Mitsubishi mr slim troubleshooting

Searching for Mr slim error codes to troubleshoot your aircon? You come to the right place. After you get the Mr slim error codes, you will be able to troubleshoot the system and know which part needs to be replaced or repaired.

Mitsubishi Mr slim P series (A) series air conditioner error codes

Mitsubishi Mr slim P series (A) series A0

Central controller: 6600

Description : Duplicate address, Lossnay units attached with the same address.

Cause : Units attached with the same address

Check procedure : Change the address and reset the unit’s power

Mitsubishi Mr slim P series (A) series A2

Central controller: 6602

Description: Hardware error of transmission processor. It is also termed as Lossnay board fault.

Cause:

  1. The waveform is transformed on transmission wiring.
  2. Lossnay board fault

Check procedure: You have to simply check the comms wiring.

Mitsubishi Mr slim P series (A) series A3

Central controller: 6603

Description: The transmission line is busy when Mr. Slim is connected to the M-net transmission line.

Cause: Its cause is no data could be transmitted for 8 minutes.

Check procedure: Check A-MNetconnections(TB7)

Mitsubishi Mr slim P series (A) series A6

Central controller: 6606

Description: This error indicates the communication error with a communication processor.

Cause: The main cause is that the Lossnay address is not transmitted.

Check procedure: Check M.Net voltage

Mitsubishi Mr slim P series (A) series A7

Central controller: 6607

Description: This error indicates:

  • Communication error
  • Range of transmission wiring exceeded
  • Faulty A-MNet converter

Cause:

  1. Range of transmission wiring exceeded
  2. Faulty A-MNet converter

Check procedure Check the M-Net wiring. Check your M-Net voltage. Replace the M-Net converter.

Mitsubishi Mr slim P series (A) series A8

Central controller: 6608

Description: It indicates M-Net no response or you can say communication error.

Cause:

  1. Range of the transmission wiring exceeded
  2. Faulty A-MNet converter
  3. The incorrect wire is used for the M-Net connection.

Check procedure: Check your M-Net wiring and the cable type used should be 2-core screened CY cable, 1.5mm

Mitsubishi Mr slim P series (A) series EA

Central controller: 6844

Description: This error is caused when more than 1 unit is connected in a group resulting in miswiring or communication error.

Cause:

  1. Miswiring
  2. Loose interconnecting cables
  3. Noise interference
  4. More than one unit in a group

Check procedure: Check the wiring of interconnecting cables. Check your master and slave addressing when more than one unit is connected in a group.

Mitsubishi Mr slim P series (A) series EB

Central controller: 6845

Description: In this error, miswiring and loose interconnecting cables are involved.

Cause:

  1. Loose interconnecting cables
  2. Noise interference
  3. More than one unit in a group

Check procedure: Check the wiring of interconnecting cables. Check your master and slave addressing when more than one unit is connected in a group.

Mitsubishi Mr slim P series (A) series EC

Central controller: 6846

Description: This error indicates the indoor FTC can’t finish the process or unable to communicate to outdoor Ecodan.

Cause:

  1. Loss of or no communication between indoor FTC and outdoor Ecodan.
  2. Poor connection of interconnecting cables
  3. Not correct 12-24 Vdc fluctuating voltage between S2 and S3

Check procedure:

  • First of all, check the voltage on interconnecting cables on S1-S2-S3
  • Check continuity on fuses
  • Check 240 V supply to indoor FTC and outdoor Ecodan

Mitsubishi Mr slim P series (A) series ED

Central controller: 403

Description: This error indicates the serial communication fault between the Ecodan main control board and the Ecodan power board.

Cause:

  1. Loose CN2 or CN5 connection between the two boards
  2. Control board failure

Check procedure:

  • Check the loose plugs
  • Check the voltage

Mitsubishi Mr slim P series (A) series EF

Central controller: 6607

Description: It is not as such a defined error code.

Cause: The main cause is Noise interference

Check procedure: Power down your system and then switch back on.

Mitsubishi Mr slim P series (A) series E0

Description: This code indicates the remote controller transmitting error.

Cause:

  1. Incorrect wiring of remote
  2. Incorrect dip switch setting if units are grouped

Check procedure:

  • If grouped then check unit addressing
  • Check remote is wired only to master indoor unit

Mitsubishi Mr slim P series (A) series E1

Description: This code indicates the remote controller issue.

Cause:

  1. Faulty controller
  2. Poor wiring connection
  3. Abnormal voltage to the remote controller

Check procedure: Check the wiring of the remote controller onto the FTC terminals and ensure the 12 Vdc down to the remote control.

Mitsubishi Mr slim P series (A) series E2

Description: It is the remote controller transmitting error.

Cause:

  1. Incorrect wiring of the remote
  2. Incorrect dip switch setting

Check procedure

  • If grouped then check unit addressing
  • Check whether the remote is wired to the master unit only

Mitsubishi Mr slim P series (A) series E3

Description: It is the remote controller transmitting error.

Cause:

  1. Incorrect wiring of the remote
  2. Incorrect dip switch setting

Check procedure:

  • If grouped then check unit addressing
  • Check whether the remote is wired to the master unit only

Mitsubishi Mr slim P series (A) series E4

Description: It is a remote controller communication error.

Cause:

  1. Incorrect wiring of remote
  2. If the controller doesn’t have the correct 12 Vdc supply

Check procedure:

  • Check for 12 Vdc down to the controller and make sure LED 2 is lit on the FTC board
  • Check the SW1 sip switches on the outdoor unit are set correctly

Mitsubishi Mr slim P series (A) series E5

Description: It is again a remote controller transmitting error.

Cause:

  1. Remote controller incorrectly wired
  2. The controller doesn’t have the correct 12 Vdc supply

Check procedure:

  • Check for 12 Vdc down to the controller and make sure LED 2 is lit on the FTC board
  • Check the SW1 sip switches on the outdoor unit are set correctly

Mitsubishi Mr slim P series (A) series E6

Central controller: 6840

Description: This indicates the indoor to outdoor communication fault.

Cause:

  1. No communication between FTC and outdoor Ecodan
  2. Poor connection of interconnecting cables
  3. Incorrect supply of 12-24 Vdc fluctuating voltage between S1 and S3

Check procedure:

  • Reset power supply first then the outdoor
  • Check interconnecting cables and voltage
  • Check indoor FTC LEDs
  • Power back up the indoor

Mitsubishi Mr slim P series (A) series E7

Description: It is the comms failure indoor to outdoor (S2/S3)

Cause:

  1. Miswiring
  2. Incorrect system powered up.

Check procedure:

  • Check the pumps wired in
  • Check the indoor isolator
  • Repower indoor,  then outdoor

Mitsubishi Mr slim P series (A) series E8

Central controller: 6840

Description: It is the comms failure indoor to outdoor (S2/S3)

Cause

  1. Miswiring
  2. Incorrect system powered up.

Check procedure

  • Check the pumps wired in
  • Check the indoor isolator
  • Repower indoor, then outdoor

Mitsubishi Mr slim P series (A) series E9

Central controller: 6841

Description: It is the comms failure indoor to outdoor (S2/S3)

Cause:

  1. Miswiring
  2. Incorrect system powered up.

Check procedure

  • Check the pumps wired in
  • Check the indoor isolator
  • Repower indoor, then outdoor

Mitsubishi Mr slim P series (A) series FA

Central controller: 4108

Description: This is the error termed as 51 CM connector open circuit

Cause: Thermal relay is an open circuit

Check procedure: Check the thermal relay for disconnection, contact failure, or defective connection.

Mitsubishi Mr slim P series (A) series F1

Central controller: 4103

Description: This is termed reverse-phase detection.

Cause:

  1. Causes are as follows:
  2. Incorrect power supply
  3. Two phases are wrong way round

Check procedure:

  • Check power supply
  • Try to swap 2 phases round

Mitsubishi Mr slim P series (A) series F2

Central controller: 4102

Description: In this error, the L3 phase opens.

Cause:

  1. The main cause is:
  2. The power supply is not correct

Check procedure:

  • Check power supply
  • Check open circuit devices

Mitsubishi Mr slim P series (A) series F3

Central controller: 5202

Description: In this error, lower pressure switch open circuit or incorrect contact to the control board

Cause:

  1. The causes are the following:
  2. Low-pressure switch detecting low refrigerant pressure in the outdoor unit.
  3. The contact of the switch has been damaged.

Check procedure

  • Check continuity through the low-pressure switch
  • Check the refrigerant gas pressure

Mitsubishi Mr slim P series (A) series F4

Central controller: 4124

Description: This error indicates the 49C open circuit.

Cause:

  1. Compressor
  2. Inner thermostat
  3. Open circuit
  4. Contact failure

Check procedure: Check inner thermostat

Mitsubishi Mr slim P series (A) series F7

Central controller: 4118

Description: This error indicates the phase detection circuit failure

Cause:

  1. The cause is the power supply phase reversed

Check procedure

  • Check power supply
  • Swap two phases over

Mitsubishi Mr slim P series (A) series F8

Description: In this error, no input is detected at the outdoor unit

Cause: This is caused due to defective outdoor board

Check procedure: Check whether the main power is ok.

Mitsubishi Mr slim P series (A) series F9

Central controller: 4119

Description: In this error, both the high and low-pressure switches open the circuit.

Cause:

  1. Both the high and low-pressure switches open the circuit.
  2. Control board fault

Check procedure: Check both the switches and check their connections to the control board.

Mitsubishi Mr slim P series (A) series P1

Description: it represents a room sensor fault.

Cause:

It can be caused by different factors as follows:

  1. Faulty thermistor
  2. Incorrect sensor setting
  3. Loose wiring

Check procedure: Check the thermistor for the circuit and then check the wiring connection.  Also, check the settings of the main controller, Initial setting>Room sensor setting>Sensor settings>Sensor setting, and then change sensing point from TH1 to main R/C.

Mitsubishi Mr slim P series (A) series P2

Description: Indoor liquid pipe thermistor fault. And the PCB detects incorrect temperature reading from the thermistor.

Cause:

  1. It is caused due to
  2. Faulty thermistor
  3. A damaged cable or poor connection to PCB.

Check procedure: Check connection of thermistor on PCB and thermistor wiring.

Mitsubishi Mr slim P series (A) series U1

Central controller: 1302

Description: It is the error indicating Ecodan high-pressure fault.

Cause: It is caused due to the abnormal water flow on the primary circuit.

Check procedure:

  • Check flow rate on the sensor
  • Check zone valves
  • Check water pressure

Mitsubishi Mr slim P series (A) series U2

Central controller: 1102

Description: This is the error of Ecodan high compressor discharge temperature.

Cause:

The main causes are as following :

  1. Refrigerant may leak
  2. Water flow issue
  3. Thermistor detecting abnormally high temperature

Check procedure:

  • Check airflow
  • Check water flow
  • Confirm the dip switch

Mitsubishi Mr slim P series (A) series U6

Central controller: 4250

Description: This is the overcurrent fault

Cause:

  1. Compressor issue like winding failure
  2. Inverter output failure

Check procedure:

  • Measure the resistance of the compressor for a dead circuit
  • Carry out an inverter output test

Other Mitsubishi aircon models, please refer to our mitsubishi fault code list guide.

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