Name: Manual for U-8MF2E8
Brand: Panasonic
Availability: InStock

Troubleshooting and error codes

Alarm code	Alarm meaning	Alarm conditions	Probable cause	Check	Correction	Example
H08, H27 Alarm
H08, H27	Trouble (open circuit) with the oil sensor (connection) at compressor 1 and compressor 2	This alarm occurs when a connector connection (pins 1 and 2 for compressor 1, pins 4 and 5 for compressor 2) is open.	Disconnected connector	Check that the connector is securely connected.	(1) Connect the connector. (2) Correct the connection at connector pins 4 and 5.
H31 Alarm
H31	HIC trouble alarm	This alarm occurs when the microcomputer identifies a trouble signal (indicating abnormal HIC temperature or other trouble) from the HIC. The HIC judges the current and temperature, and outputs the trouble signal. In general this indicates trouble with the HIC itself.	Overcurrent in HIC circuit, and the resultant abnormal heating, caused by HIC failure	Check the power wiring and connector wiring. If the wiring and connectors are normal, use a tester to measure the resistance between the compressor HIC power (HIC+) and ground (HIC-). If there is a short-circuit, there is an HIC malfunction.	If an HIC failure is found, replace the PCB.	Turn OFF the power, and check the continuity of HIC+ and HIC– on the HIC PCB.
L04 Alarm
L04	Outdoor system address duplication	Communication by inter-unit control wiring was received that contained the same address as that unit 5 times or more within 3 minutes.	Incorrect outdoor system address settings	Check the system address settings again.	Correct the system address settings.	Recovery from this alarm occurs automatically (when communication that contains the same address as that unit is not received for 3 minutes after detection).
L10 Alarm
L10	Outdoor unit capacity not set	The outdoor unit capacity has not been set, or the setting is not allowed by the system. This alarm occurs because the capacity has not been set.		Connect the outdoor unit maintenance remote controller. On the outdoor unit EEPROM detailed setting mode screen, check the value for the outdoor unit capacity (item code 81). Check that it is not set to "0" or to a capacity that is not allowed.	If item code 81 is incorrect, use the outdoor unit maintenance remote controller and set it correctly. After changing the setting, be sure to reset both the indoor and outdoor power.	The outdoor unit maintenance remote controller is required in order to set the capacity in the outdoor unit EEPROM.
L11 Alarm
L11	Installation or connection failure in a common use solenoid valve kit, miswiring of indoor unit's remote control group	(1) The connection system with the multiple indoor units at only one solenoid valve kit and installation failure of "common use solenoid valve kit" * "L11" alarm occurs in the same series of all remote controllers. (2) The connection system with the multiple indoor units at only one solenoid valve kit and wire connection that is not allowed * "L11" alarm occurs at the only target indoor unit. (3) Remote control group wiring with a different refrigerant circuit's indoor unit * "L11" alarm occurs at the only target indoor unit.	(1) Installation failure of "common use solenoid valve kit" (setting from PC at test run operation) and address setting is not made in the same series of all indoor units. (2) Wiring shown below that are not allowed ① Remote control group wiring with a different solenoid valve kit connected to the indoor unit ② Remote control group wiring more than one (1) indoor unit with type E1 within only one solenoid valve kit ③ Remote control group wiring with a different refrigerant circuit in the indoor unit	(1) When setting "installation of common use solenoid valve kit" is made by PC, check whether the installation change was made in the same series of all indoor units or not. (Check the software of address setting of PC.) * In this case, "L11" alarm occurs at all indoor units' remote controllers. (2) Check the condition of remote control group wiring where "L11" alarm occurs. Check whether the group wiring is made with the indoor unit of a different solenoid valve kit or not. Check whether the group wiring is made with the indoor unit of a different refrigerant circuit or not. (3) Check the model of indoor unit connected to a remote control group where "L11" alarm occurs. Check whether type E1 indoor units are connected in the group wiring or not. * Check the model of indoor unit with the item code 10 for the detailed setting of the remote control.	(1) Perform "installation of common use solenoid valve kit" from PC in the same series of all indoor units. (2) With a common use solenoid valve kit, change into the wiring that is allowed.	This alarm may occasionally occur when connecting the common use solenoid valve kit.
L17 Alarm
L17	Outdoor unit model mismatch	This alarm occurs when a unit other than R410A refrigerant model is connected.	(1) A unit that uses R407C refrigerant, or a R22 model unit, was connected by mistake. (2) The connected unit is correct, however the refrigerant type setting in the outdoor unit EEPROM (item code 80) is incorrect.	(1) Check the refrigerant type at the connected unit. (2) Use the outdoor unit maintenance remote controller and check the item code 80 refrigerant type. If the setting is incorrect, change it to R410A.	The outdoor unit's maintenance remote controller is required in order to set the refrigerant type in the outdoor unit EEPROM.
P02 Alarm
P02	Compressor thermal protector is activated. (trip only and no alarm)	When the current is not detected over 4 seconds long after the compressor ON.	Activating condition of the compressor thermal protector (The voltage is more than 260V or less than 160V between L and N phase.)	(1) Check the constant speed compressor. (2) Check the current transformer.	• Put the constant speed compressor OFF over 60 minutes and cool the thermostat. • Replace defective parts with new ones.
P03, P17 Alarm
P03, P17	Compressor 1 discharge temperature trouble Compressor 2 discharge temperature trouble	Compressor 1: Pre-trip stops when the temperature exceeds 106°C. Compressor 2: Pre-trip stops when the temperature exceeds 106°C. * The alarm occurs when pre-trip stop occurs more than once. However the pre-trip counter is cleared if the compressor operates continuously for a specified length of time (more than 2.5 minuites).	(1) Malfunction of expansion valve (MOV4) (2) Insufficient amount of refrigerant (including trouble resulting from an insufficient initial charge and from gas leakage) (3) Blocking of low-pressure parts caused by intrusion of foreign objects (moisture, scale, etc.) (4) Crossing (tubing or PCB connectors) with the other compressor thermistor (5) Malfunction of expansion valves (MOV1, MOV2) (6) Refrigerant is accumulated into the stopped outdoor units. (7) Compressor discharge sensor failure (8) Outdoor unit PCB failure (9) Failure to open the service valve of the outdoor unit (10) Electrical noise	(1) Malfunction of expansion valve (MOV4) Trouble: Although the expansion valve (MOV4) opens (MOV4 does not indicate "0" on the monitoring software), the discharge temperature of the said compressor does not decrease. Check: Check whether the MOV4 secondary side refrigerant tube is cold when the expansion valve (MOV4) opens. (2) Insufficient refrigerant Trouble: Liquid effectiveness is poor. Check: Check whether or not the superheating temperature is declining if the expansion valve is opened to 300 pulses or more (after checking for foreign object intrusion). (3) Foreign object intrusion Trouble: Liquid valve effectiveness is poor. Check: Check that there is no difference in the condensation or frost conditions between the strainer primary-side and secondary-side tubing. (4) Crossed thermistor Trouble: The discharge temperature of the other compressor is high although only this compressor is operating. When the liquid valve turns ON, the discharge temperature of the other compressor decreases. (5) Refrigerant is accumulated into the stopped outdoor units. Trouble: System is OK when all outdoor units are operating, however symptoms of insufficient gas occur when a certain outdoor unit is stopped. Condensation or frost is visible up to the top of the accumulator of the stopped outdoor unit. After an outdoor unit stops, there is the sound of refrigerant flowing into an outdoor unit that was stopped for a long time. • When an outdoor unit starts after being stopped for a long time, the start is accompanied by much vibration. Check the following points limited to the stopped outdoor units (while the other outdoor units are operating). • Refrigerant leak on the expansion valves (MOV1, MOV2, MOV4) • The expansion valve of the outdoor units stopped are all closed without any sound. The sound of refrigerant flow can be heard when refrigerant leaks. • Close the liquid service valve (normally "open") and check whether the sound of refrigerant flow can be heard. When the sound stops, refrigerant leaks. If refrigerant leaks from the expansion valve (MOV4), the temperature of the secondary refrigerant tube becomes lower than the outdoor temperature. Refrigerant leaks from the expansion valve (MOV2) and check valve connected in apposition (check valves for 14 & 16HP only) • When the outdoor units stoppped, there is no refrigerant flow normally. But once refrigerant leaks, the sound of refrigerant flowing from the check valve can be heard. • Close the liquid tube service valve (normally "open") and check whether the sound of refrigerant flow from the check valve stops. When the sound stops, refrigerant leaks. (6) Sensor failure Check: • This alarm is likely to occur when wiring is partially cut. (It is difficult to identify, even when continuity is checked.) The detected discharge temperature is high. Although such conditions rarely occur, a P02 alarm is likely if the detected discharge temperature is low. • Replace the sensor with another discharge sensor and compare the temperature conditions. (7) Failure to open the service valve of the outdoor unit Check open/closed status of the outdoor unit service valve. (8) If the cause is still unknown after checking the above, there is possibility that electrical noise is the cause of the trouble.	(1) Replace the sensor. (2) Replace the outdoor unit PCB. (3) Correct the problem locations.	All of the probable causes
P04 Alarm
P04	High-pressure switch activated.	The operation of the electronic circuit in the high-pressure switch may short-circuit the terminal depending on the pressure. A pressure of 3.8 MPa or above will short-circuit the terminal. Once the terminal is short-circuited, it will remain in that state until the pressure goes below 3.15 MPa.	(1) High-pressure switch failure or wiring connection failure (2) Failure to open the service valve of the outdoor unit (3) Difference of characteristics of high-pressure sensor (4) Clogging of the outdoor heat exchanger during cooling (5) Air short circuit occurs during cooling. (6) Failure of the outdoor fan during cooling (7) Clogging of the air filter in the indoor unit during heating (8) Air short circuit occurs during heating. (9) Failure of the indoor fan during heating (10) Clogging of the refrigerant circuit (11) Failure of the expansion valve (12) Failure of the solenoid valve kit (13) Too much refrigerant has been charged. (14) The wiring from the solenoid valve kit is actually connected to the different indoor unit. (15) The system is that the multiple indoor units are connected at only one solenoid valve kit and also multiple remote controllers are connected. "Installation of the common use solenoid valve kit" from a PC has not been made.	(1) High-pressure switch failure or wiring connection failure Check under the section 6. "Inspection of Parts (1) High-pressure switch". Check whether the socket of the high-pressure switch is surely inserted into the outdoor unit PCB. (2) Failure to open the service valve of the outdoor unit. Check open/closed status of the outdoor unit service valve. (3) Difference of characteristics of high-pressure sensor Connect a gauge to the high-pressure outlet and check for changes in the value dispalyed by the monitoring software, and for large deviation of the gauge pressure. (4) During cooling, check whether the outdoor unit heat exchanger is clogged. Remove any foreign material that prevents ventilation. (5) During cooling, check whether an air short blockage has occurred in the outdoor unit. The system is operating normally unless the temperature around the outdoor unit is excessively high. (6) During cooling, check for outdoor fan failure. Check whether the screws securing the fan are loose and whether the fan connector in the outdoor unit PCB is properly connected. (7) During heating, check whether the air filters in the indoor unit are clogged. If clogged, clean the filters. (8) During heating, check whether an air short blockage has occurred in the indoor unit. The system operates normally unless the temperature around the indoor unit is excessively high. (9) During heating, check for indoor fan failure. (10) Check whether the refrigerant circuit is clogged. Check that all service valves are closed. Check whether welded locations are clogged. (11) Check for expansion valve failure. Check whether the expansion valves make a clattering sound when the power is reset. Since the expansion valve in the indoor unit is in a location that makes aural inspection difficult, use an electric means to check. Check that the connector pin of the expansion valve on the PCB outputs 4 V. In addition, check that the coil resistance of the expansion valve is several tens of Ohm (Ω). (12) Check for solenoid valve kit failure. Removing a coil that is on will result in a clicking sound. Also, removing a coil that is off will not produce such a sound. (13) Check whether too much refrigerant has been charged. Too much refrigerant has been charged if the sub-cool temperature of the condenser is 15°C or more. (14) Check whether the wiring from the solenoid valve kit is actually connected to the different indoor unit. (15) The system is that the multiple indoor units are connected at only one solenoid valve kit and also multiple remote controllers are connected. Check whether "installation of the common use solenoid valve kit" from a PC has been made. (Confirmation from the address setting software of a PC)	Replace damaged components and correct the amount of charged refrigerant.
P05 Alarm
P05	Reverse phase (or missing phase) detected	This alarm occurs when a reverse phase or missing phase is detected in the L1-L2-L3 phases.	Reverse phase or missing phase in the L1-L2-L3 phases	Check the wiring at the power terminal board.	Switch the phases and reinsert. Check if the result is OK.
P14 Alarm
P14	O2 sensor operation	(1) It is judged an error whenever the outdoor unit receives the signal "O2 Alarm Generated" from the indoor unit. (2) With the indoor unit's EEPROM setting (item code OB) set to 0001, the EXCT input was shorted.	(1) System configuration 1-1 Is an O2 sensor being used? (2) Indoor EEPROM setting 2-1 Is the EEPROM setting, item code OB, on the indoor control board set to 0001? (3) EXCT wiring 3-1 Is the EXCT socket (wire) shorted? (4) Indoor control board 4-1 Is the alarm triggered if the EXCT socket (wire) is disconnected, and the power is reset?	If "Yes", see "3-1". If "No", see "2-1". If "Yes", see "3-1" after modification. If "No", see "4-1". If "Yes", Modify the wiring. If "No", see "4-1".	4-2 Since there is no error, see what happens. 4-3 Indoor control board defective → replace board
P16 Alarm
P16	Compressor 1 (INV) overcurrent alarm	This alarm occurs when current trouble or current detection trouble occur (when trouble judgement current is detected in the secondary current). * Changed to output error by current regardless of the inverter frequency. When more than the current values shown in the table are instantly detected in the secondary current.	There is a strong possibility of a compressor failure. An alarm occurs for current detection trouble when it is judged that no current is flowing after start (DCCT is damaged). In this case, the cause is a DCCT failure.	Check the power wiring and connector wiring.	It is possible to resolve this trouble by limiting the maximum frequency.
P22 Alarm
P22	Fan motor trouble	Fan motor start failure, fan motor Hall IC input failure Possible causes are a Hall IC input circuit failure and a fan HIC failure.	Check the fan motor wiring, the Hall IC wiring, and the connector connections. If the wiring and connectors are normal, then check that the capacitor of the Hall IC input circuit is securely soldered on the outdoor unit control PCB. Also use a tester and measure the resistance between fan HIC power (HIC+) and ground (HIC-). If there is a short-circuit, there is an HIC malfunction.	If the fan does not start, the below corrections may be effective. (1) If there is a fan HIC failure or circuit failure, replace the PCB. (2) If the fan motor is locked, replace the fan motor.	Turn OFF the power, and check the continuity of "+" and "–" on the fan circuit PCB.
P29 Alarm
P29	Inverter compressor missing phase or lock alarm	This alarm may occur at start, and occurs when missing phase or lock is detected, and when a DCCT failure occurs.	Generally this alarm occurs when the refrigerant pressure balance is uneven at start, or when inverter compressor lock occurs, there is a missing phase in the inverter compressor wiring, or a DCCT failure occurs. This can be judged to be starting trouble which is not caused by HIC.	Check the power wiring and connector wiring.	DCCT failure (replace PCB) or compressor failure	Use a tester to measure the voltage between the DCCT output terminal on the rear of the PCB and the ground. If the voltage is not within 2 – 3 V, then the DCCT has malfunctioned.

Manual for U-8MF2E8

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Troubleshooting and error codes