Mitsubishi Electric MSZ-FX NL Series Service Manual

Split type outdoor unit

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OUTDOOR UNIT

SERVICE MANUAL

Models

MXZ-2D20NL

MXZ-3D24NL

MXZ-4D30NL

MXZ-5D36NL

MXZ-5D42NL

MXZ-2D20NL

MXZ-2D20NLHZ

MXZ-3D24NLHZ

MXZ-3D30NLHZ

Revision A:

• MXZ-3D24/4D30/5D36/5D42NL -

and MXZ-2D20/3D24/3D30NLHZ -

have been added.

OBH949 is void.

HFC

utilized

R454B

Indoor unit service manual

MSZ-FX•NL Series (OBH945)

MSZ-EX•NL Series (OBH956)

MSZ-GX•NL Series (OBH950)

MFZ-KX•NL Series (OBH944)

MLZ-KX•NL Series (OBH943)

SLZ-AF•NL Series

SEZ-AD•NL Series

PEAD-AA•NL Series

SVZ-AP•NL Series

PAA-AA•NL Series

PAA-BA•NL Series

CONTENTS

INDOOR / OUTDOOR UNIT

•

COMPATIBILITY TABLE ······························ 3

1. TECHNICAL CHANGES ······························ 4

2. SAFETY PRECAUTION ······························· 5

3. PART NAMES AND FUNCTIONS ·················16

4. SPECIFICATION ········································17

5. NOISE CRITERIA CURVES ·························25

6. OUTLINES AND DIMENSIONS ····················27

7. WIRING DIAGRAM ····································33

8. REFRIGERANT SYSTEM DIAGRAM ············39

9. DATA ·······················································52

10. ACTUATOR CONTROL ······························81

11. SERVICE FUNCTIONS ·······························82

12. TROUBLESHOOTING ································85

13. DISASSEMBLY INSTRUCTIONS ················ 107

PARTS CATALOG (OBB949)

No. OBH949

REVISED EDITION-A

Table of Contents

Troubleshooting

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July 21, 2025

What is the physical height of the MXZ5D36NL

Summary of Contents for Mitsubishi Electric MSZ-FX NL Series

Page 1: Table Of Contents
Revision A: • MXZ-3D24/4D30/5D36/5D42NL - and MXZ-2D20/3D24/3D30NLHZ - have been added. OBH949 is void. OUTDOOR UNIT No. OBH949 utilized REVISED EDITION-A SERVICE MANUAL R454B Indoor unit service manual Models MSZ-FX•NL Series (OBH945) MXZ-2D20NL MXZ-2D20NLHZ MSZ-EX•NL Series (OBH956) MXZ-3D24NL MXZ-3D24NLHZ MSZ-GX•NL Series (OBH950) MFZ-KX•NL Series (OBH944) MXZ-4D30NL MXZ-3D30NLHZ...
Page 2 Use the specified refrigerant only Never use any refrigerant other than that specified. Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of. Correct refrigerant is specified in the manuals and on the spec labels provided with our products. We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by failure to follow the instructions.
Page 3: Indoor / Outdoor Unit Compatibility Table
INDOOR / OUTDOOR UNIT COMPATIBILITY TABLE <MXZ-2D20NL> <MXZ-2D20NLHZ> Connectable indoor unit lineups (Heat pump inverter type) Connectable indoor unit lineups (Heat pump inverter type) Model type Model name Capacity class [Btu/h] Model type Model name Capacity class [Btu/h] Wall-mounted MSZ-FX**NL ●...
Page 4: Technical Changes
TECHNICAL CHANGES MXZ-2D20NL - 1. New model MXZ-3D24NL - MXZ-4D30NL - MXZ-5D36NL - MXZ-5D42NL - MXZ-2D20NLHZ - MXZ-3D24NLHZ - MXZ-3D30NLHZ - 1. New model OBH949A...
Page 5: Safety Precaution
SAFETY PRECAUTION MEANINGS OF SYMBOLS DISPLAYED ON INDOOR UNIT AND/OR OUTDOOR UNIT Refrigerant This unit uses a flammable refrigerant. WARNING Safety Group If refrigerant leaks and comes in contact with fire or heating part, it will create harmful gas and (Risk of fire) there is risk of fire.
Page 6 2-2. CAUTIONS RELATED TO R454B REFRIGERANT Cautions for units utilizing refrigerant R454B Make sure that the inside and outside of refriger- Use the following tools specifically designed for ant piping is clean and it has no contaminants use with R454B refrigerant. such as sulfur, oxides, dirt, shaving particles, etc., The following tools are necessary to use R454B refrigerant.
Page 7: Cautions For Service
[1] Warning for service (1) Do not alter the unit. (2) For installation and relocation work, follow the instructions in the Installation Manual and use tools and pipe components specifically made for use with refrigerant specified in the outdoor unit installation manual. (3) Ask a dealer or an authorized technician to install, relocate and repair the unit.
Page 8: Additional Refrigerant Charge
[3] Additional refrigerant charge When charging directly from cylinder (1) Check that cylinder for R454B on the market is a siphon type. (2) Charging should be performed with the cylinder of siphon stood vertically. (Refrigerant is charged from liquid phase.) Unit Electronic weighing scale [4] Cautions for unit using R454B refrigerant...
Page 9 The following checks shall be applied to installations using flammable refrigerants: • The charge size is in accordance with the room size within which the refrigerant containing parts are installed. • The ventilation machinery and outlets are operating adequately and are not obstructed. •...
Page 10 (8) Charging Procedures In addition to conventional charging procedures, the following requirements shall be followed: • Ensure that contamination of different refrigerants does not occur when using charging equipment. Hoses or lines shall be as short as possible to minimize the amount of refrigerant contained in them. •...
Page 11: Service Tools
[5] Service tools (1) Use the below service tools as exclusive tools for R454B refrigerant. Tool name Specifications Gauge manifold ·Only for R454B ·Use the existing fitting specifications. (UNF1/2) ·Use high-tension side pressure of 768.7 PSIG [5.3 MPaG] or over. Charge hose ·Only for R454B ·Use pressure performance of 738.2 PSIG [5.09MPaG] or over.
Page 12 Tools for R454B (The following table shows whether conventional tools can be used or not.) Can R22 tools Can R407C tools Can R410A tools Tools and materials R454B tools be used? be used? be used? Gauge manifold Tool exclusive for R454B Air purge, refrigerant charge and operation check Charge hose...
Page 13 2-4. CHOOSING THE OUTDOOR UNIT INSTALLATION LOCATION R454B is heavier than air—as well as other refrigerants— so tends to accumulate at the base (in the vicinity of the floor). If R454B accumulates around base, it may reach a flammable concentration in case room is small. To avoid ignition, maintaining a safe work environment is required by ensuring appropriate ventilation.
Page 14 Refrigerant pipe airtight testing method (1) Connect the testing tools. Stop valve • Make sure the stop valves are closed and do not open them. Liquid Union pipe • Add pressure to the refrigerant lines through the service port Union of the stop valve for GAS.
Page 15 2-6. MINIMUM INSTALLATION AREA FOR INDOOR UNITS Install in a room with a floor area of A or more, corresponding to refrigerant quantity M (factory-charged refrigerant + locally added refrigerant). * For the factory-charged refrigerant amount, refer to the spec nameplate or installation manual. For the amount to be added locally, refer to the installation manual.
Page 16: Part Names And Functions
PART NAMES AND FUNCTIONS MXZ-2D20NL Air inlet (Back and side) Air outlet Drain outlet MXZ-3D24NL MXZ-4D30NL MXZ-2D20NLHZ Air inlet (Back and side) Air outlet Drain outlet MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ Air inlet (Back and side) Air outlet Drain outlet OBH949A...
Page 17: Specification
SPECIFICATION MXZ-2D20NL Outdoor model Item Indoor type Non-Duct (09+09) Duct (09+12) Cooling Btu/h 18,000 20,000 Capacity Heating 47 Btu/h 22,000 22,000 Heating 17 Btu/h 16,500 13,500 Cooling 1,384 2,000 Power Heating 47 1,641 1,771 consumption Heating 17 1,691 1,500 EER2 Cooling 13.00 10.00...
Page 18 MXZ-3D24NL Outdoor model Item Indoor type Non-Duct (06+09+09) Duct (12+12) Cooling Btu/h 22,000 23,600 Capacity Heating 47 Btu/h 25,000 25,400 Heating 17 Btu/h 15,500 16,000 Cooling 1,605 2,017 Power Heating 47 1,704 1,909 consumption Heating 17 1,465 1,711 EER2 Cooling 13.70 11.70 SEER2...
Page 19 MXZ-4D30NL Outdoor model Item Indoor type Non-Duct (06+06+09+09) Duct (18+18) Cooling Btu/h 28,600 27,400 Capacity Heating 47 Btu/h 28,600 27,600 Heating 17 Btu/h 18,200 17,800 Cooling 2,200 2,854 Power Heating 47 2,149 2,200 consumption Heating 17 1,667 1,837 EER2 Cooling 13.00 9.60 SEER2...
Page 20 MXZ-5D36NL Outdoor model Item Indoor type Non-Duct (06+06+06+09+09) Duct (18+18) Cooling Btu/h 35,400 33,400 Capacity Heating 47 Btu/h 36,000 34,400 Heating 17 Btu/h 23,000 22,400 Cooling 2,950 3,839 Power Heating 47 3,015 3,093 consumption Heating 17 2,407 2,626 EER2 Cooling 12.00 8.70 SEER2...
Page 21 MXZ-5D42NL Outdoor model Item Indoor type Non-Duct (06+09+09+09+09) Duct (24+24) Cooling Btu/h 40,500 36,400 Capacity Heating 47 Btu/h 45,000 41,000 Heating 17 Btu/h 29,000 23,000 Cooling 4,355 4,044 Power Heating 47 4,397 4,517 consumption Heating 17 3,295 3,548 EER2 Cooling 9.30 9.00 SEER2...
Page 22 MXZ-2D20NLHZ Outdoor model Item Indoor type Non-Duct (09+09) Duct (09+12) Cooling Btu/h 18,000 20,000 Capacity Heating 47 Btu/h 22,000 22,000 Heating 17 Btu/h 14,300 12,500 Cooling 1,333 1,802 Power Heating 47 1,612 1,688 consumption Heating 17 1,518 1,500 EER2 Cooling 13.50 11.10 SEER2...
Page 23 MXZ-3D24NLHZ Outdoor model Item Indoor type Non-Duct (06+09+09) Duct (12+12) Cooling Btu/h 22,000 23,600 Capacity Heating 47 Btu/h 25,000 24,600 Heating 17 Btu/h 15,400 15,000 Cooling 1,693 2,360 Power Heating 47 2,094 1,949 consumption Heating 17 1,590 1,954 EER2 Cooling 13.00 10.00 SEER2...
Page 24 MXZ-3D30NLHZ Outdoor model Item Indoor type Non-Duct (09+09+12) Duct (18+18) Cooling Btu/h 28,400 27,400 Capacity Heating 47 Btu/h 28,600 27,600 Heating 17 Btu/h 18,300 19,000 Cooling 2,470 2,660 Power Heating 47 2,395 2,285 consumption Heating 17 1,916 2,282 EER2 Cooling 11.50 10.3 SEER2...
Page 25: Noise Criteria Curves
NOISE CRITERIA CURVES MXZ-2D20NL MXZ-3D24NL FAN SPEED FUNCTION SPL(dB LINE FAN SPEED FUNCTION SPL(dB LINE High Cooling High Cooling High Heating High Heating NC-70 NC-70 NC-60 NC-60 NC-50 NC-50 NC-40 NC-40 NC-30 NC-30 APPROXIMATE APPROXIMATE THRESHOLD OF THRESHOLD OF NC-20 NC-20 HEARING FOR HEARING FOR...
Page 26 MXZ-5D42NL MXZ-2D20NLHZ FAN SPEED FUNCTION SPL(dB LINE FAN SPEED FUNCTION SPL(dB LINE High Cooling High Cooling High Heating High Heating NC-70 NC-70 NC-60 NC-60 NC-50 NC-50 NC-40 NC-40 NC-30 NC-30 APPROXIMATE APPROXIMATE THRESHOLD OF THRESHOLD OF NC-20 NC-20 HEARING FOR HEARING FOR CONTINUOUS CONTINUOUS...
Page 27: Outlines And Dimensions
OUTLINES AND DIMENSIONS MXZ-2D20NL Unit: inch (mm) 6-21/32” 19-11/16” 6-23/32” 2-9/16” 8-5/32” 12-3/8” Inlet Air Inlet 3-ø(1-5/16”) Drain hole Outlet 4-(13/32”×13/16”) Oval Hole (Foundation Bolt M8) Handle 13/32” 33-1/16” 1-3/16” 7-7/8” 1-1/32” 13” 1/2” Connecting wire hole 2-19/32” Connecting wire hole Unit B LIQ 1/4”(ø6.35)FLARE GAS 3/8”(ø9.52)FLARE...
Page 28 MXZ-3D24NL Unit: inch (mm) Conduit plate Conduit connector Lock nut Conduit plate OBH949A...
Page 29 MXZ-4D30NL Unit: inch (mm) Conduit plate Conduit connector Lock nut Conduit plate OBH949A...
Page 30 MXZ-5D36NL MXZ-5D42NL Unit: inch (mm) Conduit Conduit plate U connector Conduit panel Screws Conduit plate L Cable guide Lock nut OBH949A...
Page 31 MXZ-2D20NLHZ Unit: inch (mm) Conduit plate Conduit connector Lock nut Conduit plate OBH949A...
Page 32 MXZ-3D24NLHZ MXZ-3D30NLHZ Unit: inch (mm) Conduit Conduit plate U connector Conduit panel Screws Conduit plate L Cable guide Lock nut OBH949A...
Page 33: Wiring Diagram
WIRING DIAGRAM MXZ-2D20NL OBH949A...
Page 34 MXZ-3D24NL OBH949A...
Page 35 MXZ-4D30NL OBH949A...
Page 36 MXZ-5D36NL MXZ-5D42NL OBH949A...
Page 37 MXZ-2D20NLHZ OBH949A...
Page 38 MXZ-3D24NLHZ MXZ-3D30NLHZ OBH949A...
Page 39: Refrigerant System Diagram
REFRIGERANT SYSTEM DIAGRAM MXZ-2D20NL Unit: inch (mm) Service port R.V.coil Refrigerant flow in cooling Compressor Refrigerant flow in heating Fusible Plug Discharge Service port temperature thermistor RT62 Muffler Accumulator Union 4-way ø3/8 valve High pressure switch Room A Room B Stop Valve ø3/8 (with service...
Page 40: Operating Range
MXZ-2D20NL Operating Range Indoor air intake temperature Outdoor air intake temperature Maximum 95°FDB, 71°FWB 115°FDB Cooling Minimum 67°FDB, 57°FWB 14°FDB Maximum 80°FDB, 67°FWB 75°FDB Heating Minimum 70°FDB, 60°FWB 5°FWB MAX. REFRIGERANT PIPING LENGTH & PIPE SIZE SELECTION Piping length each indoor unit (a, b) 82 ft.
Page 41 MXZ-3D24NL Unit: inch (mm) R.V.coil Fusible Plug Refrigerant flow in heating Refrigerant flow in cooling Compressor Service port Discharge High Pressure Switch temperature Muffler thermistor RT62 Service port Accumulator Header(Gas) Union ø1/2 4-way Room A valve muffler ø3/8 Room B Stop valve Header (Evaporator) ø3/8...
Page 42 MXZ-3D24NL Operating Range Indoor air intake temperature Outdoor air intake temperature Maximum 95°FDB, 71°FWB 115°FDB Cooling Minimum 67°FDB, 57°FWB 14°FDB Maximum 80°FDB, 67°FWB 75°FDB, 65°FWB Heating Minimum 70°FDB, 60°FWB 6°FDB, 5°FWB MAX. REFRIGERANT PIPING LENGTH & PIPE SIZE SELECTION Piping length each indoor unit (a, b, c) 82 ft.
Page 43 MXZ-4D30NL Unit: inch (mm) R.V.coil Fusible Plug Refrigerant flow in heating Refrigerant flow in cooling Compressor Service port Discharge High Pressure Switch temperature Muffler thermistor RT62 Service port Accumulator Header(Gas) Union ø1/2 4-way Room A valve muffler ø3/8 Room B Stop valve Header (Evaporator) ø3/8...
Page 44 MXZ-4D30NL Operating Range Indoor air intake temperature Outdoor air intake temperature Maximum 95°FDB, 71°FWB 115°FDB Cooling Minimum 67°FDB, 57°FWB 14°FDB Maximum 80°FDB, 67°FWB 75°FDB, 65°FWB Heating Minimum 70°FDB, 60°FWB 6°FDB, 5°FWB MAX. REFRIGERANT PIPING LENGTH & PIPE SIZE SELECTION Piping length each indoor unit (a, b, c, d) 82 ft.
Page 45 MXZ-5D36NL MXZ-5D42NL Unit: inch (mm) R.V.coil Refrigerant flow in heating Compressor Refrigerant flow in cooling Fusible Plug Discharge High Pressure Switch Service port temperature Muffler thermistor RT62 Union Header (Gas) Oil Separator ø1/2 Strainer Room A 4-way Accumulator Service port ø3/8 Room B valve...
Page 46 MXZ-5D36NL MXZ-5D42NL Operating Range Indoor air intake temperature Outdoor air intake temperature Maximum 95°FDB, 71°FWB 115°FDB Cooling Minimum 67°FDB, 57°FWB 14°FDB Maximum 80°FDB, 67°FWB 75°FDB, 65°FWB Heating Minimum 70°FDB, 60°FWB 6°FDB, 5°FWB MAX. REFRIGERANT PIPING LENGTH & PIPE SIZE SELECTION MXZ-5D36NL Piping length each indoor unit (a, b, c, d, e) 82 ft.
Page 47 MXZ-2D20NLHZ Unit: inch (mm) R.V.coil Fusible Plug Refrigerant flow in heating Refrigerant flow in cooling Compressor Service port Discharge High Pressure Switch temperature Muffler thermistor RT62 Service port Accumulator Header(Gas) Union ø3/8 4-way Room A valve muffler ø3/8 Room B Stop valve Header (Evaporator) (with service port)
Page 48 MXZ-2D20NLHZ Operating Range Indoor air intake temperature Outdoor air intake temperature Maximum 95°FDB, 71°FWB 115°FDB Cooling Minimum 67°FDB, 57°FWB 14°FDB Maximum 80°FDB, 67°FWB 75°FDB, 65°FWB Heating Minimum 70°FDB, 60°FWB -12°FDB, -13°FWB MAX. REFRIGERANT PIPING LENGTH & PIPE SIZE SELECTION Piping length each indoor unit (a, b) 82 ft.
Page 49 MXZ-3D24NLHZ MXZ-3D30NLHZ R.V.coil Refrigerant flow in heating Compressor Refrigerant flow in cooling Fusible Plug Discharge High Pressure Switch Service port temperature Muffler thermistor RT62 Oil Separator Strainer Header (Gas) 4-way Accumulator Union Service port valve ø1/2 Room A muffler ø3/8 Room B Stop valve ø3/8...
Page 50 MXZ-3D24NLHZ MXZ-3D30NLHZ Operating Range Indoor air intake temperature Outdoor air intake temperature Maximum 95°FDB, 71°FWB 115°FDB Cooling Minimum 67°FDB, 57°FWB 14°FDB Maximum 80°FDB, 67°FWB 75°FDB, 65°FWB Heating Minimum 70°FDB, 60°FWB -12°FDB, -13°FWB MAX. REFRIGERANT PIPING LENGTH & PIPE SIZE SELECTION Piping length each indoor unit (a, b, c) 82 ft.
Page 51: Pumping Down
PUMPING DOWN When relocating or disposing of the air conditioner, pump down the system following the procedure below so that no refrigerant is released into the atmosphere. (1) Turn off the breaker. (2) Connect the gauge manifold valve to the service port of the stop valve on the gas pipe side of the outdoor unit. (3) Fully close the stop valve on the liquid pipe side of the outdoor unit.
Page 52: Data
DATA MXZ-2D20NL Model Indoor type Non-Duct (09+09) Duct (09+12) Item Unit Cooling Heating Cooling Heating Total Capacity Btu/h 18,000 22,000 20,000 22,000 – – – – – Input 1.384 1.641 2.000 1.771 Electrical Power supply (V, phase, Hz) 208/230, 1, 60 circuit Input 1.335...
Page 53 MXZ-4D30NL Model Indoor type Non-Duct (06+06+09+09) Duct (18+18) Item Unit Cooling Heating Cooling Heating Total Capacity Btu/h 28,600 28,600 27,400 27,600 – – – – – Input 2.200 2.149 2.854 2.200 Electrical Power supply (V, phase, Hz) 208/230, 1, 60 circuit Input 2.190...
Page 54 MXZ-5D42NL Model Indoor type Non-Duct (06+09+09+09+09) Duct (24+24) Item Unit Cooling Heating Cooling Heating Total Capacity Btu/h 40,500 45,000 36,400 41,000 – – – – – Input 4.355 4.397 4.045 4.518 Electrical Power supply (V, phase, Hz) 208/230, 1, 60 circuit Input 4.112...
Page 55 MXZ-3D24NLHZ Model Indoor type Non-Duct (06+06+09) Duct (12+12) Item Unit Cooling Heating Cooling Heating Total Capacity Btu/h 22,000 25,000 23,600 24,600 – Input 1.693 2.094 2.360 2.185 Electrical Power supply (V, phase, Hz) 208/230, 1, 60 circuit Input 1.501 1.658 2.341 2.172 Comp.
Page 56 9-1. OPERATING RANGE (1) POWER SUPPLY Model Rating Guaranteed Voltage MXZ-2D20NL MXZ-2D20NLHZ MXZ-3D24NL MXZ-3D24NLHZ Min. 198 V 208 V 230 V Max. 253 V MXZ-4D30NL MXZ-3D30NLHZ Outdoor unit 208/230 V 60 Hz 1ø MXZ-5D36NL MXZ-5D42NL (2) OPERATION Intake air Indoor Outdoor temperature Function...
Page 57: Indoor Unit
MXZ-2D20NL MXZ-3D24NL MXZ-4D30NL MXZ-5D36NL MXZ-5D42NL MXZ-2D20NLHZ MXZ-3D24NLHZ MXZ-3D30NLHZ The standard specifications apply only to the operation of the air conditioner under normal conditions. Since operating conditions vary according to the areas where these units are installed, the following information has been pro- vided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.
Page 58 9-2. CAPACITY AND THE INPUT CURVES MXZ-2D20NL Cooling capacity 10.2 10.4 Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Total input (Cooling) Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Heating capacity 20.0 29.5 38.7...
Page 59 MXZ-3D24NL MXZ-4D30NL MXZ-5D36NL MXZ-5D42NL Cooling capacity 10.2 10.4 12.1 13.4 11.1 12.2 10.1 11.1 10.0 Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Total input (Cooling) Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Heating capacity 20.0 29.5...
Page 60 MXZ-2D20NLHZ Cooling capacity 10.2 10.4 Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Total input (Cooling) Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Heating capacity 20.0 29.5 38.7 48.4 18.5 27.5 36.0 45.0 17.1...
Page 61 MXZ-3D24NLHZ MXZ-3D30NLHZ Cooling capacity 10.2 10.4 12.1 13.4 11.1 12.2 10.1 11.1 10.0 Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Total input (Cooling) Indoor intake air Wet-bulb temperature (°F) Outdoor intake air Dry-bulb temperature (°F) Heating capacity 20.0 29.5...
Page 62 9-3. CAPACITY AND INPUT CORRECTION BY MEANS OF INVERTER OUTPUT FREQUENCY (OUTDOOR UNIT: MXZ-2D20NL) 1. 06-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity <HEAT>Total input Frequency Frequency Frequency Frequency 2. 09-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity <HEAT>Total input Frequency Frequency...
Page 63 (OUTDOOR UNIT: MXZ-3D24NL MXZ-4D30NL MXZ-2D20NLHZ) 1. 06-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity <HEAT>Total input Frequency Frequency Frequency Frequency 2. 09-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity <HEAT>Total input Frequency Frequency Frequency Frequency 3. 12-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity...
Page 64 (OUTDOOR UNIT: MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ) 1. 06-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity <HEAT>Total input Frequency Frequency Frequency Frequency 2. 09-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity <HEAT>Total input Frequency Frequency Frequency Frequency 3. 12-class unit in single operation <COOL>Capacity <COOL>Total input <HEAT>Capacity...
Page 65 9-4. OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT 1. 06-class unit in single operation (OUTDOOR UNIT: MXZ-2D20NL) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 66 2. 09-class unit in single operation (OUTDOOR UNIT: MXZ-2D20NL) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 67 3. 12-class unit in single operation (OUTDOOR UNIT: MXZ-2D20NL) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 68 4. 15-class unit in single operation (OUTDOOR UNIT: MXZ-2D20NL) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 69 5. 06-class unit in single operation (OUTDOOR UNIT: MXZ-3D24NL MXZ-4D30NL MXZ-2D20NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 70 6. 09-class unit in single operation ( OUTDOOR UNIT: MXZ-3D24NL MXZ-4D30NL MXZ-2D20NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 71 7. 12-class unit in single operation ( OUTDOOR UNIT: MXZ-3D24NL MXZ-4D30NL MXZ-2D20NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 72 8. 15-class unit in single operation ( OUTDOOR UNIT: MXZ-3D24NL MXZ-4D30NL MXZ-2D20NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 73 9. 18-class unit in single operation ( OUTDOOR UNIT: MXZ-3D24NL MXZ-4D30NL) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 74 10. 24-class unit in single operation ( OUTDOOR UNIT: MXZ-4D30NL) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 75 11. 06-class unit in single operation (OUTDOOR UNIT: MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 76 12. 09-class unit in single operation (OUTDOOR UNIT: MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 77 13. 12-class unit in single operation (OUTDOOR UNIT: MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 78 14. 15-class unit in single operation (OUTDOOR UNIT: MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 79 15. 18-class unit in single operation (OUTDOOR UNIT: MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 80 16. 24-class unit in single operation (OUTDOOR UNIT: MXZ-5D36NL MXZ-5D42NL MXZ-3D30NLHZ) (1) COOL operation Data is based on the condition of indoor humidity <How to work fixed-frequency operation> 1. Set emergency switch to COOL or HEAT. The switch is located Air flow speed: High on indoor unit.
Page 81: Actuator Control
ACTUATOR CONTROL MXZ-2D20NL MXZ-3D24NL MXZ-4D30NL MXZ-5D36NL MXZ-5D42NL MXZ-2D20NLHZ MXZ-3D24NLHZ MXZ-3D30NLHZ Relation between main sensor and actuator Actuator 2-way solenoid Defrost heater valve Sensor Purpose Outdoor fan MXZ-5D36NL MXZ-2D20NLHZ Compressor 4-way valve motor MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D24NLHZ MXZ-3D30NLHZ MXZ-3D30NLHZ ○ ○ Discharge temperature Protection thermistor ○...
Page 82: Service Functions
SERVICE FUNCTIONS MXZ-2D20NL MXZ-3D24NL MXZ-4D30NL MXZ-5D36NL MXZ-5D42NL MXZ-2D20NLHZ MXZ-3D24NLHZ MXZ-3D30NLHZ 11-1. PRE-HEAT CONTROL If moisture gets into the refrigerant cycle, or when refrigerant is liquefied and collected in the compressor, it may interfere the startup of the compressor. To improve start-up condition, the compressor is energized even while it is not operating. This is to generate heat at the winding.
Page 83 11-2. AUTO LINE CORRECTING Outdoor unit has an auto line correcting function which automatically detects and corrects improper wiring or piping. Improper wiring or piping can be automatically detected by pressing the piping/wiring correction switch (SW871). When improper wiring or piping is detected, wiring lines are corrected. This will be completed in about 10 to 20 minutes.
Page 84 11-3. CHANGING THE SET REFRIGERANT EVAPORATING TEMPERATURE NOTE: If you lower the refrigerant evaporating temperature with the windows open, it may cause condensation to form. [How to change the refrigerant evaporating temperature] (1) Make sure there is no possibility of causing condensation to form before making the setting. (2) Make the setting referring to the table below.
Page 85: Troubleshooting
TROUBLESHOOTING MXZ-2D20NL MXZ-3D24NL MXZ-4D30NL MXZ-5D36NL MXZ-5D42NL MXZ-2D20NLHZ MXZ-3D24NLHZ MXZ-3D30NLHZ 12-1. CAUTIONS ON TROUBLESHOOTING 1. Before troubleshooting, check the following: 1) Check the power supply voltage. 2) Check the indoor/outdoor connecting wire for miswiring. 2. Take care of the following during servicing. 1) Before servicing the air conditioner, be sure to turn OFF the unit first with the remote controller, and then after confirm- ing the horizontal vane is closed, turn OFF the breaker and/or disconnect the power plug.
Page 86: Operational Procedure
2. Flow chart of the detailed outdoor unit failure mode recall function Operational procedure The outdoor unit might be abnormal. Check if outdoor unit is abnormal according to the following procedures. *1 Regardless of normal or abnormal condition, 2 short Make sure that the remote controller is set to the failure mode recall function.
Page 87 NOTE: Blinking patterns of this mode differ from the ones of 3. Table of outdoor unit failure mode recall function TROUBLESHOOTING CHECK TABLE (12-4.). LED indication The left lamp of Indoor/outdoor (Outdoor P.C. OPERATION Abnormal point unit failure Condition Remedy board) INDICATOR lamp (Failure mode/protection)
Page 88 NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (12-4.). LED indication The left lamp of Indoor/outdoor (Outdoor P.C. OPERATION Abnormal point unit failure Condition Remedy board) INDICATOR lamp (Failure mode/protection) mode recall (Indoor unit) function LED 1 LED 2...
Page 89: Instructions For Troubleshooting
12-3. INSTRUCTIONS FOR TROUBLESHOOTING • Check the indoor unit while referring to the indoor unit service manual, and confirm if there is any problem in the indoor unit. Then, check the outdoor unit while referring to this page. Operation start Check the outdoor unit LED indicator.
Page 90 12-4. TROUBLESHOOTING CHECK TABLE Indication Abnormal point / Symptom Condition Remedy Condition LED1(Red) LED2(Yellow) Outdoor The indoor unit detects an abnormality in the LEV • Refer to 12-6. “Check of LEV”. Once LEV and drain pump unit does and drain pump. •...
Page 91 Indication Abnormal point / Symptom Condition Remedy Condition LED1(Red) LED2(Yellow) 18 ‘Outdoor • Reconnect compressor connector. Overcurrent is detected after 30 seconds of com- IPM protection unit stops • Refer to 12-6. “How to check inverter/ pressor startup. and restarts compressor”.
Page 92 Indication Abnormal point / Symptom Condition Remedy Condition LED1(Red) LED2(Yellow) 34 Outdoor The frequency of the compressor is kept 80 Hz or Low discharge • Refer to 12-6. “Check of LEV”. unit more and the discharge temperature is kept under 4 times temperature •...
Page 93 12-5. TROUBLESHOOTING CRITERION OF MAIN PARTS MXZ-2D20NL MXZ-3D24NL MXZ-4D30NL MXZ-5D36NL MXZ-5D42NL MXZ-2D20NLHZ MXZ-3D24NLHZ MXZ-3D30NLHZ Part name Check method and criterion Defrost thermistor (RT61) Measure the resistance with a multimeter. Fin temperature thermistor (RT64) Refer to 12-7. “TEST POINT DIAGRAM AND VOLTAGE”, 1. “Outdoor control P.C.board”, Ambient temperature thermistor 2.
Page 94: Troubleshooting Flow
12-6. TROUBLESHOOTING FLOW Outdoor unit does not operate. Check of power supply Check the main power supply circuit for proper connections. Turn ON the power supply. Is there voltage of 208/230 V AC in the Check the power supply cable. power supply terminal block? Is the output voltage from the outdoor Replace the outdoor control P.C.
Page 95 • When unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch. Indoor unit does not operate. • When OPERATION INDICATOR lamp blinks ON and OFF in every 0.5-second. Outdoor unit does not operate. How to check miswiring and serial signal error (when outdoor unit does not work) Turn OFF the power supply.
Page 96 The cooling operation or heating operation does not operate. Check of R.V. coil • When cooling operation does not work, CNAC Outdoor control CN712 P.C. board 1. Disconnect the lead wire leading to the compressor. 2. 3 minutes after turning ON the power supply, start EMERGENCY Outdoor power CNAC2 OPERATION in COOL mode.
Page 97 • When cooling, heat exchanger of non-operating indoor unit frosts. • When heating, non-operating indoor unit gets warm. Check of LEV CN791 Turn ON the power supply to the outdoor unit after checking LEV coil is CN792 Outdoor mounted to the LEV body securely. CN793 control CN794...
Page 98 • When heating, room does not get warm. • When cooling, room does not get cool. How to check inverter/compressor Disconnect the terminal of the compressor or the connector (CNMC) between the compressor and the outdoor power P.C. board. 3 minutes after the power supply is turned ON, start EMERGENCY OPERATION.
Page 99 • When thermistor is abnormal, Check of outdoor thermistors Thermistor Symbol Connector, Pin No. Board Defrost RT61 Between CNTH1 pin1 and pin2 Discharge temperature RT62 Between CNTH1 pin3 and pin4 Outdoor control P.C. board Outdoor heat exchanger temperature RT68 Between CNTH1 pin7 and pin8 Ambient temperature RT65 Between CNTH2 pin1 and pin2...
Page 100 • Fan motor does not operate or stops operating shortly after starting the operation. Check of outdoor fan motor CNF1 Outdoor control Disconnect CNF1 and measure the resistance of the outdoor fan motor. P.C. board Model name of fan motor: Is the resistance of outdoor fan motor Replace the outdoor fan motor.
Page 101 • When the operation frequency does not go up from the lowest frequency. Outdoor control Check of HPS CN63H P.C. board 1. Disconnect the connector CN63H on the outdoor control P.C. board. 2. Disconnect the connector connecting HPS and the thermal protector. 3.
Page 102 Check of thermal protector 1. Disconnect the connector CN63H on the outdoor control P.C. board. 2. Disconnect the connector connecting HPS and the thermal protector, and then check the conduction of the thermal protector. Is the thermal protector Thermal protector is normal. conductive? Take a time until the Thermal protector to be ordinary temperature.
Page 103 12-7. TEST POINT DIAGRAM AND VOLTAGE Discharge temperature thermistor (RT62) Defrost thermistor (RT61) Ambient temperature thermistor (RT65) 1. Outdoor control P.C. board Outdoor heat exchanger temperature thermistor (RT68) MXZ-2D20NL 100 110 120 (ºC) 104 122 140 158 176 194 212 230 248 (ºF) Temperature Thermistor R100 = 13.36 kΩ...
Page 104 1. Outdoor control P.C. board Discharge temperature thermistor (RT62) Defrost thermistor (RT61) Ambient temperature thermistor (RT65) MXZ-3D24NL MXZ-2D20NLHZ Outdoor heat exchanger temperature thermistor (RT68) MXZ-4D30NL MXZ-3D24NLHZ MXZ-5D36NL MXZ-3D30NLHZ MXZ-5D42NL 100 110 120 (ºC) 104 122 140 158 176 194 212 230 248 (ºF) Temperature Thermistor R100 = 13.36 kΩ...
Page 105 2. Outdoor power P.C. board MXZ-2D20NL CN171 Fin temperature thermistor (RT64) Output to drive compressor CN152 Signal Transmission (From Outdoor Control P.C. board) 5 V DC pulse wave Connect to earth F1 FUSE 10A 250V F2 FUSE 10A 250V CNAC1 208/230 V AC Output Connect to earth...
Page 106 2. Outdoor power P.C. board MXZ-3D24NL MXZ-2D20NLHZ MXZ-4D30NL MXZ-3D24NLHZ MXZ-5D36NL MXZ-3D30NLHZ MXZ-5D42NL CNDC CNAC1 Output to drive compressor Bus-bar voltage 208/230 V AC 290 - 370 V DC Output Connect to earth F2 FUSE 10A 250V F1 FUSE 10A 250V Connect to earth 208/230 V AC Input...
Page 107: Disassembly Instructions
DISASSEMBLY INSTRUCTIONS <Detaching method of the terminal with locking mechanism> The terminal which has the locking mechanism can be detached as shown below. There are 2 types of the terminal with locking mechanism. The terminal without locking mechanism can be detached by pulling it out. Check the shape of the terminal before detaching.
Page 108 OPERATING PROCEDURE PHOTOS/FIGURES Photo 4 2. Removing the outdoor control P.C. board, the outdoor power P.C. board and the reactor Electrical box (1) Remove the service panel (Photo 1). assembly (2) Disconnect the power supply cord and indoor/outdoor connecting wires. (3) Remove the top panel, the cabinet, and the back panel (Photo 1, 2, 3).
Page 109 OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing the fan motor Photo 8 Screws of the outdoor fan motor (1) Remove the service panel (Photo 1). (2) Disconnect the power supply cord and indoor/outdoor Sound connecting wires. proof (3) Remove the top panel, the cabinet, and the back panel felt (Photo 1, 2, 3).
Page 110 OPERATING PROCEDURE PHOTOS/FIGURES Photo 9 4. Removing the compressor and the 4-way valve R.V. coil 4-way valve (1) Remove the service panel (Photo 1). (2) Disconnect the power supply cord and indoor/outdoor connecting wires. (3) Remove the top panel, the cabinet, and the back panel Discharge pipe (Photo 1, 2, 3).
Page 111 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing the expansion valve Photo 11 NOTE: Gas recovery is not required if the unit is pumped down. (1) Remove the top panel and the service panel (Refer to section 1). (2) Disconnect the power supply cord and indoor/outdoor connecting wires.
Page 112 13-2. MXZ-3D24NL MXZ-4D30NL MXZ-2D20NLHZ NOTE: Turn OFF the power supply before disassembly. Photos: MXZ-4D30NL OPERATING PROCEDURE PHOTOS/FIGURES Photo 1 Screws of the top panel 1. Removing the panels (1) Remove all the screws fixing the top panel, and remove the top panel. (2) Remove all the screws fixing the service panel.
Page 113 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the outdoor control P.C. board, the Photo 6 reactor, the outdoor power P.C. board, and the heatsink (1) Remove the top panel and the service panel (Refer to section 1). (2) Disconnect the power supply cord and indoor/outdoor Catches of the connecting wires.
Page 114 OPERATING PROCEDURE PHOTOS/FIGURES (14) Disengage all the catches of the PB cover, and remove Photo 9 the PB cover (Photo 9). (15) Remove the screw fixing the outdoor power P.C. board and all the screws fixing the outdoor power P.C. board and the heatsink (Photo 10).
Page 115 OPERATING PROCEDURE PHOTOS/FIGURES Photo 12 Photo 13 Screws of fixing parts of the heat sink Notch Lead wires of Lead wire of compressor CN171 Photo 14 3. Removing the fan motor Propeller fan (1) Remove the top panel, the service panel, and the front panel (Refer to section 1).
Page 116 OPERATING PROCEDURE PHOTOS/FIGURES Photo 15 4. Removing the fusible plug (the 4-way valve assembly) (1) Remove the top panel, the service panel, and the front panel (Refer to section 1). (2) Disconnect the power supply cord and indoor/outdoor connecting wires, and remove the back panel. (3) Recover gas from the refrigerant circuit.
Page 117 OPERATING PROCEDURE PHOTOS/FIGURES Photo 18 5. Removing the compressor and 4-way valve (1) Remove the top panel, the service panel, and the front panel (Refer to section 1). (2) Disconnect the power supply cord and indoor/outdoor connecting wires, and remove the back panel. (3) Recover gas from the refrigerant circuit.
Page 118 13-3. MXZ-5D36NL MXZ-5D42NL MXZ-3D24NLHZ MXZ-3D30NLHZ NOTE: Turn OFF the power supply before disassembly. Photos: MXZ-5D36NL OPERATING PROCEDURE PHOTOS/FIGURES Photo 3 1. Removing the panels Catch of the front panel Catch of the front panel (1) Remove all the screws fixing the top panel, and remove Screws of the front panel the top panel.
Page 119 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the outdoor control P.C. board, the reactor, Photo 8 the outdoor power P.C. board, and the heatsink (1) Remove the top panel, the service panel, conduit panel and cable guide (Refer to section 1). (2) Disconnect the power supply cord and indoor/outdoor connecting wires.
Page 120 OPERATING PROCEDURE PHOTOS/FIGURES (14) Disengage all the catches of the PB cover, and remove Photo 10 the PB cover (Photo 10). (15) Remove the screw fixing the outdoor power P.C. board and all the screws fixing the outdoor power P.C. board and the heatsink (Photo 11).
Page 121: Removing The Fan Motor
OPERATING PROCEDURE PHOTOS/FIGURES Photo 13 Photo 14 Notch Lead wires of Lead wire of Screws of fixing parts of the heat sink compressor CN171 Photo 15 3. Removing the fan motor Propeller fan (1) Remove the top panel, the service panel, conduit panel and cable guide (Refer to section 1).
Page 122 OPERATING PROCEDURE PHOTOS/FIGURES 4. Removing the fusible plug (the 4-way valve Photo 16 assembly) (1) Remove the top panel, the service panel, conduit panel and cable guide (Refer to section 1). (2) Disconnect the power supply cord and indoor/outdoor connecting wires, and remove the back panel. (3) Recover gas from the refrigerant circuit.
Page 123 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing the compressor and 4-way valve Photo 19 (1) Remove the top panel, the service panel, conduit panel and cable guide (Refer to section 1). (2) Disconnect the power supply cord and indoor/outdoor connecting wires, and remove the back panel. (3) Recover gas from the refrigerant circuit.
Page 124 HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN © Copyright 2024 MITSUBISHI ELECTRIC CORPORATION Issued: Nov. 2024. No. OBH949 REVISED EDITION-A Published: Aug. 2024. No. OBH949 Made in Japan Specifications are subject to change without notice.

Mitsubishi Electric MSZ-FX NL Series Service Manual

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