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4. W-2WAY ECO-i Alarm Codes
F04, F05 Alarm
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| Alarm code | F04, F05 |
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| Alarm meaning | Compressor 1 discharge temperature sensor trouble, compressor 2 discharge temperature | |
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| sensor trouble. |
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| Alarm conditions | (1) Discharge temp. of 212°F or higher was detected 20 minutes or more after that compressor | |
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| stopped operating. |
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| (2) Discharge temp. of 158°F or higher was detected after all compressors had been stopped for | |
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| 60 minutes or longer. |
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| (3) A/D step is 10 steps or less (short circuit). | |
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| Probable cause | (1) Sensor malfunction |
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| • Sensor element malfunction |
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| • Sensor wiring is partially disconnected, resulting in increased electrical resistance. | |
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| This alarm does not occur when the wiring is cut or when the connector is not connected to | |
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| the outdoor unit PCB. |
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| (2) Crossed wiring or installation error | |
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| • The discharge temperature sensor of that compressor is connected to the discharge tube | |
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| of the other compressor. |
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| • The connector for the discharge temperature sensor of the problem compressor is | |
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| connected to the outdoor unit PCB connector for the other compressor. | |
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| (3) Outdoor unit PCB failure |
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| (4) The check valve on the discharge tube for that compressor is wet. | |
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| (5) An air short blockage in the area around the outdoor unit has increased the outdoor unit | |
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| ambient temperature, reducing the cooling effects after the compressor stops. | |
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| (6) There is a cause that results in P03, P17, or P02 alarm. | |
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| (7) Electrical noise |
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| Check | (1) Sensor malfunction and outdoor unit PCB failure | |
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| Trouble: • Constantly indicates a high temperature. | |
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| • When monitoring software or other means are used for monitoring, the discharge | |
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| temperature at times fluctuates suddenly and wildly. | |
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| • In some cases, the precise temperature may not be known, even when monitoring | |
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| software is used. |
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| Check: • Wiggle the sensor and check whether the trouble continues. | |
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| • Check whether the connector is partially disconnected from the PCB. | |
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| An F04 alarm will not result if the connector is completely disconnected (circuit is | |
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| open). |
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| • If the cause is still uncertain, check the following to determine whether a sensor or | |
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| PCB failure has occurred. | |
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| Step 1: Connect the other compressor discharge sensor, or a discharge sensor where | |
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| the F04 alarm has not occurred, to the connector for this compressor on the | |
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| PCB. Measure the temperature at the same point (a location where temperature | ||
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| fluctuations are small), and check whether there is a temperature difference. | |
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| Difference ¡ | A PCB or sensor failure is possible. |
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| No difference ¡ PCB and sensor are normal. | |
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| Step 2: If an abnormality was found at Step 1, connect the problem compressor | |
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| sensor to the other compressor connector on the PCB, or to the PCB | |
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| connector of a device where the F04 alarm has not occurred. Measure the | |
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| temperature at the same point (a location where temperature fluctuations are | |
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| small), and check whether there is a temperature difference. | |
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| Difference ¡ | Sensor failure. |
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| No difference ¡ PCB failure. | |
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| It is convenient at this time to have a discharge temperature sensor on hand. | |
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| (2) Crossed wiring or installation error | |
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| Trouble: Although the other compressor is operating and this compressor is stopped, the | |
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| discharge temperature of the other compressor does not increase and the discharge | |
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| temperature of this compressor rises. | |
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| * The discharge temperature remains high immediately after the compressor stops. Wait | |
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| for some time after the compressor stops and observe. | |
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| Check: Check for crossed wiring and installation errors. | |
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| Continued |
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