Multi Plus ODU Main Board Troubleshooting

Fault Code	Fault Description	Possible Reason for Fault	Potential Fixes
1	Outdoor Ambient Temperature Sensor Fault	The outdoor ambient temperature sensor connection is loose The outdoor ambient temperature sensor has failed The sampling circuit has failed	Reconnect the outdoor ambient temperature sensor Replace the outdoor ambient temperature sensor Replace the outdoor board
2	Outdoor Coil Temperature Sensor Fault	The outdoor coil temperature sensor connection is loose The outdoor coil temperature sensor has failed The sampling circuit has failed	Reconnect the outdoor coil temperature sensor Replace the outdoor coil temperature sensor Replace the outdoor board
3	The Unit Over-Current Turn Off Fault	Control board current sampling circuit has failed The current is too high because the supply voltage is too low The compressor is blocked Overload in heating mode Overload in cooling mode	Replace the control board Replace the compressor
4	EEprom Data Error	EE components have failed EE components control circuit failed EE components have been inserted incorrectly	Replace the EE components Replace the outdoor control board Reassemble the EE components
5	Cooling Freezing Protection (the indoor coil temperature is too low) or Heating Overload (indoor coil temperature is too high)	The indoor unit isn't blowing air normally The room temperature is too low in cooling mode or the room temperature is too high in heating Air filter is dirty The duct resistance is too high to result in low air flow The setting fan speed is too low The indoor unit is not standard installed, air inlet is too near with air outlet	Check the indoor fan, indoor fan motor and evaporator Clean the filter Check the volume control valve, duct length etc. Set the speed with high speed Reinstall the indoor unit refer to the user manual to change the distance between the indoor unit and the wall or ceiling.
7	Communication fault between the indoor unit and outdoor unit	The connection between the indoor unit and outdoor unit is poor The communication cable is loose The communication cable is faulty The indoor control board is faulty The outdoor control board is faulty Communication circuit fuse is open The specification of communication cable is incorrect	Reconnect the connection cable by referring to the wiring diagram Reconnect the communication cable Replace the communication cable Replace the indoor control board Replace the outdoor control board Check the communication circuit, adjust the DIP switch and the short-circuit fuse Choose suitable communication cable by referring to the user manual
13	Compressor overheat protector device	The wiring of the overload protector connection is loose The overload protector has failed Insufficient refrigerant The copper pipping is longer than normal, but no additional refrigerant has been added The expansion valve has failed The outdoor control board has failed	Reconnect the wiring of the overload protector Replace the overload protector Check for a refrigerant leak, fix it and re-add refrigerant If there is no leak, add refrigerant according to the length of the copper tubing. Replace expansion valve Replace the outdoor control board
14	The high pressure switch operates or the unit turns off for high pressure protection	The wiring of the high pressure protector connection is loose; The high pressure protector has failed The outdoor control board is abnormal Overload in cooling Overload in heating	Reconnect the high pressure protector Replace the high pressure protector Replace the outdoor control board Refer to "Overload in Cooling Mode addendum" Refer to "Overload in Heating Mode addendum"
15	Low pressure switch protection or the unit turned off for low pressure protection	The wiring of the low pressure switch is loose The low pressure switch has failed Insufficient amount of refrigerant Expansion valve failure in heating mode The outdoor control board is abnormal	Reconnect the wiring of the low pressure switch Replace the low pressure switch Check for a refrigerant leak, fix it and re-add refrigerant Replace the expansion valve; Replace the outdoor control board
16	Overload protection in cooling mode	System Overload	Refer to "Overload in Cooling Mode addendum"
17	Discharge temperature sensor fault	The wiring of the discharge temperature sensor connection is loose The discharge temperature sensor has failed The sampling circuit is abnormal	Reconnect the discharge temperature sensor Replace the discharge temperature sensor Replace the outdoor control board.
18	AC voltage is abnormal	The AC voltage > 275V or < 160V The AC voltage of sampling circuit on the driver board is abnormal	Please check the power supply Replace the driver board
19	Suction temperature sensor fault	The wiring of the suction temperature sensor connection is loose The suction temperature sensor has failed The sampling circuit is abnormal	Reconnect the suction temperature sensor Replace the suction temperature sensor Replace the outdoor control board
22	Defrosting sensor fault	The wiring of the defrosting sensor connection is loose The defrosting sensor has failed The sampling circuit is abnormal	Reconnect the defrosting sensor Replace the defrosting sensor Replace the outdoor control board
23	Expansion valve A tube (thin) sensor fault	The wiring of the sensor for the expansion valve A(thin tube) connection is loose The sensor for the expansion A(thin tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve A (thin tube) Replace the sensor for the expansion valve A (thin tube) Replace the outdoor control board
24	Expansion valve B tube (thin) sensor fault	The wiring of the sensor for the expansion valve B(thin tube) connection is loose The sensor for the expansion B(thin tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve B (thin tube) Replace the sensor for the expansion valve B (thin tube) Replace the outdoor control board
25	Expansion valve C tube (thin) sensor fault	The wiring of the sensor for the expansion valve C(thin tube) connection is loose The sensor for the expansion C(thin tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve C (thin tube) Replace the sensor for the expansion valve C (thin tube) Replace the outdoor control board
26	Expansion valve D tube (thin) sensor fault	The wiring of the sensor for the expansion valve D(thin tube) connection is loose The sensor for the expansion D(thin tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve D (thin tube) Replace the sensor for the expansion valve D (thin tube) Replace the outdoor control board
27	Expansion valve A tube (thick) sensor fault	The wiring of the sensor for the expansion valve A(thick tube) connection is loose The sensor for the expansion A(thick tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve A (thick tube) Replace the sensor for the expansion valve A (thick tube) Replace the outdoor control board
28	Expansion valve B tube (thick) sensor fault	The wiring of the sensor for the expansion valve B(thick tube) connection is loose The sensor for the expansion B(thick tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve B (thick tube) Replace the sensor for the expansion valve B (thick tube) Replace the outdoor control board
29	Expansion valve C tube (thick) sensor fault	The wiring of the sensor for the expansion valve C(thick tube) connection is loose The sensor for the expansion C(thick tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve C (thick tube) Replace the sensor for the expansion valve C (thick tube) Replace the outdoor control board
30	Expansion valve D tube (thick) sensor fault	The wiring of the sensor for the expansion valve D(thick tube) connection is loose The sensor for the expansion D(thick tube) has failed The sampling circuit is abnormal	Reconnect the sensor for the expansion valve D (thick tube) Replace the sensor for the expansion valve D (thick tube) Replace the outdoor control board
45	IPM fault	Please refer to "drive board fault codes" for more information	Please refer to "drive board fault codes" for more information
46	IPM and control board communication fault	The cable between the control board and the driver board is loose The cable between the control board and the driver board has failed The driver board has failed The control board has failed	Reconnect the cable between the control board and the driver board Replace the communication cable between the control board and the driver board Replace the driver board Replace the control board
47	Discharge temperature too high fault	Insufficient amount of refrigerant The refrigerant of the unit is not enough due to additional length of the installation pipe Throttling service has failed The outdoor ambient temperature is too high	Check for refrigerant leaks. Fix leak and re-add refrigerant Add refrigerant according to additional installation pipe length Replace the throttling service (such as capillary, expansion valve)
48	Outdoor DC fan motor fault (upper fan motor)	The wiring of the upper DC fan motor is loose The cord of the upper DC fan motor has failed The upper DC fan motor has failed The drive circuit of the upper DC fan motor has failed The outdoor fan has been blocked	Reconnect the wiring of the upper DC fan motor Replace the upper DC fan motor Replace the driver board of the fan motor Check the outdoor fan and ensure the outdoor fan can run normally
49	Outdoor DC fan motor fault (lower fan motor)	The wiring of the lower DC fan motor is loose The cord of the lower DC fan motor has failed The lower DC fan motor has failed The drive circuit of the lower DC fan motor has failed The outdoor fan has been blocked	Reconnect the wiring of the lower DC fan motor Replace the lower DC fan motor Replace the driver board of the fan motor Check the outdoor fan and ensure the outdoor fan can run normally
91	The unit turned off due to the IPM board over heating fault	The outdoor ambient temperature is too high The speed of the outdoor fan motor is too low The outdoor unit has been installed incorrectly The supply power is too low	Check the fan capacitor, and replace the fan capacitor if it has failed Reinstall the outdoor unit by referring to the installation user manual
96	The refrigerant of the unit is not enough fault	Insufficient amount of refrigerant	Check for leaks Charge refrigerant to recommended levels
97	4-way valve communication failure fault	The wiring of the 4-way valve coil is loose The 4-way valve coil has failed The 4-way valve has failed The driver board of the 4-way valve has failed	Reconnect the wiring of the 4-way valve Replace the 4-way valve coil Replace the 4-way valve Replace the driver board of the 4-way valve

Overload in Cooling Mode Addendum
Number	Cause	Corrective Measures
1	Too much refrigerant	Discharge refrigerant and refill to the appropriate level
2	The outdoor ambient temperature is too high	Please use within the rated ambient temperature range
3	The air outlet and the air inlet of the outdoor unit has short circuited	Adjust the installation according to the installation manual
4	The outdoor heat exchanger is dirty	Clean the heat exchanger of the outdoor unit
5	The speed of the outdoor fan motor is too low	Check the outdoor fan motor or fan capacitor
6	The outdoor fan is broken or the outdoor fan is blocked	Check the outdoor fan
7	The air inlet and outlet and been blocked	Remove the blockage
8	The expansion valve or the capillary has failed	Replace the expansion valve or the capillary

Overload in Heating Mode Addendum
Number	Cause	Corrective Measures
1	Too much refrigerant	Discharge refrigerant and refill to the appropriate level
2	The indoor ambient temperature is too high	Please use within the rated ambient temperature range
3	The air outlet and the air inlet of the indoor unit has short circuited	Adjust the installation according to the installation manual
4	The indoor filter is dirty	Clean the indoor filter
5	The speed of the indoor fan motor is too low	Check the indoor fan motor or fan capacitor
6	The indoor fan is broken or the outdoor fan is blocked	Check the indoor fan
7	The air inlet and outlet and been blocked	Remove the blockage
8	The expansion valve or the capillary has failed	Replace the expansion valve or the capillary

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