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Mitsubishi Electric SEZ Series Service Manual
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Mitsubishi Electric SEZ Series Service Manual

Mitsubishi Electric SEZ Series Service Manual

Split-type, heat pump air conditioners
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2024
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
SERVICE MANUAL
Series SEZ
Model name
<Indoor unit>
SEZ-AD09NL
SEZ-AD12NL
SEZ-AD15NL
SEZ-AD18NL
INDOOR UNIT

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Summary of Contents for Mitsubishi Electric SEZ Series

  • Page 1 2024 SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS SERVICE MANUAL Series SEZ Model name <Indoor unit> SEZ-AD09NL SEZ-AD12NL SEZ-AD15NL SEZ-AD18NL INDOOR UNIT...
  • Page 2 CONTENTS 1. SAFETY PRECAUTION ··········································································· 3 2. PART NAMES AND FUNCTIONS ······························································ 8 3. SPECIFICATION ···················································································· 9 4. FAN PERFORMANCE AND CORRECTED AIR FLOW ································· 11 5. SOUND PRESSURE LEVELS ·································································15 6. OUTLINES & DIMENSIONS ····································································18 7. WIRING DIAGRAM ················································································20 8.
  • Page 3 SAFETY PRECAUTION 1. SAFETY PRECAUTION MEANINGS OF SYMBOLS DISPLAYED ON THE UNIT Refrigerant This unit uses flammable refrigerant. Safety Group WARNING If refrigerant leaks and comes in contact with fire or heating part, it will create (Risk of fire) harmful gas and there is risk of fire. Read the OPERATION MANUAL carefully before operation.
  • Page 4 SAFETY PRECAUTION <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 5 SAFETY PRECAUTION <3> Additional refrigerant charge When charging directly from cylinder • Check that cylinder for R454B on the market is syphon type. • Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.) <4>...
  • Page 6 SAFETY PRECAUTION or fans. (5) Detection of flammable refrigerants Under no circumstances shall potential sources of ignition be used in the searching for or detection of refrigerant leaks. A halide torch (or any other detector using a naked flame) shall not be used. The following leak detection methods are deemed acceptable for all refrigerant systems.
  • Page 7 SAFETY PRECAUTION are labels on the equipment stating the equipment contains FLAMMABLE REFRIGERANT. (10) Recovery When removing refrigerant from a system, either for servicing or decommissioning, it is recommended good practice that all refrigerants are removed safely. When transferring refrigerant into cylinders, ensure that only appropriate refrigerant recovery cylinders are employed. Ensure that the correct number of cylinders for holding the total system charge is available.
  • Page 8 PART NAMES AND FUNCTIONS 2. PART NAMES AND FUNCTIONS • Indoor Unit Air intake (sucks the air inside the room into the unit) Air outlet HWE24090...
  • Page 9 SPECIFICATION 3. SPECIFICATION Service Ref. SEZ-AD09NL Power supply (phase, cycle, voltage) 1 phase, 60Hz, 208/230V Max. Fuse Size Min. Circuit Ampacity 0.95 External finish Galvanized sheets Heat exchanger Plate fin coil Fan (drive) × No. Sirocco fan × 2 Fan motor output 0.096 Fan motor F.L.A...
  • Page 10 SPECIFICATION Service Ref. SEZ-AD15NL Power supply (phase, cycle, voltage) 1 phase, 60Hz, 208/230V Max. Fuse Size Min. Circuit Ampacity 1.35 External finish Galvanized sheets Heat exchanger Plate fin coil Fan (drive) × No. Sirocco fan × 3 Fan motor output 0.096 Fan motor F.L.A...
  • Page 11 FAN PERFORMANCE AND CORRECTED AIR FLOW 4. FAN PERFORMANCE AND CORRECTED AIR FLOW SEZ-AD09NL SEZ-AD09NL (External static pressure 0.02[in.WG](5Pa)) 208/230V 60Hz (External static pressure 0.06[in.WG](15Pa)) 208/230V 60Hz [0.16] [0.20] Limit Limit [0.16] [0.12] High [0.12] [0.08] [0.08] Middle High Rated point [0.04] Middle [0.04]...
  • Page 12 FAN PERFORMANCE AND CORRECTED AIR FLOW SEZ-AD12NL SEZ-AD12NL (External static pressure 0.06[in.WG](15Pa)) 208/230V 60Hz (External static pressure 0.02[in.WG](5Pa)) 208/230V 60Hz [0.20] [0.16] [0.16] [0.12] Limit [0.12] Limit [0.08] High [0.08] High Middle Rated point [0.04] Middle [0.04] Rated point [212] [247] [282] [318]...
  • Page 13 FAN PERFORMANCE AND CORRECTED AIR FLOW SEZ-AD15NL SEZ-AD15NL (External static pressure 0.02[in.WG](5Pa)) 208/230V 60Hz (External static pressure 0.06[in.WG](15Pa)) 208/230V 60Hz [0.16] [0.20] Limit Limit [0.16] [0.12] High [0.12] [0.08] High Middle [0.08] Middle Rated point [0.04] [0.04] Rated point [282] [318] [353] [388]...
  • Page 14 FAN PERFORMANCE AND CORRECTED AIR FLOW SEZ-AD18NL SEZ-AD18NL (External static pressure 0.02[in.WG](5Pa)) 208/230V 60Hz (External static pressure 0.06[in.WG](15Pa)) 208/230V 60Hz [0.16] [0.20] Limit Limit [0.16] [0.12] High [0.12] Middle [0.08] High [0.08] Middle Rated point [0.04] [0.04] Rated point [318] [353] [388] [424] [459] [494]...
  • Page 15 SOUND PRESSURE LEVELS 5. SOUND PRESSURE LEVELS 5-1. Sound pressure level Ceiling concealed Aux. duct test unit Measurement location 5-2. NC curves SEZ-AD09NL External Static Pressure: 5Pa [0.02in.WG] External Static Pressure: 15Pa [0.06in.WG] Power Source: 208-230V Power Source: 208-230V 70.0 70.0 High 60Hz...
  • Page 16 SOUND PRESSURE LEVELS SEZ-AD12NL External Static Pressure: 5Pa [0.02in.WG] External Static Pressure: 15Pa [0.06in.WG] Power Source: 208-230V Power Source: 208-230V 70.0 70.0 High 60Hz High 60Hz Middle 60Hz Middle 60Hz 65.0 65.0 60Hz 60Hz 60.0 60.0 55.0 55.0 50.0 50.0 45.0 45.0 40.0...
  • Page 17 SOUND PRESSURE LEVELS External Static Pressure: 35Pa [0.14in.WG] External Static Pressure: 50Pa [0.20in.WG] Power Source: 208-230V Power Source: 208-230V 70.0 70.0 High 60Hz High 60Hz Middle 60Hz Middle 60Hz 65.0 65.0 60Hz 60Hz 60.0 60.0 55.0 55.0 50.0 50.0 45.0 45.0 40.0 40.0...
  • Page 18 OUTLINES & DIMENSIONS 6. OUTLINES & DIMENSIONS INDOOR UNIT SEZ-AD09, 12, 15,18NL HWE24090...
  • Page 19 OUTLINES & DIMENSIONS HWE24090...
  • Page 20 WIRING DIAGRAM 7. WIRING DIAGRAM SEZ-AD09, 12, 15,18NL HWE24090...
  • Page 21 REFRIGERANT SYSTEM DIAGRAM 8. REFRIGERANT SYSTEM DIAGRAM SEZ-AD09, 12, 15, 18NL Strainer (#50) Heat exchanger Refrigerant GAS pipe connection (Flare) Thermistor TH5 (Cond./ Eva.temperature) Refrigerant flow in cooling Refrigerant flow in heating Refrigerant LIQUID pipe connection (Flare) Thermistor TH2 Pipe temperature(Liquid) Thermistor TH1 (Room temperature) Strainer (#50)
  • Page 22 Failure to install and maintain such temperature control mechanism may void the warranty for this unit. • Mitsubishi Electric shall not bear any warranty obligation or other liability for any damage or loss in connection with such third party auxiliary heaters.
  • Page 23 HEATER CONTROL • Table 2 shows how the field-installed heater is controlled. Table. 2 [Heater Control Table] Mode Condition Change T RA has not (To -T RA ) > increased by EH1 ON 2.7 ° F [1.5 °C] 0.9 °F [0.5°C] in X min T RA has not (To -T RA ) >...
  • Page 24 HEATER CONTROL • Chart 1 and Table 4 show an example of heater operation. Chart 1 [Heater Operation Example] T  - 0.9 °F [0.5 °C] T - 2.7 °F [1.5 °C] > 8 X min X min X min Table. 4 [Heater Operation Example] Step Condition Result...
  • Page 25 HEATER CONTROL 9-3. FAN CONTROL By setting the Mode No. 11 in the Function Table in section 9-2 and using fan control connector on the optional parts PAC-YU25HT, the following patterns of fan control will become possible when [DEFROST] or [ERROR] is displayed. Fan control patterns when [DEFROST] or [ERROR] is displayed Heater is installed in the duct.
  • Page 26 HEATER CONTROL (3) Locally procured wiring ♦A basic connection method is shown below. Indoor unit Remote control board Relay circuit control board Adapter CN24/CN24A (1st) (2nd) White CN2Y White Electric Heater or panel heater (applicable only when a panel heater is connected) Preparations in the field Maximum cable length is 10 m (32ft)
  • Page 27 TROUBLESHOOTING 10. TROUBLESHOOTING 10-1. CAUTIONS ON TROUBLESHOOTING (1) Before troubleshooting, check the followings: Check the power supply voltage. Check the indoor/outdoor connecting wire for mis-wiring. (2) Take care the followings during servicing. Before servicing the air conditioner, be sure to turn off the remote controller first to stop the main unit, and then turn off the breaker.
  • Page 28 TROUBLESHOOTING 10-2. SELF-CHECK FUNCTION • Refer to the installation manual that comes with each remote controller for details. [Output pattern A] Errors detected by indoor unit Wired remote Wireless remote controller controller Beeper sounds/ Symptom Remark OPERATION Check code INDICATOR lamp blinks (Number of times) Intake sensor error P2, P9...
  • Page 29 TROUBLESHOOTING ● If the unit cannot be operated properly after test run, refer to the following table to fi nd the cause. Symptom Cause Wired remote controller LED 1, 2 (PCB in outdoor unit) Please Wait For about 3 After LED 1, 2 are lit, LED 2 is turned •...
  • Page 30 TROUBLESHOOTING 10-3. SELF-DIAGNOSIS ACTION TABLE Note: Errors to be detected in outdoor unit, such as codes starting with F, U or E (excluding E0 to E7), are not covered in this document. Please refer to the outdoor unit's service manual for the details. Check code Abnormal point and detection method Cause...
  • Page 31 TROUBLESHOOTING Check code Abnormal point and detection method Cause Countermeasure Drain pump lock protection operation Malfunction of drain pump Check if drain pump works. Suspected abnormality, if drain pump stops Clogged drain pump for 5 seconds continuously with drain pump Disconnected drain pump Check if connector (CNP) is connected.
  • Page 32 TROUBLESHOOTING Check code Abnormal point and detection method Cause Countermeasure Pipe temperature thermistor/Condenser/ Evaporator (TH5) The unit is in 3-minute resume protection Defective thermistor – Check resistance value of thermistor. mode if short/open of thermistor is characteristics For characteristics, refer to (P1). detected.
  • Page 33 TROUBLESHOOTING Check code Abnormal point and detection method Cause Countermeasure Remote controller transmission error(E3)/ signal receiving error(E5) 2 remote controllers are set as Set a remote controller to main, and the Abnormal if remote controller could not find “main.” other to sub. blank of transmission path for 6 seconds (In case of 2 remote controllers) and could not transmit.
  • Page 34 TROUBLESHOOTING Refrigerant leakage Refrigerant leaks from the • While the error is being displayed, the Abnormal if refrigerant leakage detected by a piping or the heat exchanger in indoor unit fan continues operating. refrigerant sensor. the indoor unit. • Ventilate the room well, make sure that The following items are used there is no ignition source, and then turn off around the indoor unit.
  • Page 35 TROUBLESHOOTING 10-4. TROUBLESHOOTING BY INFERIOR PHENOMENA Phenomena Cause Countermeasure (1) LED2 on indoor controller • When LED1 on indoor controller board is also off. board is off. Power supply of rated voltage is not supplied Check the voltage of outdoor power supply terminal to outdoor unit.
  • Page 36 TROUBLESHOOTING 10-5. TEST POINT DIAGRAM 10-5-1. Indoor controller board CN24A CN2L CN4F CN105 CN115 CN44 CN24 CN51 CN60 CN90 CNACL CN32 CN20 CN22 CNSA CN3C CNMF Emergency operation CN4F Float switch for mode selection CN115 IT terminal for capacity code CN105 IT terminal for system selection...
  • Page 37 TROUBLESHOOTING 10-6. TROUBLE CRITERION OF MAIN PARTS Part name Check method and criterion Room temperature Measure the resistance with a tester. thermistor (Part temperature 10°C (50˚F) ~ 30°C (86˚F)) (TH1) Normal Abnormal Pipe temperature 4.3 kΩ~9.6 kΩ Opened or short-circuited thermistor/liquid (TH2) Condenser/evaporator...
  • Page 38 TROUBLESHOOTING 10-7. Thermistor <Thermistor Characteristic graph> < Thermistor for lower temperature > Room temperature thermistor (TH1) Thermistor for Pipe temperature thermistor (TH2) lower temperature Condenser/evaporator temperature thermistor (TH5) Thermistor R =15kΩ ± 3% Fixed number of B=3480kΩ ± 2% – Rt=15exp { 3480( 273+t 0°C...
  • Page 39 TROUBLESHOOTING 10-9. FUNCTIONS OF DIP SWITCH AND JUMPER WIRE Each function is controlled by the dip switch and the jumper wire on control p.c. board. SW1 and SW2 are equipped only for service parts. Model setting and capacity setting are memorized in the nonvolatile memory of the control p.c. board of the unit. (Marks in the table below) Jumper wire ( ○: Short ×: Open) Jumper wire...
  • Page 40 DISASSEMBLY PROCEDURE 11. DISASSEMBLY PROCEDURE Exercise caution when removing heavy parts. 1. Control box 1. Removing the control box cover (1) Remove the two fixing screws on the cover (A) to remove it. • Tighten screws to a torque of 2.0±0.2 N·m. Fig.
  • Page 41 DISASSEMBLY PROCEDURE Exercise caution when removing heavy parts. 3. R454B sensor 1. Remove the control box cover according to the procedure in section 1, and remove the remove the R454B sensor connector from CNSA terminal explained in section 10-5-1. 2. Removing the filter and the bottom plate (1) Push up the tab on the filter in the direction of arrow (a), and pull out the filter in the direction of the arrow 1.
  • Page 42 DISASSEMBLY PROCEDURE Exercise caution when removing heavy parts. 4. Drain pan 1. Removing the filter and the bottom plate (1) Push up the tab on the filter in the direction of arrow (a), and pull out the filter in the direction of the arrow 1.
  • Page 43 DISASSEMBLY PROCEDURE Exercise caution when removing heavy parts. 5. Drain pump 1. Remove the control box cover according to the procedure in section 1, and remove the drain pump connector. 2. Remove the bottom plate and drain pan according to the procedure in section 4. 3.
  • Page 44 DISASSEMBLY PROCEDURE Exercise caution when removing heavy parts. 7. Fan and fan motor 1. Removing the filter and the bottom plate (1) Push up the tab on the filter in the direction of arrow (a), and pull out the filter in the direction of the arrow 1.
  • Page 45 DISASSEMBLY PROCEDURE Exercise caution when removing heavy parts. 8. Heat exchanger 1. Remove the drain pan according to the procedure in section 4. 2. Remove the heat exchanger cover according to the procedure in section 6-2. 3. Removing the cover (1) Remove the two fixing screws on the cover (M) to remove it.
  • Page 46 INSPECTION AND MAINTENANCE 12. INSPECTION AND MAINTENANCE 12-1. GUIDELINE FOR PREVENTIVE MAINTENANCE The following maintenance intervals indicate the estimated intervals of parts replacement and repair to be required as a result of periodic inspections. They do not necessarily mean that replacement is required at the maintenance intervals. The maintenance intervals do not indicate the warranty period.
  • Page 47 INSPECTION AND MAINTENANCE 12-2. RECOMMENDED PARTS INSPECTION INTERVAL Inspection Maintenance Parts Inspection items Criteria Measures interval interval • Visual check for dirt or • Filter element is seen • Clean the filter if it is Long-life torn. through. dirty. 5 years filter •...
  • Page 48 INSPECTION AND MAINTENANCE • The table above shows the main parts. Check the maintenance contract for details. • This maintenance interval is an estimated period until the day when the maintenance should be conducted to use the product safely for a long time. Make use of the table above for maintenance planning (such as planning budget for parts replacement cost).
  • Page 49 www.MitsubishiElectric.com New publication effective Oct. 2024 Specifications subject to change without notice HWE24090...

This manual is also suitable for:

Sez-ad09nlSez-ad12nlSez-ad15nlSez-ad18nl