Mitsubishi Electric PK18FK

Questions and Answers

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Paula AveryAug 8, 2025
What to do if check code 'EO' appears on Mitsubishi Electric PK18FK Air Conditioner when remote controller power button is turned on?
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  Trevor DouglasAug 8, 2025
  If the check code 'EO' appears on your Mitsubishi Electric Air Conditioner when you turn on the remote controller, it may indicate a signal transmission error between the indoor unit and the remote controller. To address this, connect a sub remote controller and turn the circuit breaker ON. If the 'centrally controlled' display remains, replace the indoor controller board. If the display disappears, turn the remote controller POWER button ON and check as follows.
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Shawn HowardAug 15, 2025
Why Mitsubishi Electric PK18FK Air Conditioner remote controller display does not appear when turning power button on?
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  pjohnsonAug 15, 2025
  If the Mitsubishi Electric Air Conditioner remote controller display doesn't appear when you turn the power on, it could be due to several reasons. It might be a damaged remote controller, a short circuit in the transmission wire, bad contact at indoor CN40, CN40 being attached to a sub unit, a damaged transformer, bad contact at CN4T, a blown fuse, or the circuit breaker being OFF. First, measure the voltage between the terminals of the remote controller. If there's no voltage, remove the terminals and measure the voltage between the wires. If the voltage is between 6VDC and 12V, replace the remote controller. Check each of the points mentioned. If none are defective, then replace the indoor controller board.
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Daniel FitzgeraldAug 23, 2025
What to do if Mitsubishi Electric PK18FK Air Conditioner operating display appears and disappears quickly when remote controller power button is turned on?
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  lauren80Aug 23, 2025
  If the operating display on your Mitsubishi Electric Air Conditioner appears briefly and then disappears when you turn the remote controller power button on, the issue could stem from a few things: a short circuit in the indoor/outdoor connecting wire, a short circuit in the transmission wire, a short circuit in the drain sensor heater circuit, or incorrect remote controller operation due to noise from other appliances. Check the wiring. Measure the resistance of the drain sensor connector CN50; normal resistance should be 82?. Turn the circuit breaker OFF, and then turn it back ON. If the remote controller remains abnormal after these steps, replace the indoor controller board.
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Holly RoyDec 1, 2025
How to fix 'CENTRALLY CONTROLLED' display that does not disappear on Mitsubishi Electric PK18FK Air Conditioner remote controller?
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  Diana EatonDec 1, 2025
  If the 'CENTRALLY CONTROLLED' display remains on your Mitsubishi Electric Air Conditioner remote controller, there are a few potential causes. It could be due to a wrong address setting of the remote controller or indoor controller board, a timer adapter connected to the remote controller, or a signal transmission error between the indoor unit and the remote controller. First, check the address setting of the remote controller and indoor controller. Ensure the timer adapter is used correctly. Try turning another remote controller’s DIP SW17-7 ON to make it a sub controller. Connect the sub controller to the unit, and turn the circuit breaker ON. If the 'centrally controlled' display disappears, replace the original remote controller. If the display remains, replace the indoor controller bo...

Summary

1. FEATURES

1. COMPACT DESIGN

Describes the compact size and installation flexibility.

2. A FURTHER REFINEMENT OF COMFORT WITH NOISE SUPPRESSION

Details improvements in quiet operation and airflow.

3. AUTO FLAP SHUTTER

Explains the function and operation of the auto flap shutter.

4. INSTALLATION: FAST AND ENDLESSLY ADAPTABLE

Covers aspects of installation flexibility and ease.

5. ADVANCED MICROPROCESSOR

(1) Easy to Use Microprocessor

Details the sophisticated control system and user-friendly interface.

(2) Non-polar Two-Wire Remote Controller Cables

Explains the benefits and specifications of the remote controller cabling.

(3) Automatic Cooling; Heating Changeover Operation

Describes the automatic mode switching for year-round comfort.

6. REDI-CHARGED REFRIGERANT SYSTEM

7. HIGH RELIABILITY AND EASY SERVICING

8. FOUR-WAY PIPING ACCESS MAKES INSTALLATION LAYOUT EASY

2 SPECIFICATIONS

3 DATA

Presents performance data, including cooling capacity and correction factors.

2. PERFORMANCE CURVE

PK12 FK COOLING CAPACITY

Graph showing cooling capacity vs. outdoor temperature.

PK18 FK COOLING CAPACITY

Graph showing cooling capacity vs. outdoor temperature.

3. STANDARD OPERATION DATA

4. OPERATING RANGE

Defines the operational limits for power supply and environmental conditions.

6. ADDITIONAL REFRIGERANT CHARGE (R-22 (OZ))

Provides guidelines for supplementary refrigerant charging.

4 OUTLINE AND DIMENSIONS

4.1. Indoor Unit PK12 FK

Detailed dimensions and mounting information for the PK12FK indoor unit.

4.2. Outdoor Unit PU12 EK 1

Technical drawings and dimensions for the PU12EK Outdoor Unit.

4.3. Remote controller

Diagram showing the dimensions and layout of the remote controller.

5 REFRIGRANT SYSTEM DIAGRAM

PK12;18;24 FK

Illustrates the refrigerant flow for specific indoor/outdoor unit models.

6 WIRING DIAGRAM

6.1. Indoor Unit PK12 FK

Shows the electrical connections for the PK12FK indoor unit.

6.2. Outdoor Unit PU12;18 EK 1 WIRING DIAGRAM

Electrical wiring schematic for the PU12/18EK1 outdoor unit.

7 OPERATION FLOW-CHART

MAIN OPERATION

Outlines the primary operational logic and decision points of the unit.

COOLING OPERATION

Details the sequence of operations during cooling mode.

DRY OPERATION

Explains the operational logic and control flow for dry mode.

8 MICROPROCESSOR CONTROL

1.OUTLINE OF MICROPROCESSOR CONTROL

Explains the system architecture and component interactions.

2. COOLING OPERATION

Details the thermostat function and coil frost prevention.

3. DRY OPERATION

Describes thermostat and fan control logic for dry operation.

Remote control operation and Liquid Crystal Display

5. TEST RUN FUNCTION

6. EMERGENCY OPERATION

7. Dip switch and jumper connector functions

1 On remote controller board

Describes the function of dip switches on the remote controller.

2 On indoor controller board

Explains dip switch functions for indoor unit configuration.

8. OUTDOOR MICROPROCESSOR CONTROL

8-1 Protection function

Details protection mechanisms against various operational faults.

9 TROUBLESHOOTING

1.TROUBLE IN TEST RUN

Lists common issues encountered during test run and their causes.

2. SELF DIAGNOSTIC FUNCTION WITH REMOTE CONTROLLER

Explains how malfunctions are detected and displayed.

4. TROUBLESHOOTING ACCORDING TO CHECK CODE

6. WRONG WIRING ON SITE

7. OTHER TROUBLES AND CAUSES

10 SYSTEM CONTROL

1. VARIETY OF SYSTEM CONTROL FUNCTIONS

Describes different methods for controlling multiple units.

2. GROUP CONTROL WITH A SINGLE REMOTE CONTROLLER

Explains how to connect and configure multiple units for group control.

3. CONTROL USING TWO REMOTE CONTROLLERS: OPTIONAL REMOTE CONTROLLER (PAC-SK47 RC)

4. REMOTE ON-OFF AND INDIVIDUAL REMOTE CONTROLS

6. MULTIPLE REMOTE CONTROL DISPLAY

11 DISASSEMBLY INSTRUCTIONS

1. Indoor unit PK24 FK

Step-by-step guide for disassembling the PK24FK indoor unit.

2. Outdoor unit (PU18 EK)

1. Electrical parts

Instructions for removing electrical components from the outdoor unit.

12 PARTS LIST

PK12 FK STRUCTURAL PARTS

Lists structural components for the PK12FK indoor unit with part numbers.

PK18 FK PK24 FK ELECTRICAL PARTS PK30 FK PK36 FK

Lists electrical components for PK18/24/30/36FK models.

PU12 EK;PU18 EK1 STRUCTURAL PARTS

PU12 EK;PU18 EK1 FUNCTIONAL PARTS

PU24;30 EK1 FUNCTIONAL PARTS

PU36 EK1 FUNCTIONAL PARTS

13 OPTIONAL PARTS

1. REFRIGERANT PIPES

Details optional refrigerant piping kits for different models.

2. TIMER

Information on the programmable timer and its specifications.

4. MULTIPLE REMOTE CONTROLLER ADAPTER

5. CENTRALIZED REMOTE CONTROLLER

5-3 Connection method

Explains how to connect the centralized remote controller and power supply.