Panasonic U-72MF2U9 Service Manual page 177

4. 2WAY Alarm Codes
3. 3WAY Alarm Codes
H03, H13 Alarm
Alarm code H03, H13
Alarm meaning H03 : Current sensor for the 1st compressor is disconnected or shorted.
H13 : Current sensor for the 2nd compressor is disconnected or shorted.
1st compressor, 2nd compressor When the frequency of compressor is over 35Hz and the secondary
Alarm conditions
* 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) This CT circuit is connected to the connector of the other CT circuit.
(4) The Outdoor Unit Control PCB failure
(5) Electrical noise
Check (1) CT circuit failure, the Outdoor Unit Control PCB failure
Trouble: • Current value during compressor operation is below the threshold value.
Check:
(2) Crossed wiring or installation error
Trouble: When the compressor is stopped, the current value at the other compressor is high.
(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 Control PCB.
(3) Correct the problem.
Example (1) The connector was not inserted after the PCB was replaced.
Notes Use a normal CT as a tool to determine whether the trouble is a PCB failure or CT failure.
H05, H15 Alarm
Alarm code H05, H15
Alarm meaning H05 : DISCH1 thermistor at the discharge of 1st compressor is disconnected, shorted or misplaced.
H15 : DISCH2 thermistor at the discharge of 2nd compressor is disconnected, shorted or misplaced.
Alarm conditions • This alarm occurs when the discharge sensor temperature detector is not inserted into the tube's
sensor holder, or when the sensor itself has suffered some kind of malfunction other than a cut
wire.
• When outdoor air temperature is 14°F (-10°C) or higher:
Alarm occurs if the temperature detected by the discharge sensor has changed by less than
3.6°F (2°C) when the compressor has operated for 10 minutes immediately after start.
• When outdoor air temperature is below 14°F (-10°C):
Alarm occurs if the temperature detected by the discharge sensor has changed by less than
3.6°F (2°C) when the compressor has operated for 30 minutes immediately after start.
Probable cause (1) Discharge sensor temperature detector is not inserted into the tube's sensor holder.
(2) Discharge sensor itself has suffered some kind of malfunction other than a cut wire.
Check (1) Check that the discharge temperature sensor is inserted into the sensor holder.
(2) Check that sufficient heat-conducting putty is applied.
(3) Remove the discharge sensor from the sensor holder and expose the sensor to the outside
air for approximately 5 minutes. Check that the temperature detected by the sensor changes
to match the outside air temperature. (However the sensor cannot detect temperatures at or
below 32°F (0 °C).)
Correction (1) Install the sensor into the holder, and apply sufficient heat-conducting putty.
(2) If the sensor is malfunctioning, replace it.
Example
current is over 7.0A, the primary current detected lower than 0.7A.
• 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
Outdoor Unit Control 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 this type of condition occurs, seizing-detection control takes priority.
(DISCH1)
(DISCH2)
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2WAY SYSTEM
3WAY VRF SYSTEM
Trouble Diagnosis
Trouble Diagnosis
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