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Mitsubishi Electric American Standard NAXWST B AA Series Service Manual
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Mitsubishi Electric American Standard NAXWST B AA Series Service Manual

Mitsubishi Electric American Standard NAXWST B AA Series Service Manual

Outdoor/indoor unit, hfc utilized r410a
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OUTDOOR UNIT
SERVICE MANUAL
Models
NAXSST30B112AA
NAXSST36B112AA
NAYSST30B112AA
NAYSST36B112AA
HFC
utilized
R410A
Indoor unit service manual
NAXWST/NAYWST•B•AA Series (OBHA874)
CONTENTS
1. TECHNICAL CHANGES ······························2
2. PART NAMES AND FUNCTIONS ··················3
3. SPECIFICATION ········································4
4. OUTLINES AND DIMENSIONS ·····················6
5. WIRING DIAGRAM ·····································7
6. REFRIGERANT SYSTEM DIAGRAM ·············8
7. DATA······················································ 10
8. ACTUATOR CONTROL ····························· 17
9. SERVICE FUNCTIONS ······························ 18
10. TROUBLESHOOTING ······························· 19
11. DISASSEMBLY INSTRUCTIONS ················· 39
PARTS CATALOG (OBBA875)
No. OBHA875

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Summary of Contents for Mitsubishi Electric American Standard NAXWST B AA Series

  • Page 1 OUTDOOR UNIT No. OBHA875 utilized SERVICE MANUAL R410A Models NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA Indoor unit service manual NAXWST/NAYWST•B•AA Series (OBHA874) CONTENTS 1. TECHNICAL CHANGES ······························2 2. PART NAMES AND FUNCTIONS ··················3 3. SPECIFICATION ········································4 4. OUTLINES AND DIMENSIONS ·····················6 5. WIRING DIAGRAM ·····································7 6.
  • 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 PART NAMES AND FUNCTIONS NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA Air inlet (back and side) Piping Air outlet Drain hose Drain outlet OBHA875...
  • Page 4 SPECIFICATION NAXSST30B112AA NAXSST36B112AA Outdoor unit model NAYSST30B112AA NAYSST36B112AA 30,700 32,000/33,200 Btu/h Cooling *1 (10,300 ~ 30,700) (10,300 ~ 32,000)/(10,300 ~ 33,200) Capacity Rated (Minimum~Maximum) 32,600 35,200 Btu/h Heating 47 *1,3 (9,800 ~ 34,000) (9,800 ~ 36,000) Capacity Btu/h 20,000 (20,800) 21,600 (22,800) Heating 17 *2,3 Rated (Maximum)
  • Page 5 Test condition *4, *5 Indoor air condition (°F) Outdoor air condition (°F) Mode Test AHRI Dry bulb Wet bulb Dry bulb Wet bulb 210/240 "A-Full" Cooling Steady State (75) at rated compressor speed "B-Full" Cooling Steady State (65) at rated compressor speed SEER "B-Low"...
  • Page 6 OUTLINES AND DIMENSIONS NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA Unit: inch REQUIRED SPACE 4 in OR MORE. 14 in OR MORE. 16-7/16 AIR IN ↓ DRAIN HOLE ø1-21/32 → 20 in OR MORE. AIR IN OPEN TWO SIDES OF RIGHT 4 in OR MORE. OR REAR SIDE.
  • Page 7 WIRING DIAGRAM NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA OBHA875...
  • Page 8 REFRIGERANT SYSTEM DIAGRAM NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA Unit: inch (mm) Service port (high pressure) Refrigerant pipe ø 5/8 Muffler 4-way valve (with heat insulator) Strainer #100 Stop valve Outdoor Flared connection Discharge heat Ambient temperature exchanger temperature thermistor thermistor RT62 RT65 Service port Compressor...
  • Page 9 MAX. REFRIGERANT PIPING LENGTH and MAX. HEIGHT DIFFERENCE Refrigerant piping: ft. Piping size O.D: in. Model Max. Length Max. Height difference Liquid NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA Indoor unit Max. Height difference Max. Length Outdoor unit ADDITIONAL REFRIGERANT CHARGE (R410A: oz.) NOTE: Refrigerant piping exceeding 25 ft.
  • Page 10 DATA NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA 7-1. PERFORMANCE DATA 1) COOLING CAPACITY Indoor air Outdoor intake air DB temperature (˚F) Model IWB (˚F) 37.6 22.1 0.59 2.95 35.2 20.6 0.59 3.24 33.0 19.4 0.59 3.49 NAXSST30B112AA 35.6 25.6 0.72 2.79 33.2 23.9 0.72 3.07...
  • Page 11 4) HEATING CAPACITY Indoor air Outdoor intake air WB temperature (˚F) Model IDB (˚F) 14.3 1.97 18.9 2.49 23.6 2.92 28.2 3.26 31.8 3.42 32.8 3.47 37.2 3.61 NAXSST- 15.5 1.89 20.0 2.40 24.5 2.86 28.9 3.17 32.6 3.34 33.6 3.41 38.0 3.54...
  • Page 12 Heating Heating capacity (at Rated frequency) Outdoor intake air WB temperature (°F) NAXSST30B112AA NAXSST36B112AA Airflow = 803 CFM Airflow = 803 CFM Outdoor intake air WB temperature (°F) Outdoor intake air WB temperature (°F) This value of frequency is not the same as the actual frequency in operating. Refer to 7-5 and 7-6 for the relationships between frequency and capacity.
  • Page 13 7-3. CONDENSING PRESSURE Cooling Data are based on the condition of indoor humidity 50 %. Air flow should be set to High speed. NAXSST30B112AA NAYSST30B112AA (PSIG) (PSIG) (°F) 95 100 105 110 115 (°F) 95 100 105 110 115 Outdoor ambient temperature Outdoor ambient temperature NAXSST36B112AA NAYSST36B112AA (PSIG)
  • Page 14 Heating Data are based on the condition of outdoor humidity 75%. Air flow should be set to High speed. Data are for heating operation without any frost. NAXSST30B112AA (PSIG) (PSIG) (°F) (°F) Outdoor ambient temperature Outdoor ambient temperature NAXSST36B112AA (PSIG) (PSIG) (°F) (°F)
  • Page 15 7-4. STANDARD OPERATION DATA NAXWST30B112AA NAXWST36B112AA Model NAYWST30B112AA NAYWST36B112AA Item Unit Cooling Heating Cooling Heating Capacity Btu/h 30,700 32,600 32,000/33,200 35,200 — 0.72 — 0.69 — Input 3.32 3.34 3.63/3.77 3.74 Rated frequency NAXWST30B112AA NAXWST36B112AA Indoor unit NAYWST30B112AA NAYWST36B112AA Power supply phase, 208/230, 1, 60 Cooling: 0.078...
  • Page 16 7-5. CAPACITY AND INPUT CORRECTION BY INVERTER OUTPUT FREQUENCY NAXSST30B112AA NAYSST30B112AA Correction of Cooling capacity Correction of Cooling total input Correction of Heating total input Correction of Heating capacity (Hz) (Hz) (Hz) (Hz) The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor The operational frequency of compressor NAXSST36B112AA NAYSST36B112AA (208V)
  • Page 17 ACTUATOR CONTROL NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA 8-1. OUTDOOR FAN MOTOR CONTROL The fan motor turns ON/OFF, interlocking with the compressor. [ON] The fan motor turns ON 5 seconds before the compressor starts up. [OFF] The fan motor turns OFF 15 seconds after the compressor has stopped running. 5 seconds 15 seconds Compressor...
  • Page 18 SERVICE FUNCTIONS NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA 9-1. CHANGE IN DEFROST SETTING Changing defrost finish temperature <JS> To change the defrost finish temperature, cut/solder the JS wire of the outdoor inverter P.C. board (Refer to 10-6.1.). Defrost finish temperature Jumper NAXSST30/36B112AA NAYSST30/36B112AA Soldered 50°F (10°C)
  • Page 19 TROUBLESHOOTING NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA 10-1. 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 main unit first with the remote controller, then after con- firming the horizontal vane is closed, turn off the breaker and/or disconnect the power plug.
  • Page 20 10-2. FAILURE MODE RECALL FUNCTION Outline of the function This air conditioner can memorize the abnormal condition which has occurred once. Even though LED indication listed on the troubleshooting check table (10-3.) disappears, the memorized failure details can be recalled. 1.
  • Page 21 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. Make sure that the remote controller is set to the failure mode recall function. 1.
  • Page 22 NOTE: Blinking patterns of this mode differ from the ones 3. Outdoor unit failure mode table of TROUBLESHOOTING CHECK TABLE (10-3.). The left lamp of the Indoor/outdoor Outdoor unit OPERATION Abnormal point LED indication unit failure Condition Remedy failure mode INDICATOR (Failure mode/protection) (Outdoor P.C.
  • Page 23 NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.). The left lamp of the Indoor/outdoor Outdoor unit OPERATION Abnormal point LED indication unit failure Condition Remedy failure mode INDICATOR (Failure mode/protection) (Outdoor P.C. board) mode recall recall function lamp...
  • Page 24 10-3. TROUBLESHOOTING CHECK TABLE Abnormal point/ Symptom LED indication Condition Remedy Condition Outdoor unit 1-time blink every Outdoor power sys- Overcurrent protection cut-out operates 3 consecutive times • Reconnect connector of compres- does not op- 2.5 seconds within 1 minute after the compressor gets started. sor.
  • Page 25 Abnormal point/ Symptom LED indication Condition Remedy Condition Outdoor unit 1-time blink Frequency drop by Current from power outlet is nearing breaker capacity. The unit is normal, but check the operates. 2.5 seconds OFF current protection following. • Check if indoor filters are clogged. •...
  • Page 26 10-4. TROUBLESHOOTING CRITERION OF MAIN PARTS NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA Part name Check method and criterion Figure Defrost thermistor (RT61) Measure the resistance with a tester. Refer to 10-6. “Test point diagram and voltage”, 1. “Inverter P.C. Fin temperature board”, for the chart of thermistor. thermistor (RT64) Ambient temperature thermistor (RT65)
  • Page 27 10-5. TROUBLESHOOTING FLOW A How to check inverter/compressor Disconnect the connector between the compressor and the power module (IC700). Check the voltage between terminals. See 10-5. “Check of open phase”. Replace the inverter P.C. board. Are the voltages balanced? Check the compressor. See 10-5.
  • Page 28 D Check of compressor winding ●Disconnect the connector between the compressor and the power module (IC700), and measure the resistance between the compressor terminals. <<Measurement point>> At 3 points BLK-WHT *Measure the resistance between the lead wires at 3 points. BLK-RED WHT-RED <<Judgement>>...
  • Page 29 G Check of outdoor thermistors Disconnect the connector of thermistor in the inverter P.C. board (see below table), and measure the resistance of thermistor. Replace the thermistor except RT64. Is the resistance of thermistor normal? When RT64 is abnormal, replace the inverter P.C. (Refer to 10-6.1.) board.
  • Page 30 H Check of R.V. coil NAXSST30/36 * First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 10-4. * In case CN602 is disconnected or R.V. coil is open, voltage is generated between the terminal pins of the connector although no signal is being transmitted to R.V.
  • Page 31 I Check of outdoor fan motor Disconnect the connectors CN931 and CN932 from the inverter P.C. board. Check the connection between the connector CN931 and CN932. Is the resistance between each ter- minal of outdoor fan motor normal? (Refer to 10-4.) Disconnect CN932 from the inverter P.C.
  • Page 32 J Check of power supply Disconnect the connector between the compressor and the power module (IC700). Rectify indoor/outdoor Turn ON power supply and press the emergency operation switch. connecting wire. Does the left lamp of the Is there voltage 208/230 VAC Replace the indoor OPERATION INDICATOR lamp on between the indoor terminal...
  • Page 33 K Check of LEV (Expansion valve) Turn ON the power supply. <Preparation of the remote controller> While pressing both Operation select button and NAX type TEMP button on the remote controller at the same time, press RESET button. First, release RESET button. Hold down the other 2 buttons for another 3 seconds.
  • Page 34 L Check of inverter P.C. board Check the outdoor fan motor. (Refer to 10-5. .) Is the fuse (F901) blown on the in- verter P.C. board? Check the connection of the connectors (CN931, CN932) of the outdoor fan motor. If the connection is poor, make it correct. Operate the outdoor unit by starting EMERGENCY OPERATION.
  • Page 35 M How to check miswiring and serial signal error Turn OFF the power supply. Is there rated voltage AC in Check the power supply. the power supply? Turn ON the power supply. Is there rated voltage between outdoor terminal block S1 and Check the wiring.
  • Page 36 N Check of outdoor refrigerant circuit The operation has stopped to prevent the diesel explosion caused by air trapped in the refrigerant circuit. Close the stop Has the operation stopped during pump down? valve, and disconnect the power plug or turn the breaker OFF. CAUTION : Do not start the operation again to prevent hazards.
  • Page 37 O Electromagnetic noise enters into TV sets or radios Is the unit grounded? Ground the unit. Is the distance between the antennas Extend the distance between the antennas and and the indoor unit within 9.91 ft. (3m), the indoor unit, and/or the antennas and the or is the distance between the antennas outdoor unit.
  • Page 38 10-6. TEST POINT DIAGRAM AND VOLTAGE 1. Inverter P.C. board NAXSST30B112AA NAXSST36B112AA NAYSST30B112AA NAYSST36B112AA Back side of unit Smoothing Smoothing Smoothing Fuse (F880) Output to drive Capacitor Capacitor Capacitor T3.15AL250V outdoor fan motor (CB3) (CB1) (CB2) (CN932) 208/230 V AC R.V.
  • Page 39 DISASSEMBLY INSTRUCTIONS <"Terminal with locking mechanism" Detaching points> The terminal which has the locking mechanism can be detached as shown below. There are 2 types (refer to (1) and (2)) 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 40 OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the inverter assembly and inverter P.C. Screws of the conduit cover Photo 3 board (1) Remove the cabinet and panels. (Refer to section 1.) (2) Disconnect the lead wire to the reactor and the following connectors: <Inverter P.C.
  • Page 41 OPERATING PROCEDURE PHOTOS/FIGURES Photo 7 Connection procedure when attaching the inverter P.C. board (Photo 8, 9) 1. Attach the heat sink support to the P.C. board support. 2. Hook the lead wires of the compressor, the reactor and the P.C. board to each hooks on the heat sink support as shown Photo 8.
  • Page 42 OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing the discharge temperature thermistor, Photo 10 Outdoor heat exchanger defrost thermistor, outdoor heat exchanger tempera- temperature thermistor ture thermistor and ambient temperature thermistor (1) Remove the cabinet and panels. (Refer to section 1.) (2) Disconnect the lead wire to the reactor and the following connectors: <Inverter P.C.
  • Page 43 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing the compressor and 4-way valve Photo 12 (1) Remove the top panel, cabinet and service panel. (Refer to Brazed part of Brazed part of section 1.) the discharge pipe the suction pipe (2) Remove the back panel. (Refer to section 1.) (3) Remove the inverter assembly.
  • Page 44 MITSUBISHI ELECTRIC TRANE HVAC US LLC HEAD OFFICE: 1340 SATELLITE BOULEVARD, SUWANEE, GA 30024, USA © Copyright 2021 MITSUBISHI ELECTRIC CORPORATION Published: Feb. 2021. No. OBHA875 Specifications are subject to change without notice. Made in Japan...

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American standard naywst b aa seriesAmerican standard naxsst30b112aaAmerican standard naxsst36b112aaAmerican standard naysst30b112aaAmerican standard naysst36b112aa