P04 Alarm; P05 Alarm - Panasonic U-8ME1E81 Service Manual

4. 3WAY Alarm Codes
4. 2WAY Alarm Codes

P04 Alarm

Alarm code P04
Alarm meaning High-pressure switch activated.
P04 Alarm
Alarm conditions 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
Alarm code P04
the terminal is short-circuited, it will remain in that state until the pressure goes below 3.15 MPa.
Alarm meaning High-pressure switch activated.
Probable cause (1) High-pressure switch failure or wiring connection failure
Alarm conditions The operation of the electronic circuit in the high-pressure switch may short-circuit the terminal
(2) Failure to open the service valve of the outdoor unit
depending on the pressure. A pressure of 3.3 MPa or above will short-circuit the terminal. Once
(3) Difference of characteristics of high-pressure sensor
the terminal is short-circuited, it will remain in that state until the pressure goes below 2.6 MPa.
(4) Clogging of the outdoor heat exchanger during cooling
(5) Air short circuit occurs during cooling.
Probable cause (1) Failure of the check valve in the compressor discharge tube.
(6)
Failure of the outdoor fan during cooling
(2) The service valve is closed.
(7) Clogging of the air filter in the indoor unit during heating
(3) Clogging of the outdoor heat exchanger during cooling.
(8) Air short circuit occurs during heating.
(4) An air short in the outdoor unit during cooling.
(9) Failure of the indoor fan during heating
(5) Failure of the outdoor fan during cooling.
(10) Clogging of the refrigerant circuit
(11) (6) Clogging of the air filter in the indoor unit during heating. Failure of the expansion valve
(12) Failure of the solenoid valve kit
(7) An air short in the indoor unit during heating.
(13) Too much refrigerant has been charged.
(8) Failure of the indoor fan during heating.
(14) The wiring from the solenoid valve kit is actually connected to the different indoor unit.
(9) Clogging of the refrigerant circuit.
(15) The system is that the multiple indoor units are connected at only one solenoid valve kit and also
(10) Failure of the mechanical valve.
multiple remote controllers are connected. "Installation of the common use solenoid valve kit"
(11) Failure of the solenoid valve kit. from a PC has not been made.
(12) Too much refrigerant has been charged.
Check (1) High-pressure switch failure or wiring connection failure
• Check under the section 6. "Inspection of Parts (1) High-pressure switch".
(13) Failure of the high-pressure switch.
• Check whether the socket of the high-pressure switch is surely inserted into the outdoor unit PCB.
Check (1) Make sure that the high-pressure switch connector has been properly connected.
(2) Failure to open the service valve of the outdoor unit.
(2) If the high-pressure switch is properly connected, connect a high-pressure gauge to the
• Check open/closed status of the outdoor unit service valve.
high-pressure outlet port and monitor the pressure during operation to check the pressure
(3) Difference of characteristics of high-pressure sensor
when the high-pressure switch is activated. Check valve failure is likely to occur if the pressure
•
Connect a gauge to the high-pressure outlet and check for changes in the value displayed by the
is less than 3.3 MPa. The following describes checks to be made when the pressure is high.
monitoring software, and for large deviation of the gauge pressure.
(3) During cooling, check whether the outdoor unit heat exchanger is clogged. Remove any
(4) During cooling, check whether the outdoor unit heat exchanger is clogged. Remove any foreign
foreign material that prevents ventilation.
material that prevents ventilation.
(5) During cooling, check whether an air short blockage has occurred in the outdoor unit. The system is
(4) During cooling, check whether an air short blockage has occurred in the outdoor unit. The
operating normally unless the temperature around the outdoor unit is excessively high.
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
(5) During cooling, check for outdoor fan failure. Check whether the screws securing the fan
and whether the fan connector in the outdoor unit PCB is properly connected.
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
(6) During heating, check whether the air filters in the indoor unit are clogged. If clogged, clean
filters.
the filters.
(8) During heating, check whether an air short blockage has occurred in the indoor unit. The system
(7) During heating, check whether an air short blockage has occurred in the indoor unit. The
operates normally unless the temperature around the indoor unit is excessively high.
(9) During heating, check for indoor fan failure. system operates normally unless the temperature around the indoor unit is excessively high.
(10) Check whether the refrigerant circuit is clogged. Check that all service valves are closed.
(8) During heating, check for indoor fan failure.
Check whether welded locations are clogged.
(9) Check whether the refrigerant circuit is clogged. Check that all service valves are closed.
(11) Check for expansion valve failure. Check whether the expansion valves make a clattering sound
Check whether welded locations are clogged.
when the power is reset. Since the expansion valve in the indoor unit is in a location that makes
(10) Check for mechanical valve failure. Check whether the mechanical valves make a clattering
aural inspection difficult, use an electric means to check. Check that the connector pin of the
sound when the power is reset. Since the mechanical valve in the indoor unit is in a location
expansion valve on the PCB outputs 4 V. In addition, check that the coil resistance of the
that makes aural inspection difficult, use an electric means to check. Check that the
expansion valve is several tens of Ohm (
(12) Check for solenoid valve kit failure. Removing a coil that is on will result in a clicking sound. connector pin of the mechanical valve on the PCB outputs 4 V. In addition, check that the
coil resistance of the mechanical valve is several tens of Ω.
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
(11) Check for solenoid valve kit failure. Removing a coil that is on will result in a clicking sound.
charged if the sub-cool temperature of the condenser is 15°C or more.
Also, removing a coil that is off will not produce such a sound.
(14) Check whether the wiring from the solenoid valve kit is actually connected to the different indoor
(12) Check whether too much refrigerant has been charged. Too much refrigerant has been
unit .
charged if the sub-cool temperature of the condenser is 15ºC or more.
(15) The system is that the multiple indoor units are connected at only one solenoid valve kit and also
Correction Replace damaged components and correct the amount of charged refrigerant.
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)
Example —
Correction Notes Replace damaged components and correct the amount of charged refrigerant. —

P05 Alarm

P05 Alarm
Alarm code P05
Alarm code P05
Alarm meaning Reverse phase (or missing phase) detected
Alarm meaning Reverse phase (or missing phase) detected
Alarm conditions This alarm occurs when a reverse phase or missing phase is detected in the L1-L2-L3-N phases.
Alarm conditions This alarm occurs when a reverse phase or missing phase is detected in the L1-L2-L3 phases.
Probable cause Reverse phase or missing phase in the L1-L2-L3-N phases
Probable cause Reverse phase or missing phase in the L1-L2-L3 phases
Check Check the wiring at the power terminal plate.
Check Check the wiring at the power terminal board.
Correction Switch the phases and reinsert. Check if the result is OK.
Correction Switch the phases and reinsert. Check if the result is OK.
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2WAY SYSTEM
3WAY SYSTEM
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