRF Alarm Codes
F17 Alarm
Alarm code F17
Alarm meaning Low-pressure sensor (LPS) trouble
Alarm conditions (1) Sensor short circuit
(2) Sensor open circuit
Probable cause (1) Sensor malfunction (including connector)
(2) PCB malfunction
(1) Measure the sensor resistance. Check that the sensor is operating normally.
Check
(2) Use a remote monitor or a PC monitor to check the temperature that is recognized
by the microcomputer.
Correction —
—
Example
—
Notes
F31 Alarm
Alarm code F31
Alarm meaning Outdoor unit non-volatile memory (EEPROM) trouble
Alarm conditions (1) Non-volatile memory is not present when power initialization occurs.
(2) Read values do not match after writing to non-volatile memory is complete.
Probable cause (1) Memory was not inserted after the PCB was replaced.
(2) The lifetime of the non-volatile memory has been reached.
(3) Non-volatile memory is installed incorrectly (wrong direction, bent pins, etc.).
Check (1) Check the non-volatile memory on the PCB.
Correction —
—
Example
—
Notes
H03, H13 Alarm
Alarm code H03, H13
Alarm meaning H03: Compressor 1 CT sensor disconnected or short-circuit.
H13: Compressor 2 CT sensor disconnected or short-circuit.
Alarm conditions Compressor 1: Current value of more than 18.0 A is detected while the compressor 1 is stopped.
Compressor 2: Current value at compressor 2 is less than 2.0 A when 2 seconds or more had
* No current is detected even though the compressors are operating.
Probable cause (1) CT circuit failure (including cut wiring, etc.)
(2) Disconnected CT circuit connector
(3) Missing phase where CT circuit is connected.
(4) This CT circuit is connected to the connector of the other CT circuit.
(5) PCB failure
(6) Noise
Check (1) CT circuit failure, PCB failure
Trouble: • Current value during compressor operation is below the threshold value.
Check:
(2) Crossed wiring or installation error
Trouble:
(3) If the cause is still unknown after checking the above, then it is possible that noise is the
cause of the trouble. It is necessary to connect a PC or other instrument.
Correction (1) Replace the CT circuit.
(2) Replace the outdoor unit PCB.
(3) Correct the problem.
Example (1) The connector was not inserted after the PCB was replaced.
Use a normal CT as a tool to determine whether the trouble is a PCB failure or CT failure.
Notes
passed after the compressors began operation and output.
• Check that the connector is not disconnected.
• Check the continuity of the CT circuit.
• Install a normal CT in place of this CT and check. If current is detected, then the
PCB can be judged OK.
→
CT circuit failure
• Check that current is flowing in the phase where the CT circuit is connected.
→ Check voltage and current.
When the compressor is stopped, the current value at the other compressor is high.
* When this type of condition occurs, seizing-detection control takes priority.
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Trouble Diagnosis
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