Mitsubishi Air Conditioner Error Codes



Mitsubishi Electric Fault Code Check List Index:

Mitsubishi Air Conditioning Error Codes
Mitsubishi Air Conditioning Error Codes – How to Fix?
  1. Mitsubishi Mr Slim P Series (A) Error Codes
  2. Mitsubishi Mr Slim P Series (K) Error Codes
  3. Mitsubishi Multi City VRF Error Codes
  4. Mitsubishi inverter Cassette AC Error Codes
  5. Mitsubishi Ecodan Error Codes
  6. Mitsubishi PWFY Series Error Codes
  7. Mitsubishi CAHV Error Codes
  8. Operation Light Flashing
  9. Troubleshooting

1- Mitsubishi Electric Mr Slim P Series (A) Error Codes

Mr. Slim P-Series ductless heat pumps and air conditioners are compact yet powerful, offering unrivaled energy efficiency and design flexibility. Their advanced technology has been designed and tested to withstand the extremes of the Canadian climate in order to deliver a reliable and proven climate control system that you can trust all year round. With a variety of models to choose from, there’s a P-Series solution for any commercial application.

Mitsubishi Mr. Slim Air Conditioner Error Codes
Mitsubishi Mr. Slim Air Conditioner Error Codes – Meaning and Solution
Fault CodesProblem
A0 Duplicate address - Lossnay units attached with the same address - change addresses and reset the units power
A2Hardware error of transmission processor (Lossnay) - check comms wiring, and for possible Lossnay board fault
A3Line busy no data could be transmitted for 8 minutes - check A- M-Net connections (TB7 and TB3)
A6Communication error with communication processor - Lossnay address not transmitted - check M-Net voltage
A7No ACK signal - check A- M-Net wiring, range of transmission wiring exceeded or if faulty A- M-Net converter
A8M-Net no response - check A- M-Net wiring, range of transmission wiring exceeded, faulty A- M-Net converter or if incorrect wire used for M-Net connection
EAMis-wiring/loose inter-connecting cables. Noise interference
EBMis-wiring/loose interconnecting cables. Noise interference. Wrong cable size/spec
ECStart-up time over. The unit has failed to initialise after power up. Noise interference. Wrong cable size/spec
EDSerial communication error. Comms error between boards on outdoor unit caused by M-Net interface board incorrectly fitted
EFNon-defined error code. Noise interference - power down outdoor unit for 30 seconds then switch back on
E0Remote controller communication error - check wiring, connections and comms voltage. Also check Master/Slave settings if multiple systems are connected
E1Remote controller issue - if grouped, check addressing. If twinned, check wired to master indoor only
E2Remote controller issue - if grouped, check addressing. If twinned, check wired to master indoor only
E3Remote controller issue - not transmitting - if grouped, check addressing. If twinned check wired to master indoor only
E4Remote controller issue - not receiving - if grouped, check addressing. If twinned, check wired to master indoor only
E5Remote controller issue - not receiving - if grouped, check addressing. If twinned, check wired to master indoor only
E6Indoor/outdoor communication error, mainly caused by outdoor unit being powered up before indoor unit. Drain pump being wired into S1 and S2 causes interference
E7Comms fault between I/C and O/C - check for condensate pump at I/C, reset power to O/C, check 12/24Vdc on S2 and S3 possible I/C board failure
E8Comms failure indoor to outdoor (S2/S3) - check pumps wired in, check indoor isolator and re-power in the correct sequence i.e. indoor then outdoor
E9Comms failure indoor to outdoor (S2/S3) - check pumps wired in, check indoor isolator and re-power in correct sequence i.e. indoor then outdoor
FA51CM connector open - check thermal relay for disconnection or contact failure. Possible defective board
F1Reverse phase detection - check power supply, try swapping 2 phases round. Possible defective board
F2L3 phase open - check power supply, also check for open circuit protection devices
F363L open - check low pressure switch for disconnection or contact failure. Possible defective board
F449C open - compressor inner thermostat for open circuit or contact failure
F563H open - check high pressure switch for disconnection or contact failure. Possible defective board
F7Phase detection circuit fault - faulty outdoor board
F8No input detected at outdoor unit - outdoor board defective
F9Two or more protection devices are open - check protection devices for disconnection or contact failure
P1Return air thermistor fault (TH1) - check if TH1 disconnected or open or close circuit
P2Liquid pipe thermistor fault (TH2) check if TH2 disconnected or open or close circuit
P4Drain sensor fault - DS open or close circuit
P5High condensate level - drain pump failure or blockage in the drain
P6Freezing/Overheating of indoor unit heat exchanger - mainly caused by reduced air flow through indoor coil. Dirty filters. Fan motor problem. Blockage
P8Abnormal pipe temperature - mainly caused by refrigerant leakage. Possibility that the thermistor mounted incorrectly
P9TH5 condenser/evaporator thermistor open/close circuit. Disconnected from the board
U1High pressure trip - outdoor fan failure, blocked coil, blockage in the system, blocked filters on indoor in heating etc
U2High discharge temperature - compressor over heating due to lack of refrigerant, faulty thermistor, high ambient running conditions. Can also be caused by 49C (comp inner thermostat or external Klixon ) tripping
U3Discharge thermistor fault
U4Outdoor thermistor fault
U5Inverter heat sink temperature too high (TH8) - check for lack of air flow around heat sink, no silicone paste, faulty thermistor (temperature can be read from service tool (or PAR21 on power inverter model))
U6Compressor over current - carry out inverter output test and electrical checks to the compressor
U7Low discharge superheat - check TH4 reading is correct. Check LEV operations
ho-For about 2 minustes following power-on, operation of the remote controller is not possible deu to system start-up. - Connector for the outdoor unit's protection device is not connected. -Reserve or open phase wiring for the outdoor unit's power terminal block (L1,L2,L3). -Incorrect wiring between indoor and outdoor units (incorrect polarity of S1,S2,S3). -Remote controller wire short.
FFFFNo unit. Buzzer sound: Triple beep. Operation Led: No lit.
U0-UPOutdoor unit error.
F1-FAOutdoor unit error.
E0-E5Signal error between remote controller and indoor units.
E6-EFCommunication error between indoor and outdoor units.
--No alarm history.

2- Mitsubishi Electric Mr Slim P Series (K) Error Codes




Mitsubishi Electric Fault Codes
Mitsubishi Electric Fault Codes – Solutions

Mr. Slim P-Series is the ductless solution for demanding environments that require an efficient and reliable heating or cooling system. P-Series ductless systems are stylish, compact, and more attractive than traditional systems. Advanced technology also means your Mr. Slim ductless system will run more efficiently than a conventional unit, saving you from rising energy costs.

Fault CodesProblem
EOSystem transmission error - check for possible comms fault between I/C and R/C, could also be incorrect group or master/slave settings (check CN40, SW2 and SW6)
P1TH1 fault - check return air thermistor (6.4K_ @ 20°C)
P2TH2 fault - check coil/pipe thermistor (6.4K_ @20°C)
P3System transmission error - check for possible comms fault between I/C and R/C, could also be incorrect group or master/slave settings (check CN40, SW2 and SW6)
P4Drain sensor fault - check drain sensor resistance, connection and continuity
P5Drain fault - unit has detected high condensate - check for blockage in drain or tray, pump failure or sensor fault
P6Frost protection in cooling/Overheat protection in heating - detected by indoor coil sensor - general causes are lack of air flow or refrigerant charge problem
P7System error - address setting fault - check CN40 SW2 and SW6. Potential board issue
P8Abnormal pipe/coil temperature - no temperature change at indoor unit after 9 minutes of operation. General causes are outdoor unit tripped, problem with refrigerant charge or lack of air flow at the indoor unit. TH2 faulty or not mounted correctly
LD1Reverse phase on mains supply - change phases around, check for potential board problem
LD2Component open circuit - check CH, 52C, 21S4, SV, 63H and 26C for open circuit or disconnected
LD3Outdoor coil thermister is open or short circuit may be disconnected or outdoor board fault
LD463H high pressure switch open - investigate high pressure causes, 63H switch disconnected
LD551CM overcurrent relay open - compressor locked or pulling too much current - check power supply
LD626C thermal switch open - check if refrigerant level low or if 26C is disconnected
LD7Overheat protection - coil temp has exceeded 67°C - reduced airflow through condenser - check for fan motor problem or thermistor problem
LD8Input circuit of outdoor board - replace the outdoor board

3- Mitsubishi Multi City VRF AC Error Codes

The CITY MULTI S series (for small applications) and Y series (for large applications) make use of a two-pipe refrigerant system, which allows for system changeover from cooling to heating, ensuring that a constant indoor climate is maintained in all zones.

Mitsubishi Multi City VRF AC Error Codes
Mitsubishi Multi City VRF AC Error Codes – How to Fix It?



Error CodesProblem
403Comms fault between boards - check inverter error detail for which 2 boards, check transformer, bus voltage and inter-connecting cables
900Lossnay unit in test run
1102High compressor discharge temperature. Discharge temperature has exceeded 110°C or more. Short of refrigerant. Discharge thermistor
1111Low pressure/temperature fault - check thermistors (TH2, TH3, TH4), gas charge, indoor fan, heat exchanger and filter
1112Low pressure/temperature fault - check thermistors (TH2, TH3, TH4), gas charge, indoor fan, heat exchanger and filter
1113Low pressure/temperature fault - check thermistors (TH2, TH3, TH4), gas charge, indoor fan, heat exchanger and filter
1202Preliminary fault to 1102
1204Preliminary heat exchanger gas temperature sensor fault - check thermistors 10a and 10b
1205Preliminary thermistor fault (TH5)
1211Preliminary thermistor fault (TH2)
1214Preliminary thermistor fault (THHS)
1216Preliminary thermistor fault (TH7)
1217Preliminary thermistor fault (TH8)
1219Preliminary thermistor fault (TH9)
1221Preliminary thermistor fault (TH6)
1243Preliminary thermistor fault (TH10)
1301Low pressure fault (63L operation) low pressure sensor sensing less than 1 bar immediately before starting
1302High pressure fault - check pressure in system for more than 29 bar (R407c) 38 bar (R410A). Check high pressure sensor against gauge pressure
1368Pressure sensor fault (PS1) at BC - compare pressure reading on SW1 on O/C
1370Pressure sensor fault (PS3) at BC - compare pressure reading on SW1 at O/C
1402Preliminary fault to 1302
1500System overcharge. Abnormal low compressor superheat - discharge thermistor TH4
1501High compressor shell temp - check for shortage of gas, insufficient indoor index running (comms room units)
1505Suction pressure abnormal - generated by low pressure sensor detecting a vacuum - check for blockage, closed valve or sensor fault
2500Detecting lack of water flow on a water circuit
2502I/C has water level in drip tray, when the unit was running in cooling (temperature sensors - check for open or closed circuit and operation of pump)
2503I/C has water level in drip tray when the unit was running in cooling (float sensor - check for closed circuit on float switch and operation of pump)
2600Water leak from humidifier
4100Compressor over current protection on Mr Slim with M-net interface - check inverter or compressor
4101Compressor over current protection on Mr Slim with M-net interface - check inverter or compressor
4102Open phase fault - check power supply and noise filter for loss of phase, check wiring and fuses
4103Reverse phase fault - check phase rotation, loss of phase through the noise filter, fuse blown and high pressure switch open at power on
4106Transmission power supply fault - check wiring, high current, incorrect voltage on transmission line and/or M-Net board
4108Over current protection on DOL compressor - check power supply, contactor and compressor
4115Power supply abnormal - check power, fuses, connections and PCB
4116Fan motor abnormal - check fan motor and board (relates to indoor unit or Lossnay unit)
4124Thermal switch (49C) open circuit on Mr Slim on M-Net - reset and check pressures and air flow
4210Compressor over current problem - check inverter balance. Compressor and inverter
4220Low inverter board BUS voltage. Less than 289VdcDC is detected. - check mains supply
4225 Low DC voltage on Vdc on fan inverter - check CNVdc for 300Vdc on diode stack and check mains power supply to outdoor unit
4230High temperature on heat sink on inverter - check for blockages in air duct, failure of INV fan or failure of thermistor
4235Fan inverter heat sink overheat protection. Reduced airflow through heat sink. Fan motor problem. THHS thermistor problem
4240Over current protection. If high current is detected for more than 10 minutes - check inverter balance. Reduced airflow through heat sink
4245Over current protection. Possible ACCT current sensor fault. Should read 280 ohms between pins 1 & 2 and across pins 3 & 4
4250Over current protection. Inverter IPM problem. Compressor lock - check inverter balance
4255Inverter cooling fan problem - if high static fan is used then check that SW3-9 is on
4260Preliminary inverter heat sink overheat protection. Reduced airflow through heat sink. Fan motor problem. THHS thermistor problem
5101Thermistor fault at indoor/outdoor unit - check fault code address
5102Thermistor fault at indoor/outdoor unit - check fault code address
5103Thermistor fault at indoor/outdoor unit - check fault code address
5104Thermistor fault at indoor/outdoor unit - check fault code address (indoor fault - check SW7-3 is off)
5105TH5 open/short circuit - check if the TH is disconnected from the board
5106TH6 open/short circuit - check if the TH is disconnected from the board
5107TH7 open/short circuit - check if the TH is disconnected from the board
5108TH8 open/short circuit - check if the TH is disconnected from the board
5109TH9 open/short circuit - check if the TH is disconnected from the board
5110TH10 open/short circuit - check if the TH is disconnected from the board
5111BC box thermistor error - TH11 open/short circuit, disconnected from board/pipe
5112BC box thermistor error - TH10 open/short circuit, disconnected from board/pipe
5113BC box thermistor error - TH open/short circuit, disconnected from board/pipe
5114BC box thermistor error - TH open/short circuit, disconnected from board/pipe
5115BC box thermistor error - TH15 open/short circuit, disconnected from board/pipe
5116BC box thermistor error - TH16 open/short circuit, disconnected from board/pipe
5201Pressure sensor fault outdoor unit/BC box - check fault code address/SW1 pressure sensor readings
5202Pressure sensor fault (PS2) in the BC box
5203Pressure sensor fault (PS3) in the BC box
5300A-Control UH fault - see Mr Slim fault code list
5301Current sensor fault, ACCT or DCCT - check inv. error details
5401Temperature sensor fault - check CN30 for humidity sensor
5701Loose float switch connector - check switch, check CN4F on indoor unit
6201TB7 transmission line communication error - check for voltage abnormality/short
6202Transmission processor hardware error - check for noise/short on M-Net cable
6600Repeat address fault - two or more units are assigned the same address - correct the repeated address
6601Polarity setting error - no voltage or short circuit on the m-net transmission line
6602Hardware error of transmission processor. Noise interference. Polarity problem on TB7
6603Bus circuit busy - check if indoor unit, Lossnay unit or anything else has been wired into TB7, instead of TB3
6607Communication issue - no response back from unit whilst system is operational
6608Communication error - loss of voltage or noise entering the transmission line
6700K control communication error - R22 type unit connected onto M-Net circuit comms error
6701K control communication error - R22 type unit connected onto M-Net circuit comms error
6702K control duplicate address error - two or more R22 type units connected onto M-Net circuit with the same address
6750K control communication error - R22 type unit connected onto M-Net circuit comms error
6751R22 R/A thermistor fault (P1)
6752R22 frost protection at I/C (P6)
6753Comms fault between O/C and I/C
6754R22 drain fault (P5)
6755R22 drain fault (P5)
6756R22 frost protection at I/C (P6)
6757System error
6758Comms fault between I/C and O/C
6761R22 R/A thermistor fault (P1)
6762R22 TH2 fault check resistance (P2)
6763R22 Comms fault between I/C and O/C
6764R22 drain fault (P4)
6765R22 drain fault (P5)
6766R22 frost protection at I/C (P6)
6767R22 comms fault between I/C and O/C
6771K abnormality - high pressure abnormality or low pressure abnormality
6772K abnormality - inner thermostat function, discharge temperature abnormality, shell thermostat function, over current protection
6773K abnormality - radiator plate thermostat function
6774K abnormality - outdoor thermistor abnormality
6775K abnormality - pressure sensor abnormality, indoor/outdoor communication error
6776K abnormality - over current shut-off
6777K abnormality - system error
6778K abnormality - normal
6779K abnormality - refrigerant overcharge, abnormal voltage, abnormal CT sensor
6830Comms fault between I/C and R/C check connections to MA R/C and check for 12Vdc check R/C not set sub controller
6831MA R/C communication fault - check connections on TB15 or that the controller was removed while the I/C was powered
6832MA controller comms fault - check cable length no bigger than 500m, check connection and type of cable used, check R/C not set sub on field settings
6833MA controller comms fault check cable length no bigger than 500m, check connection and type of cable used, check R/C not set sub on field settings
6834MA Controller comms fault - check cable length no bigger than 500m, check connection and type of cable used, check R/C not set sub on field settings
6840A-Control E6/E8 fault - see Mr Slim fault code list
6841A-Control E7/E9 fault - see Mr Slim fault code list
6844A-Control EA fault - see Mr Slim fault code list
6845A-Control Eb fault - see Mr Slim fault code list
6846A-Control EC fault - see Mr Slim fault code list
7100Over capacity - (R2 150% index exceeded) (Y 130% index exceeded)
7101Capacity setting error - SW2 set wrong on indoors, SW5 on YHMA outdoor, (SW3-10 on older kit)
7102Error in number of connected units - loss of M-Net voltage (short or break), no power to BC, wrong SW5 setting on box, wrong box type
7105Address setting error - OC or BC addressed wrong
7106Attribute setting error - SW3-1 setting on a GUF
7107Port setting error - check if too much capacity on a single port, wiring SW2 setting, wrong SW14 setting or wrong units on a box when using multiple boxes
7110Check SW5-7 is correctly set
7111Remote control sensor fault - SW1 - 1 on and no controllers fitted or faulty remote controller
7113Function setting error - wrong SW5 setting or wrong resistors fitted on YHM-A
7117Model setting error - SW5 set wrong or wrong resistors in
7130Incompatible equipment on M-Net - check split with MAC 399 wired onto the TB5 line TB5 line, not the TB7



4- Mitsubishi inverter Cassette AC Error Codes

Mitsubishi inverter Cassette AC Error Codes
Mitsubishi inverter Cassette AC Error Codes – How To Troubleshoot and Fix?
Alarm CodesSolutions
P1Intake sensor error
P2Pipe (TH2) sensor error
P9Pipe (TH5) sensor error
E6,E7Indoor/outdoor unit communication error
P4Drain sensor error/Float switch connector (CN4F) open
P5Drain pump error
PAForced compressor stop (due to water leakage abnormality)
P6Freezing/Overheating protection operation
EECommunication error between indoor and outdoor units
P8Pipe temperature error
E4,E5Remote controller signal receiving error
FbIndoor unit control system error (memory error, etc.)
PLRefrigerant circuit abnormal
E0,E3Remote controller transmission error
E1,E2Remote controller control board error
E9Indoor/outdoor unit communication error (Transmitting error) (Outdoor unit)
UPCompressor overcurrent interruption
U3,U4Open/short of outdoor unit thermistors
UFCompressor overcurrent interruption (When compressor locked)
U2Abnormal high discharging temperature/49C operated/ insufficient refrigerant
U1,UdAbnormal high pressure (63H operated)/Overheating protection operation
U5Abnormal temperature of heat sink
U8Outdoor unit fan protection stop
U6Compressor overcurrent interruption/Abnormal of power module
U7Abnormality of super heat due to low discharge temperature
U9,UHAbnormality such as overvoltage or voltage shortage and abnormal synchronous signal to main circuit/Current sensor error



5- Mitsubishi Ecodan Error Codes

Ecodan air source heat pumps use 1kW of electrical energy input and take 2.2kW of low temperature renewable heat energy from the air, producing a high efficient 3.2kW heat energy output. This heats refrigerant in the system which in turn heats water for domestic hot water and space heating.

Mitsubishi Ecodan Error Codes
Mitsubishi Ecodan Error Codes – Details and Solution
Fault CodesProblem
F3Low pressure switch failure - check connection on the board and continuity of switch
F5High pressure switch failure - check connection onto board and continuity of switch
F9Both pressure switch contacts are open at the same time - check connection onto board and continuity of switch and for a potential board failure
EAMis-wiring fault between FTC and Ecodan - check S1,S2,S3 also check voltages and comms
EBMis-wiring fault between FTC and Ecodan - Check S1,S2,S3 also check voltages and comms
ECUnit cannot finish start up process - generally caused by a comms fault
U1Ecodan high pressure fault - mainly caused by incorrect water flow rates - check with flow setter
U2Ecodan high compressor discharge temperature - mainly caused by refrigerant shortage or dirty condenser
U3Ecodan discharge thermistor problem - mainly caused by TH4 discharge thermistor - open/close circuit
U4Open or close circuit Ecodan thermistors (TH3, TH32, TH33, TH6, TH7, TH8) - open or close circuit or disconnected from main board
U5Inverter heat sink overheat protection (W50 and W85 models 77°C, HW140 model 95°C - reduced air flow through Ecodan - faulty fan motor
U6Inverter/Compressor over current - system indicates possible IPM error
U8Ecodan fan motor problem - mainly caused by DC fan motor being disconnected, connected or obstructed with the power on or possible main board fault
U9Over voltage or under voltage - mainly caused by either CN2 or CN5 loose or disconnected or decrease of mains power supply
UDOverheat protection TH3 ≥ 70°C or 63HS ≥ 70°C saturation temperature
UFCompressor over current/Compressor lock - occurs within 30 seconds of compressor start
UHAbnormal running current - < 1A or > 40A detected during operation - check CN5 connections
ULOpen circuit (63L )
UPOver current detected after 30 seconds of operation - do an inverter test to determine outputs balanced
E0Transmitting Error PAR W21 - check refrigerant address on SW1 of Ecodan
E1Faulty controller
E3Transmitting Error (PAR W21) - check refrigerant address on SW1 of Ecodan
E4Receiving Error (PAR W21) - check refrigerant address of SW1 on Ecodan
E5Receiving Error (PAR W21) - check refrigerant address of SW1 on Ecodan
E6Indoor/Outdoor communication error - mainly due to Ecodan being powered up before FTC(2)
E8Indoor/Outdoor communication error - mainly due to Ecodan being powered up before FTC(2)
E9Indoor/Outdoor communication error - mainly due to Ecodan being powered up before FTC(2)
EFNon-defined error code - noise interference - power down Ecodan for 30 seconds then switch back on
EDSerial communication fault between Ecodan main board and Ecodan inverter board - mainly due to loose CN2 or CN5 cable
P1Flow temp sensor fault - TH1 not connected, short or open circuit
P6Over heating at heat exchanger - lack of water flow, air in the system, flow rate incorrectly set, blockage or pump problem
P8No temp change at plate heat exchanger - problem with flow rate (too high) - incorrect sizing of system
P9TH5 Fault - TH5 not connected, short or open circuit, FTC not configured for heating only
PEInlet water temp fault - TH32 is below 10°C whilst compressor is in operation - possible thermistor out of range, short of gas, incorrect sizing of radiator or problem in the water circuit (blockage, pump failure etc)



6- Mitsubishi Hot Water Heat Pumps PWFY Series Error Codes

Mitsubishi Hot Water Heat Pumps PWFY Series Error Codes
Mitsubishi Hot Water Heat Pumps PWFY Series Error Codes

12.5kW Hot Water Module. Flexibility to create very large systems. Can be installed in conjunction with City Multi VRF air conditioning. Available in one size: PWFY-P100VM-E-BU (12.5kW heating) which is modular to allow creation of larger solutions. Sanitary water heating has suitable applications in: hotels and motels, apartments, commercial kitchens and laundries, office buildings, food processing industry, heat recovery from air conditioning systems into sanitary water storage, and direct sanitary water heating is also possible.

Fault CodesProblem
403Comms fault between boards - check between control board an inverter board
403Comms fault between boards - check between control board an fan board
1102High compressor discharge temperature - discharge temp has exceeded 115°C or more - check if short of refrigerant or discharge thermistor
1301Low pressure fault - low pressure sensor sensing less than 1 bar immediately before starting
1302High pressure fault - check system pressure exceded 32.3 bar, check high pressure sensor (63HS) against gauge pressure
2000Pump interlock error - pump interlock open whilst system in operation
2134Abnormal water temperature (TH6) has exceded 85°C
2135Water source heat exchanger frozen (TH6) or (TH8) reading 2°C
4102Open phase fault - check power supply and noise filter for loss of phase, check wiring and fuses
4115Power supply abnormal - check power, fuses, connections and PCB
4220Low inverter board BUS voltage - less than 200Vdc is detected during in inverter operation - check mains supply
4220Bus voltage error PAM damage - replace the inverter board
4220High bus voltage Vdc>380v - check power supply and possible faulty inverter board
4220Replace inverter board
4230High temperature (85°C) on heat sink on inverter - check for blockages in air duct, failure of INV fan failure of INV fan or failure of thermistor (THHS)
4250Over current protection - inverter IPM problem or compressor lock - check inverter balance
4250ACCT sensor over current detection 34.5A peak or 16A rms is detected - check the compressor for failure, or possible inverter board failure
5102Thermistor TH22 failure
5103Thermistor TH13 or TH23 failure
5104Thermistor TH11 failure
5106Thermistor TH6 failure
5108Thermistor TH8 failure
5110Thermistor THHS failure
5201High pressure sensor fault - check the system pressure is >1 bar, check the operation of 63HS high pressure transducer
5202Pressure sensor fault
5301Current sensor fault, ACCT or DCCT - check inv. error details
5301Low output current <1.5A rms whilst the inverter is in operation



7- Mitsubishi Packaged Hot Water Heat Pump CAHV Error Codes

Mitsubishi Packaged Hot Water Heat Pump CAHV Error Codes
Mitsubishi Packaged Hot Water Heat Pump CAHV Error Codes

45kW Packaged Hot Water Heat Pump. Can be combined to max. 70kW. “Flash-injection Circuit”, which is designed for our ZUBADAN CITY MULTI (air conditioning system for cold regions), is mounted in our new Hot Water Heat Pump. By utilizing our advanced “Flash-injection Circuit” and the latest high-efficiency compressor, Hot Water Heat Pump provides hot water upto 70°C, and produces less capacity drop at low outdoor temperature.

Error CodesProblem
AFSAWater supply cut-off (flow switch has been triggered) - check flow switch and wiring
AHP1High pressure fault - check water flow, possible high pressure sensor fault LEV fault
AdSHCompressor crank case temperature of 10°C or less for 40 minutes while compressor in operation - check for possible failure of fan motor, low pressure sensor, compressor shell thermistor, high pressure sensor, discharge thermistor (TH1 TH5), LEV or SV2
1303Low pressure protection low pressure below 6 bar within 30 sec of start up - possible failure of LP sensor, air inlet thermistor fault (TH4 TH8), suction temperature (TH2 TH6), LEV bypass check valve
1103Compressor shell bottom temperature exceeded 80°C detected whilst compressor running
5109Compressor shell thermistor faulty (TH3 TH6), LEV failure
5110Outside temperature thermistor fault - check TH9
5112Water inlet temperature - check TH10 main circuit
5111Water inlet temperature - check TH12 sub circuit
5113Outlet water temperature - check TH11 main circuit
5103Outlet water temperature - check TH12 sub circuit
5107Compressor shell temperature - check TH3 main circuit
5101Compressor shell temperature - check TH7 sub circuit
5105Discharge temperature - check TH1 main circuit
5102Discharge temperature - check TH5 sub circuit
5106Inlet temperature - check TH2 main circuit
5104Inlet temperature - check TH6 sub circuit
5108Air to refrigerant heat exchanger inlet temperature - check TH4 main circuit
5114Air to refrigerant heat exchanger inlet temperature - check TH8 sub circuit
5115Common return water when using multiple outdoors - check TH14
5117Common return water when using multiple outdoors - check TH15
5118High pressure sensor or high pressure fault - check 63HS sensor or 63H (hp switch)
7113Low pressure sensor low or low pressure fault - check 63LS
7117Model setting error 1 - mis-set switch
4115Model setting error 2 - faulty Z21 resistor
A471Power supply frequency fault - power supply frequency is not 50Hz or 60Hz
1104Discharge temperature fault - 120°C detected during compressor operation - check water flow, pump, high pressure sensor fault or LEV fault
AC61Power supply fault - check transmission power supply or if PCB faulty

8- Mitsubishi Electric MR Slim Operation Light Blinking




Mitsubishi Air Conditioner Operation Light Flashing
Mitsubishi Air Conditioner Operation Light Flashing – Fix it

Flashing of POWER lamp indicates abnormalities. Before taking measures, make sure that the symptom reappears for accurate troubleshooting. Self check table

When the indoor unit has started operation and the above detection method has detected an abnormality (the first detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with OPERATION INDICATOR lamp flashing.

Operation indicator lampSolution
POWER lamp flashes. 0.5-second ONMis-Wiring or serial signal. Outdoor unit does not operate. When the serial signal form the outdoor unit is not received for a maximum of 6 minutes.
POWER lamp lights upOut door control system. Outdoor unit does not operate. When it cannot properly read data in the nonvolatile memory of the inverter P.C. board or the outdoor electronic control P.C. board. Check the blinking pattern of the LED on the inverter P.C. board or the outdoor lectronic control P.C. board.
POWER lamp flashes. 2-time flashIndoor coil thermistor. Room temperature thermistor. Indoor unit and outdoor unit do not operate. When the indoor coil or the room temperature thermistor is short or open circuit.
POWER lamp flashes. 3-time flashIndoor fan motor. Indoor unit and outdoor unit do not operate. When the rotational frequency feedback signal is not emit during the indoor fan operation. 
POWER lamp flashes. 5-time flashOut door power system. Indoor unit and outdoor unit do not operate. When it consecutively occurs 3 times that the compressor stops for overcurrent protection or start-up failure protection witth in 1 minute after start-up. 
POWER lamp flashes. 6-time flashOutdoor thermistors. Indoor unit and outdoor unit do not operate. When the outdoor thermistors short or open circuit during the compressor operation.
POWER lamp flashes. 7-time flashOut door control system. Indoor unit and outdoor unit do not operate. When it cannot properly read data in the nonvolatile memory of the inverter P.C. board or the outdoor electronic control P.C. board.
POWER lamp flashes. 14-time flashOther abnonmality. Indoor unit and outdoor unit do not operate. An abnormality other than above mentioned is deteced. Confirm the abnormarity in detail using the failure mode recall function.



Mitsubishi Split Air Conditioner Timer Light Blinking

LED1 (Green)-LED2 (Red)Contents
3 blinking-1 blinkingAbnormality of comp. surface thermistor (TH32) and discharging temperature (TH4)
3 blinking-2 blinkingAbnormal high pressure (High pressure switch 63H operated.)
3 blinking-3 blinkingAbnormality of outdoor fan motor rotational speed. Protection from overheat operation(TH3).
3 blinking-4 blinkingCompressor overcurrent breaking (Start-up locked). Compressor overcurrent breaking. Abnormality of current sensor (P.B.). Abnormality of power module.
3 blinking-5 blinkingOpen/short of discharge thermistor (TH4) and comp. surface thermistor (TH32). Open/short of outdoor thermistors (TH3, TH6, TH7 and TH8).
3 blinking-6 blinkingAbnormality of heatsink temperature
3 blinking-7 blinkingAbnormality of voltage
4 blinking-1 blinkingAbnormality of room temperature thermistor (TH1). Abnormality of pipe temperature thermistor /Liquid (TH2). Abnormality of pipe temperature thermistor/Condenser-Evaporator.
4 blinking-2 blinkingAbnormality of drain sensor (DS) Float switch(FS) connector open. Indoor drain overflow protection.
4 blinking-3 blinkingFreezing (cooling)/overheating (heating) protection
4 blinking-4 blinkingAbnormality of pipe temperature
Mitsubishi Split Air Conditioner Timer Light Blinking
Mitsubishi Split Air Conditioner Timer Light Blinking



Mitsubishi Electric Aircon RedLINK Error Codes

Error Codes Meaning
E0 27Verify device temperature is within operating range. If within range for at least 30 minutes and problem persists, replace Remote Controller.
E0 91Communication was established between wireless receiver and the indoor unit, but communication has been lost for 10 minutes. Check cable connection. Try replacing the cable.
E1 29Attempting to connect incompatible wireless devices.
E1 34Low signal strength. Move wireless device to a different location and try again.
E1 38Make sure Connect light on wireless receiver is flashing and you are 2+ feet away from wireless receiver.
E1 54Indoor unit does not support wireless receiver.

9- Troubleshooting

Mitsubishi Air Conditioning Troubleshooting
Mitsubishi Air Conditioning Troubleshooting

Even if these items are checked, when the unit does not recover from the trouble, stop using the air conditioner and consult your dealer.

Symptom: The unit cannot be operated.

Explanation & Check points:

  • Is the breaker turned on?
  • Is the power supply plug connected?
  • Is the ON timer set?

Symptom: The horizontal vane does not move.

Explanation & Check points:

  • Are the horizontal vane and the vertical vane installed correctly?
  • Is the fan guard deformed?
  • When the breaker is turned on, the horizontal vanes’ position will be reset in about a minute. After the reset has completed, the normal horizontal vanes’ operation resumes. The same is true in the emergency cooling operation.

Symptom: The unit cannot be operated for about 3 minutes when restarted.

Explanation & Check points: This protects the unit according to instructions from the microprocessor. Please wait.

Symptom: Mist is discharged from the air outlet of the indoor unit.

Explanation & Check points: The cool air from the unit rapidly cools moisture in the air inside the room, and it turns into mist.

Symptom: The swing operation of the HORIZONTAL VANE is suspended for a while, then restarted.



Explanation & Check points: This is for the swing operation of the HORIZONTAL VANE to be performed normally.

Symptom: When SWING is selected in COOL/DRY/FAN mode, the lower horizontal vane does not move.

Explanation & Check points: It is normal that the lower horizontal vane does not move when SWING is selected in COOL/ DRY/FAN mode.

Symptom: The airfl ow direction changes during operation. The direction of the horizontal vane cannot be adjusted with the remote controller.

Explanation & Check points:

  • When the unit is operated in COOL or DRY mode, if the operation continues with air blowing down for 0.5 to 1 hour, the direction of the airfl ow is automatically set to horizontal position to prevent water from condensing and dripping.
  • In the heating operation, if the airfl ow temperature is too low or when defrosting is being done, the horizontal vane is automatically set to horizontal position.

Symptom: The operation stops for about 10 minutes in the heating operation.

Explanation & Check points: Outdoor unit is in defrost. Since this is completed in max.10 minutes, please wait. (When the outside temperature is too low and humidity is too high, frost is formed.)

Symptom: The unit starts operation by itself when the main power is turned on, but hasn’t received sign from the remote controller.

Explanation & Check points: These models are equipped with an auto restart function. When the main power is turned off without stopping the unit with the remote controller and is turned on again, the unit starts operation automatically in the same mode as the one set with the remote controller just before the shutoff of the main power. Refer to “Auto restart function”

Symptom: The indoor unit which is not operating becomes warm and a sound, similar to water fl owing, is heard from the unit.

Explanation & Check points: A small amount of refrigerant continues to fl ow into the indoor unit even though it is not operating.

Symptom: When heating operation is selected, operation does not start right away.

Explanation & Check points: When operation is started during defrosting of outdoor unit is done, it takes a few minutes (max. 10 minutes) to blow out warm air.

Symptom: Water leaks from the outdoor unit.

Explanation & Check points:

  • During COOL and DRY operations, pipe or pipe connecting sections are cooled and this causes water to condense.
  • In the heating operation, water condensed on the heat exchanger drips down.
  • In the heating operation, the defrosting operation makes ice forming on the outdoor unit melt and drip down.

Symptom: White smoke is discharged from the outdoor unit.

Explanation & Check points: In the heating operation, vapor generated by the defrosting operation looks like white smoke.

Symptom: The display on the remote controller does not appear or it is dim. The indoor unit does not respond to the remote control signal.

Explanation & Check points:

  • Are the batteries exhausted?
  • Is the polarity (+, -) of the batteries correct?
  • Are any buttons on the remote controller of other electric appliances being pressed?

Symptom: The room cannot be cooled or heated sufficiently.

Explanation & Check points:

  • Is the temperature setting appropriate?
  • Is the fan setting appropriate? Please change fan speed to High or Super High.
  • Are the fi lters clean?
  • Is the fan or heat exchanger of the indoor unit clean?
  • Are there any obstacles blocking the air inlet or outlet of the indoor or outdoor unit?
  • Is a window or door open?
  • It may take a certain time to reach the setting temperature or may not reach that dependingon the size of the room, the ambient temperature, and the like.

Symptom: Air does not blow out soon in the heating operation.

Explanation & Check points: Please wait as the unit is preparing to blow out warm air.

Symptom: The air from the indoor unit smells strange.

Explanation & Check points:



  • Are the fi lters clean?
  • Is the fan or heat exchanger of the indoor unit clean?
  • The unit may suck in an odor adhering to the wall, carpet, furniture, cloth, etc. and blow it out with the air.

Symptom: Cracking sound is heard.

Explanation & Check points: This sound is generated by the expansion/contraction of the front panel, etc. due to change in temperature.

Symptom: “Burbling” sound is heard

Explanation & Check points: This sound is heard when the outside air is absorbed from the drain hose by turning on the range hood or the ventilation fan, making water fl owing in the drain hose to spout out. This sound is also heard when the outside air blows into the drain hose in case the outside wind is strong.

Symptom: Weekly timer does not operate according to settings.

Explanation & Check points:

  • Is the ON/OFF timer set?
  • Transmit the setting information of the weekly timer to the indoor unit again. When the information is successfully received, a long beep will sound from the indoor unit. If information fails to be received, 3 short beeps will be heard. Ensure information is successfully received.
  • When a power failure occurs and the main power turns off, the indoor unit built-in clock will be incorrect. As a result, the weekly timer may not work normally.

In the following cases, stop using the air conditioner and consult your dealer

  • When water leaks or drips from the indoor unit.
  • When the operation indicator lamp blinks. Except for when the lamp of a multi unit blinks while the unit is on standby.
  • When the breaker trips frequently.
  • The remote control signal is not received in a room where an electronic ON/ OFF type fl uorescent lamp (inverter-type fl uorescent lamp, etc.) is used.
  • Operation of the air conditioner interferes with radio or TV reception. An amplifi er may be required for the affected device.
  • When an abnormal sound is heard.

Mitsubishi Electric Mr.Slim AC Electrical Wiring Diagram

Mitsubishi Electric Mr.Slim ac electrical wiring diagram
Mitsubishi Electric Mr.Slim ac electrical wiring diagram

Mitsubishi Electric MR Slim AC Refrigerator Diagram

mitsubishi electric mr slim ac refrigerator diagram
mitsubishi electric mr slim ac refrigerator diagram

 

Mitsubishi Air Conditioning Service Handbook PDF

Mitsubishi Air Conditioning Service Manual PDF

Mitsubishi Electric MRCH1 Remote ControllerOperating Manual PDF

Mitsubishi Electric Split AC Manual MSZ-AP22VGD PDF 

Mhk1 Wireless Remote Receiver Kit Manual PDF

MIFH1, MRCH1, MCCH1, MOS1 Controller Kit Installation Manual PDF

Mitsubishi Air Conditioning Error Codes PDF – R410A Systems




*PLEASE SEND ME ANY COMMENT, SUGGESTION OR CORRECTION YOU MAY HAVE.
7 Comments

Add a Comment

Your email address will not be published. Required fields are marked *