Mitsubishi Heavy Industries SRK20ZSX-W Service Manual
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Mitsubishi Heavy Industries SRK20ZSX-W Service Manual

Inverter multi-split system residential air conditioner
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SERVICE MANUAL
INVERTER MULTI-SPLIT SYSTEM
RESIDENTIAL AIR-CONDITIONERS
(Split system, air to air heat pump type)
(OUTDOOR UNIT)
SCM71ZS-W
80ZS-W
(INDOOR UNIT)
Wall mounted type
SRK20ZSX-W,-WB,-WT
25ZSX-W,-WB,-WT
35ZSX-W,-WB,-WT
50ZSX-W,-WB,-WT
60ZSX-W,-WB,-WT
SRK20ZS-W,-WB,-WT
25ZS-W,-WB,-WT
35ZS-W,-WB,-WT
50ZS-W,-WB,-WT
SRK71ZR-W
Duct connected-Low/Middle static pressure type
FDUM50VH
SRR25ZM-W
35ZM-W
50ZS-W
60ZS-W
FDE50VH
Manual No.'19・SCM-SM-276
4-way ceiling cassette type
FDTC25VH
35VH
50VH
60VH

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  • Page 1 INVERTER MULTI-SPLIT SYSTEM RESIDENTIAL AIR-CONDITIONERS (Split system, air to air heat pump type) (OUTDOOR UNIT) SCM71ZS-W 80ZS-W (INDOOR UNIT) Wall mounted type Ceiling concealed type 4-way ceiling cassette type SRK20ZSX-W,-WB,-WT SRR25ZM-W FDTC25VH 25ZSX-W,-WB,-WT 35ZM-W 35VH 35ZSX-W,-WB,-WT 50ZS-W 50VH 50ZSX-W,-WB,-WT 60ZS-W...
  • Page 3 '19 • SCM-SM-276 CONTENTS 1. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER ....7 1.1 SRK and SRR series ...................7 1.1.1 SRK-ZSX series ..................7 (1) Operation control function by wireless remote control .......7 (2) Unit ON/OFF button ...................8 (3) Auto restart function ..................8 (4) Installing two air-conditioners in the same room ..........8...
  • Page 4 '19 • SCM-SM-276 (11) Timer operation ..................22 (12) Silent operation ..................22 (13) Night setback operation ................22 (14) Air flow range setting ................23 (15) Display brightness adjustment ..............23 (16) Outline of dehumidifying (DRY) operation ..........24 (17) Outline of automatic operation ..............24 (18) Protective control function ................25 1.1.3 SRK-ZR series ..................26...
  • Page 5 '19 • SCM-SM-276 (9) Night setback operation ................39 (10) Determining the operating mode .............39 (11) Drain pump abnormalities detection ............39 (12) Outline of dehumidifying (DRY) operation ..........40 (13) Outline of automatic operation ...............40 (14) Operation permission/prohibition control ..........41 (15) External control (remote display)/control of input signal .......41 (16) Hot keep operation ................42...
  • Page 6 '19 • SCM-SM-276 (21) Operation permission/prohibition ...............60 (22) Temporary stop input ................62 (23) Selection of cooling/heating external input function ........62 (24 ) Fan control at heating startup ..............63 (25) Room temperature detection temperature compensation during heating ....63 (26) Return air temperature compensation ............63 (27) High power operation (RC-EX3A only) .............63...
  • Page 7 '19 • SCM-SM-276 (9) Compressor overheat protection ..............74 (10) Current safe ....................74 (11) Current cut ....................75 ..................75 (12) Outdoor unit failure (13) Discharge pipe sensor disconnection protection control ......75 (14) Regulation of outdoor air flow ..............76 (15) Serial signal transmission error protection ..
  • Page 8 '19 • SCM-SM-276 (7) Outdoor unit inspection points ..............110 2.2.2 Troubleshooting flow .................111 (1) List of troubles ..................111 (2) Troubleshooting ..................112 3. ELECTRICAL WIRING ..................156 4. PIPING SYSTEM ..................164...
  • Page 9 '19 • SCM-SM-276 1. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER 1.1 SRK and SRR series 1.1.1 SRK-ZSX series (1) Operation control function by wireless remote control Transmission section Operation section ON/OFF (luminous) button OPERATION MODE select button Press to start operation, press again Each time the button is pressed, the to stop.
  • Page 10 '09•SRK-DB-087D '19 • SCM-SM-276 '09•SRK-DB-087D (2) Unit ON/OFF button (2) Unit ON/OFF button wireless wireless (a) Operation (a) Operation (b) Details of operation room (b) Details of operation whether to go into the COOL or HEAT modes. Function Room temperature Fan speed Flap/Louver Timer switch setting Operation mode...
  • Page 11 '19 • SCM-SM-276 Jumpre wire (J1) (5) Selection of the annual cooling function (a) The annual cooling control is valid from factory default setting. It is possible to disable by cutting jumper wire (J3), or changing the setting of DIP switch (SW2-4) on the interface kit (option) PCB if it is connected.
  • Page 12 '19 • SCM-SM-276 (8) Economy operation Pressing the HI POWER/ECONOMY button initiate a soft operation with the power suppressed in order to avoid an excessive cooling (a) Pressing the HI/ECO button initiates a soft operation with the power suppressed in order to avoid an excessive cooling or heating. (b) The remote control displays.
  • Page 13 Wireless remote   Angle of flap from horizontal control display '19 • SCM-SM-276 Wireless remote COOL, DRY, FAN Approx. 15° Approx. 20° Approx. 25° Approx. 30° Approx. 55° control display HEAT Approx. 30° Approx. 40° Approx. 45° Approx. 50° Approx. 55° Approx.
  • Page 14 Cooling AUTO AUTO HIGH POWER AUTO < = < = Room temp. – Setting temp. >5°C Room temp. – Setting temp. 5°C Room temp. – Setting temp. >5°C Room temp. – Setting temp. 5°C < = Cooling Cooling Setting temp. – Room temp. >5°C Setting temp.
  • Page 15 '09•SRK-DB-087D '09•SRK-DB-087D '19 • SCM-SM-276 (11) Timer operation (12) Silent operation (a) Comfort start-up (ON timer operation) (11) Timer operation When the silent operation is set, the unit operates by dropping the outdoor fan speed and the compressor speed. The unit starts the operation 5 to 60 minutes earlier so that the room can approach optimum temperature at ON timer. (a) Comfort start-up (ON timer operation) SCM71 SCM80...
  • Page 16 '19 • SCM-SM-276 (15) Display brightness adjustment This function can be used when it is necessary to adjust the brightness of unit display. Brightness level Timer light Run light 100% 100% Note (1) When the unit displays self diagnosis or service mode, brightness level is always LV2. (16) AUTO OFF operation In order to prevent the air-conditioner from continuing to operate although the person(s) has already left the room, the air-conditioner automatically stops approximalely 1 hour (or 2 hours) after the sensor judges that there is no one in the room.
  • Page 17 12-74rps 12-86rps 12-110rps 12-50rps 12-58rps 12-34rps 12-38rps 12-54rps 12-70rps 12-90rps 12-30rps 12-34rps 12-42rps 12-50rps 12-66rps '19 • SCM-SM-276 12-30rps 12-30rps 12-30rps 12-30rps 12-30rps 12-34rps 12-38rps 12-54rps 12-70rps 12-90rps (18) Outline of automatic operation (a) Determination of operation mode (a) Determination of operation mode Operation mode is determined by indoor air temperature and outdoor air temperature as following.
  • Page 18 '09•SRK-DB-087D '09•SRK-DB-087D has elapsed '19 • SCM-SM-276 Current safe (b) Frost prevention control Purpose (b) Frost prevention control Operating conditions Operating conditions (Command speed) (ii) Detail of operation (Command speed) Compressor speed Compressor speed (ii) Detail of anti-frost operation Reduce (ii) Detail of anti-frost operation Indoor heat exchanger Reduce...
  • Page 19 '19 • SCM-SM-276 1.1.2 SRK-ZS series (1) Operation control function by wireless remote control Transmission section Operation section ON/OFF (luminous) button Press to start operation, press again to stop. OPERATION MODE select button Each time the button is pressed, the FAN SPEED button mode changes.
  • Page 20 '09•SRK-DB-087D '19 • SCM-SM-276 '09•SRK-DB-087D (2) Unit ON/OFF button (2) Unit ON/OFF button wireless wireless (a) Operation (a) Operation (b) Details of operation room (b) Details of operation whether to go into the COOL or HEAT modes. Function Room temperature Fan speed Flap/Louver Timer switch setting Operation mode...
  • Page 21 '19 • SCM-SM-276 J1 用 J3 用 (5) Selection of the annual cooling function Jumper wire (J1) Jumper wire (J3) (a) The annual cooling control is valid from factory default setting. It is pos- sible to disable by cutting jumper wire (J3), or changing the setting of DIP switch (SW2-4) on the interface kit (option) PCB if it is connected.
  • Page 22 '19 • SCM-SM-276 (8) Economy operation Pressing the HI POWER/ECONOMY button initiate a soft operation with the power suppressed in order to avoid an excessive cooling or heating. The unit operate 1.5℃ higher than the setting temperature during cooling or 2.5℃ lower than that during heating.
  • Page 23 control display Left approx. 50° Left approx. 20° Center Right approx. 20° Right approx. 50° Center installation Right end installation Left approx. 50° Left approx. 45° Left approx. 30° Center Right approx. 20° '19 • SCM-SM-276 Left approx. 20° Center Right approx.
  • Page 24 Cooling Heating '19 • SCM-SM-276 Flap Up/down swing Louver Center (Fixed) Cooling Heating Flap Horizontal blowing (Fixed) Slant forwardl blowing (Fixed) Louver Wide (Fixed) room Operation mode Air flow direction contorol < = < = Room temp. – Setting temp. 2°C 2°C <...
  • Page 25 The OFF timer can be set at a specific time (in 10-minute units) within a 24-hour period. (c) OFF timer operation The OFF timer can be set at a specific time (in 10-minute units) within a 24-hour period. (d) Weekly timer operation '19 •...
  • Page 26 '19 • SCM-SM-276 '09•SRK-DB-087D (16)　Outline of dehumidifying (DRY) operation (d) Countermeasure for excessive temperature rise If it feels excessive temperature rise in heating operation, setting temperature can be lower. (a) Purpose of DRY mode The purpose is "Dehumidification", and not to control the humidity to the target condition. Indoor/outdoor unit control the operation condition to reduce the humidity, and also prevent over cooling.
  • Page 27 Compressor overheat protection Purpose: '19 • SCM-SM-276 (ii) Detail of operation (18) Protective control function (Example) Fuzzy Dew prevention control [Cooling] Prevents dewing on the indoor unit. (i) Operating conditions When the following conditions have been satisfied for more than 30 minutes after starting operation Detected value of humidity is 68% or higher.
  • Page 28 '19 • SCM-SM-276 1.1.3 SRK-ZR series (1) Operation control function by wireless remote control Operation section Transmission section OPERATION MODE select button ON/OFF (luminous) button Each time the button is pressed, the mode changes. Press to start operation, press again to stop.
  • Page 29 '19 • SCM-SM-276 '09•SRK-DB-087D (2) Unit ON/OFF button wireless wireless (a) Operation (b) Details of operation COOL, DRY HEAT Function Indoor temperature Fan speed Flap/Louver Timer Switch setting Operation mode COOL Unit ON/OFF button HEAT (3) Auto restart function Jumper wire (JA1) (ii) (JA1) (4) Installing two air-conditioners in the same room...
  • Page 30 '19 • SCM-SM-276 (5) Selection of the annual cooling function The annual cooling control is valid from factory default setting. It is possible to dis- Jumper wire (JA3) able by cutting jumper wire (JA3), or changing the setting of DIP switch (SW2-4) on the interface kit (option) PCB if it is connected.
  • Page 31 ③ When the operation is retrieved from CLEAN or ALLERGEN CLEAR operation. (b) When the following operation are set, ECONOMY operation will be canceled. ① When the HI POWER/ECONO button is pressed again. '19 • SCM-SM-276 ② When the operation mode is changed DRY to FAN. (c) Not operable while the air-conditioner is OFF.
  • Page 32 display Center installation Left Approx. 50° Left Approx. 20° Center Right Approx. 20° Right Approx. 50° '19 • SCM-SM-276 (c) Swing (ii) In HEAT operation In COOL, DRY, FAN operation Approx. 5° Approx. 35° Approx. 60° Approx. 70° (d) Memory ap (Flap or Louver stopped) '09•SRK-DB-087D (e) When not operating (9) 3D auto operation...
  • Page 33 Cooling Heating '19 • SCM-SM-276 Flap Up/down swing Center (Fixed) Louver Cooling Heating Flap Horizontal blowing (Fixed) Slant forwardl blowing (Fixed) Wide (Fixed) Louver Operation mode Air flow direction contorol Indoor temp. – Setting temp. 2°C < = 2°C < Indoor temp. – Setting temp. 5°C <...
  • Page 34 (c) OFF timer operation '19 • SCM-SM-276 (13) Air flow range setting wireless (a) Setting If the air-conditioning unit is running, press the ON/OFF button to stop. (ii) Press the AIR FLOW U/D (UP/DOWN) button and the AIR FLOW L/R (LEFT/RIGHT) button together for 5 seconds or more.
  • Page 35 (15) Outline of cooling operation '19 • SCM-SM-276 (a) Operation of major functional components in cooling mode '09•SRK-DB-087D Cooling Thermostat ON Thermostat OFF Failure (14) Outline of dehumidifying (DRY) operation Compressor Indoor fan motor (a) Purpose of DRY mode (15) Outline of cooling operation The purpose is "Dehumidification", and not to control the humidity to the target condition.
  • Page 36 '19 • SCM-SM-276 (16) Protective control function (a) Dew prevention control [Cooling]: Prevents dewing on the indoor unit. Operating conditions When the following conditions have been satisfied for more than 30 minutes after starting operation. The compressor is ON. Detected value of humidity is 68% or higher. (ii) Contents of operation Air capacity control...
  • Page 37 '19 • SCM-SM-276 1.1.4 SRR series (1) Operation control function by wireless remote control Operation section Transmission section OPERATION MODE select button ON/OFF (luminous) button Each time the button is pressed, the mode changes. Press to start operation, press again to stop.
  • Page 38 '19 • SCM-SM-276 (2) Unit ON/OFF button When the wireless remote control batteries become weak, or if the wireless remote control is lost or malfunctioning, this button may be used to turn the unit on and off. Operation Push the button once to place the unit in the automatic mode. Push it once more to turn the unit off. Details of operation The unit will go into the automatic mode in which it automatically determines, from indoor temperature (as detected by sensor), whether to go into COOL, DRY or HEAT modes.
  • Page 39 '19 • SCM-SM-276 (4) Installing two air-conditioners in the same room (4) Installing two air-conditioners in the same room When two air-conditioners are installed in the room, use setting when the two air-conditioners are not operated with one When two air-conditioners are installed in the room, use setting when the two air-conditioners are not operated with one wireless remote control.
  • Page 40 '19 • SCM-SM-276 (b) Content of control (i) If the outdoor air temperature sensor (TH2 (Tho-A)) detects below 5°C, the indoor unit speed is switched to 9th step. (It is not possible to change.) (ii) If the outdoor air temperature sensor (TH2 (Tho-A)) detects higher than A°C, the indoor unit speed is changed to the normal control speed.
  • Page 41 '19 • SCM-SM-276 (8) 　 Timer operation Comfortable timer setting (ON timer) If the timer is set at ON when the operation select switch is set at the cooling or heating, or the cooling or heating in auto mode operation is selected, the comfortable timer starts and determines the starting time of next operation based on the initial value of 15 minutes and the relationship between the room temperature at the setting time and the set- ting temperature.
  • Page 42 '19 • SCM-SM-276 (ii) Control B If the float switch detects any anomalous drain condition, the drain pump motor is turned ON for 5 minutes, and at 10 seconds after the drain pump motor OFF it checks the float switch. If it is normal, the unit is stopped under the normal mode or, if there is any anomalous condition, displayed by the flashing of display lights and the drain pump motor is turned ON.
  • Page 43 (ii) '19 • SCM-SM-276 (iii) Signals of wireless remote control (Display) ±0 –6 –5 –4 –3 –2 –1 Cooling Setting Dehumidifying temperature Heating (e) When the unit is operated automatically with the wired remote control connected, the cooling operation is controlled according to the display temperatures while the setting temperature is compensated by +1°C during dehumidifying or by +2°C during heating.
  • Page 44 '19 • SCM-SM-276 (b) Control of input signal Control of input signal (switch input, timer input) connectors (CnT) are provided on the printed circuit board of indoor unit. However, when the operation of air-conditioner is under the “ CENTER ” mode, the wired remote control by CnT is invalid. Level input If the factory settings (Jumper wire J1 EXTERNAL INPUT on the PCB of indoor unit) are set, or “LEVEL IN- PUT”...
  • Page 45 '16 • PAC-T-251 '19 • SCM-SM-276 1.10 OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER 1.2 FDTC, FDUM and FDE series 1.2.1 Wired remote control (Option parts) 1.10.1 Remote control Model RC-EX3A Wired remote control Model RC-EX3A ⑤ LCD (with backlight) ③ F2 switch ④...
  • Page 46 '19 • SCM-SM-276 Wired remote control Model RC-E5 Model RC-E5 The figure below shows the remote control with the cover opened. Note that all the items that may be displayed in the liquid crystal display area are shown in the figure for the sake of explanation. Characters displayed with dots in the liquid crystal display area are abbreviated.
  • Page 47 '16 • PAC-T-251 '19 • SCM-SM-276 1.10.2 Operation control function by the wired remote control 1.2.2 Operation control function by the wired remote control ●Model RC-EX3A (1) Switching sequence of the operation mode switches of remote control (a) Tap the change operation mode button on the TOP screen. (b) When the change operation mode screen is displayed, tap the button of desired mode.
  • Page 48 '19 • SCM-SM-276 ●Content memorized with the power failure compensation are as follows. Note(1) Items (f) and (g) are memorized regardless whether the power failure compensation is effective or not while the setting of silent mode is cancelled regardless whether the power failure compensation is effective or not. At power failure –...
  • Page 49 '19 • SCM-SM-276 ● Model RC-E5 (1) Switching sequence of the operation mode switches of remote control COOL HEAT AUTO (2) CPU reset This functions when “CHECK” and “ESP” buttons on the remote control are pressed simultaneously. Operation is same as that of the power source reset.
  • Page 50 '19 • SCM-SM-276 1.2.3 Operation control function by the indoor control (1) Auto operation (a) If “Auto” mode is selected by the remote control, the heating and the cooling are automatically switched according to the difference between outdoor air temperature and setting temperature and the difference between setting temperature and return air temperature. (When the switching of cooling mode ↔ heating mode takes place within 3 minutes, the compressor does not operate for 3 minutes by the control of 3-minute timer.) This will facilitate the cooling/heating switching operation in intermediate seasons and the adaptation to unmanned operation at stores, etc (ATM corner of bank).
  • Page 51 '19 • SCM-SM-276 (ii) Regardless of the setting temperature, the cooling or heating operation mode is judged according to the "Judgment based on (ii) Regardless of the setting temperature, the cooling or heating operation mode is judged according to the “Judgment Room temperature/Cooling or Heating and Outdoor temperature/Cooling or Heating".
  • Page 52 '19 • SCM-SM-276 (4) Timer operation (a) RC-EX3A (i) Sleep timer Set the time from the start to stop of operation. The time can be selected in the range from 30 to 240 minutes (in the unit of 10-minute). Note (1) Enable the “Sleep timer” setting from the remote control. If the setting is enabled, the timer operates at every time. (ii) Set OFF timer by hour Set the time to stop the unit after operation, in the range from 1 to 12 hours (in the unit of hour). (iii) Set ON timer by hour Set the time to start the unit after the stop of operation, in the range from 1 to 12 hours (in the unit of hour). It is allowed also to set simultaneously the indoor temperature, operation mode, air flow rate and warm-up enabled/ disabled.
  • Page 53 '19 • SCM-SM-276 (5) Hot start (Cold draft prevention at heating) (a) Operating conditions When either one of following conditions is satisfied, the hot start control is performed. (i) From stop to heating operation (ii) From cooling to heating operation (iii) Form heating thermostat OFF to ON (iv) After completing the defrost operation (only on units with thermostat ON) (b) Contents of operation (i) Indoor fan motor control at hot start 1) Within 7 minutes after starting heating operation, the fan mode is determined depending on the condition of thermostat (fan control with heating thermostat OFF).
  • Page 54 '19 • SCM-SM-276 (7) Auto swing control (FDTC and FDE only) Note Even if [Auto Swing] is selected, the louver position with anti draft function is fixed to position 1. (a) RC-EX3A (i) Louver control 1) To operate the swing louver when the air-conditioner is operating, press the “Direction” button on the TOP screen of remote control. The wind direction select screen will be displayed. 2) To swing the louver, touch the “Auto swing” button. The lover will move up and down. To fix the swing louver at a position, touch one of [1] - [4] buttons. The swing lover will stop at the selected position.
  • Page 55 '19 • SCM-SM-276 (8) Thermostat operation (a) Cooling (i) Thermostat is operated with the room temperature control. (ii) Thermostat is turned ON or OFF relative to the set room temperature as shown below. Thermostat ON Temperature drop Thermostat OFF Temperature rise Set room temperature (iii) Thermostat is turned ON when the room temperature is in the range of -1 < Set temperature < +1 at the start of cooling operation (including from heating to cooling). (b) Heating (i) Thermostat is operated with the room temperature control. (ii) Thermostat is turned ON or OFF relative to the set room temperature as shown below.
  • Page 56 '19 • SCM-SM-276 (d) Fan control during cooling thermostat OFF (i) Following fan controls during the cooling thermostat OFF can be selected with the indoor function setting of the wired remote control. ① Low fanspeed, ② Set fan speed (Factory default), ③ Intermittence, ④ Fan OFF (ii) When the “Low fan speed” is selected, the following taps are used for the indoor fans. ・ ForDCmotor:ULotap (iii) When the “Set fan speed” is selected, it is operated with the set fan speed also in the thermostat OFF condition. (iv) If the “Intermittence” is selected, following controls are performed: 1) If the thermostat is turned OFF during the cooling operation, the indoor fan motor stops. 2) Indoor fan OFF is fixed for 5 minutes. After the 5 minutes, the indoor fan is operated at ULo for 2 minutes. In the meantime the louver is controlled at level. 3) After operating at ULo for 2 minutes, the indoor fan moves to the state of 1) above. 4) If the thermostat is turned ON, the fan starts operation at set fan speed. 5) When the cooling thermostat is turned OFF, the remote control displays the temperature detected at the fan stop and revises the temperature later when the indoor fan changes from ULo to stop. By using operation data display function at wireless remote control, the tempenature as displayad and the value is updated including the fan stops. 6) When the cooling thermostat is turned ON or the operation is changed to another mode (including stop), this control is stopped immediately, and the operating condition is restored. (v) When the “Fan OFF” is selected, the fan on the indoor unit of which the thermostat has been turned OFF, is turned OFF. The same occurs also when the remote control sensor is effective.
  • Page 57 '19 • SCM-SM-276 (11) Drain pump control (a) This control is operated when the inverter frequency is other than 0 Hz during the cooling operation and automatic cooling and dehumidifying operations. (b) Drain pump ON condition continues for 5 minutes even when it enters the OFF range according to (i) above after turning the drain pump ON, and then stops. The 5-minute delay continues also in the event of anomalous stop.
  • Page 58 '19 • SCM-SM-276 (c) Operation check mode There is no communication with the outdoor unit but it allows performing operation in respective modes by operating the remote control. (d) Drain pump test run mode As the drain pump test run is established, the drain pump only operates and during the operation protective functions by the microcomputer of indoor unit become ineffective. (14) Cooling, dehumidifying frost protection (a) To prevent frosting during cooling mode or dehumidifying mode operation, the thermostat-OFF if the indoor heat exchanger temperature (detected with Thi-R) drops to 1.0 °C or lower at 4 minutes after the thermostat-ON. If the indoor unit heat exchanger temperature is 1.0 °C or lower after 5 minutes, the indoor unit is controlled thermostat-OFF.
  • Page 59 '19 • SCM-SM-276 (17) Plural unit control – Control of 16 units group by one remote control (a) Function One remote control can control a group of multiple number of unit (Max. 16 indoor units). “Operation mode” which is set by the remote control can operate or stop all units in the group one after another in the order of unit. No. Thermostat and protective function of each unit function independently.
  • Page 60 '19 • SCM-SM-276 (19) Abnormal temperature sensor (return air/indoor heat exchanger) broken wire/short-circuit detection (a) Broken wire detection When the return air temperature sensor detects -55°C or lower or the heat exchanger temperature sensor detect -55°C or lower for 5 seconds continuously, the compressor stops. After a 3-minute delay, the compressor restarts but, if it is detected again within 60 minutes after the initial detection for 6 minutes continuously, stops again (the return air temperature sensor: E7, the heat exchanger temperature sensor: E6).
  • Page 61 '19 • SCM-SM-276 (b) Input for external control The external input for the indoor unit can be selected from the following input. Input name Content 1 Run/Stop Refer to [(20) (c) Remote operation input] 2 Premission/Prohibition Refer to [(21) Operation permission/prohibition] 3 Cooling/Heating Refer to [(23) Selection of cooling/heating external input function] 4 Emergency stop Indoor/outdoor units stop the operation, and [E63] is displayed. 5 Setting temperature shift Set temperature is shifted by +2/-2°C in cooling/heating. 6 Forced thermo-OFF Unit goes thermo off. 7 Temporary stop Refer to [(22) Temporary stop input] 8 Silent mode Outdoor unit silent mode is activated. (i) In case of “Level input” setting (Factory default) Input signal to CnT-6 or CnTA is OFF→ON …… unit ON Input signal to CnT-6 or CnTA is ON→OFF …… unit OFF Operation is not inverted.
  • Page 62 '19 • SCM-SM-276 Individual operation (Factory default) All units operation (Local setting) Only the unit Only the unit All units in one All units in one directly connected CnT-6 or directly connected remote control remote control to the remote CnTA to the remote control system can be system can be control can be can be operated.
  • Page 63 '19 • SCM-SM-276 (a) In case of CnT ① Operation stop level > CnTA ③ Operation permission/prohibition level Operation Operation Operation Stop Stop Stop Level input Operation permission Operation permission CnTA Operation prohibition Operation permission/ prohibition setting Operation Operation( ) Operation Stop Stop...
  • Page 64 '19 • SCM-SM-276 (22) Temporary stop input In case of temporary stop, operation lamp of remote control lights, but indoor/outdoor unit stop the operation. (a) In case of “level input” setting (Factory default) Input signal to CnT-6 or CnTA is OFF → ON : Temporary stop Input signal to CnT-6 or CnTA is OFF → ON : Normal operation CnT-6 or CnTA input Actual operation Temporary stop Temporary stop Remote control (b) In case of “pulse input” setting (Local setting) It is effective only when the input signal is changed OFF→ON, and “temporary stop/normal operation” is inverted.
  • Page 65 '19 • SCM-SM-276 (24) Fan control at heating startup (a) Starting conditions At the start of heating operation, if the difference of setting temperature and return air temperature is 5°C or higher after the end of hot start control, this control is performed. (b) Contents of control (i) Sampling is made at each minute and, when the indoor heat exchanger temperature (detected with Thi-R) is 37°C or higher, present number of revolutions of indoor fan speed is increased by 10min (ii) If the indoor heat exchanger temperature drops below 37°C at next sampling, present number of revolutions of indoor fan speed is reduced by 10min (c) Ending conditions Indoor fan speed is reduced to the setting air flow volume when the compressor OFF is established and at 30 minutes after the start of heating operation. (25) Room temperature detection temperature compensation during heating With the standard specification, the compressor is turned ON/OFF with the thermostat setting temperature. When the thermostat is likely to turn OFF earlier because the unit is installed at the ceiling where warm air tends to accumulate, the setting can be changed with the wired remote control indoor unit function “...
  • Page 66 '19 • SCM-SM-276 (32) Fan circulator operation (RC-EX3A only) When the fan is used for circulation, the unit is operated as follows depending on the setting with the remote control. (a) If the invalid is selected with the remote control, the fan is operated continuously during the fan operation. (normal fan mode) (b) If the valid is selected with the remote control, the fan is operated or stopped when on the difference of the remote control temperature sensor and the return air temperature sensor becomes bigger than 3°C. (33) The operation judgment is executed every 5 minutes (RC-EX3A only) Setting temperature Ts is changed according to outdoor temperature. This control is valid with cooling and heating mode. (Not auto mode) (a) Operate 5 minutes forcedly. (b) S etting temperature is adjusted every 10 minutes. (i) Cooling mode. Ts = outdoor temperature － offset value (ii) Heating mode.
  • Page 67 '19 • SCM-SM-276 (37) Motion sensor control (RC-EX3A and RCN-E2 only) The sensor determines the presence of people and the amount of activity, and the following controls are done by the motion sensor. Following settings are necessary to activate motion sensor control. (a) Infrared (motion) sensor setting: Installation setting of remote control RC-EX3A The indoor unit which is set to “Enable” become valid. TOP screen Menu  Service setting  Installation settings  Service password (b) Infrared (motion) sensor control: Energy-saving setting of remote control The function which is set to “Enable” become valid. ② Installation settings menu #2 ⑰ Infrared (motion) sensor setting Menu RC-EX3A 16:14 (Mon)
  • Page 68 '19 • SCM-SM-276 (i) Power saving / comfort control The set temperature is adjusted according to the presence of people and their amount of activity detected by the infrared (motion) sensor. MODE:AUTO/COOL/HEAT mode operation Heat Source & Activity High None Normal When the extent of human 33ºC activity is low +3ºC When the extent of human High COOL activity is high When there is no one in the None temperature...
  • Page 69 '19 • SCM-SM-276 1.3 Outdoor units 1.3.1 Outline of heating operation (1) Summary (a) Capacity control (i) Indoor unit SRK ** ZSX models only Model SCM71ZS-W SCM80ZS-W Capacity 1.1 9.4 kW 1.1 9.8 kW (ii) Indoor unit except SRK ** ZSX models Model SCM71ZS-W SCM80ZS-W...
  • Page 70 '19 • SCM-SM-276 (3) Defrost operation (a) Starting conditions satisfied (ii) finish (iii) Tho-R1 − or less (iv) The difference between the outdoor air sensor temperature (Tho-A) and outdoor heat exchanger sensor temperature (Tho-R1) is as following. Accumulated compressor operation time Accumulated compressor operation time : After 150 minutes : After 150 minutes...
  • Page 71 '19 • SCM-SM-276 1.3.2 Outline of cooling operation (1) Summary (a) Capacity control (i) Indoor unit SRK ** ZSX models only Model SCM71ZS-W SCM80ZS-W Capacity 1.8 8.8 kW 1.8 9.2 kW (ii) Indoor unit except SRK ** ZSX models Model SCM71ZS-W SCM80ZS-W Capacity...
  • Page 72 '19 • SCM-SM-276 1.3.3 Protective control function 1.3.3 Protective control function (1) Cooling overload protective control (a) Operating conditions Tho-A 41°C or more (ON1) 47°C or more (ON2) Outdoor air temperature 30 rps 30 rps Lower limit speed Outdoor air temperature ( °...
  • Page 73 '19 • SCM-SM-276 (3) Cooling low outdoor temperature protective control (a) Operating conditions When the outdoor air temperature (Tho-A) is 22°C or lower continues for 20 seconds while compressor command speed is other than 0 rps. (b) Detail of operation (i) The lower limit of compressor command speed is set to B or D rps and even if the speed becomes lower than B or D rps, the speed is kept to B or D rps. However, when the thermostat becomes OFF, the speed is reduced to 0 rps.
  • Page 74 '19 • SCM-SM-276 (5) Heating overload protective control (a) Operating conditions Tho-A (b) Detail of operation A or C B or D (ii) B or D when the thermostat OFF, the speed is (iii) B or D. (c) Reset conditions Tho-A Upper limit C Lower limit D...
  • Page 75 '19 • SCM-SM-276 (7) Refrigeration cycle system protective control (a) Starting condition This control starts when the following conditions are satisfied. (i) 　 W hen it has elapsed 30 minutes after the compressor was changed from OFF to ON in the cooling operation mode for more than 5 minutes. (ii) 　 When the compressor command speed has satisfied the following conditions. (iii) 　 W hen the indoor air temperature of running indoor unit (Th1 (Thi-A)) and the indoor heat exchanger temperature (Th2 (Thi-R1)) have satisfied the following condition even on one unit. (iv) 　 E xcept following mode • Silent mode Compressor Indoor air temperature Indoor air temperature (Th1) and indoor Unit...
  • Page 76 '19 • SCM-SM-276 (9) Compressor overheat protection Purpose (b) Detail of operation Tho-D (Example) Fuzzy 3 minutes 3 minutes 3 minutes Discharge pipe temperature (˚C) 105 115 95 105 3 minutes 95 105 3 minutes Cooling Heating Lower limit speed 20 rps 20 rps (ii)
  • Page 77 '19 • SCM-SM-276 Jumper wire (J1) Jumper wire (J2) (ii) Control value Unit: A Current safe ① Current safe ② Current safe ③ Cooling Heating Cooling Heating Cooling Heating 13.0 16.0 10.0 10.0 (11) Current cut (a) Purpose (b) Detail of operation (12) Outdoor unit failure compressor command (13) Discharge pipe sensor disconnection protection control...
  • Page 78 '19 • SCM-SM-276 (b) Once the unit is stopped by this function, it is not restarted. • Values of A, B Model SCM71ZS-W SCM80ZS-W 20 rps 20 rps 60 rps 60 rps Note (1) When the jumper wire (J32) on the outdoor unit sub-PCB is short-circuited (factory default), this control is performed only at initial operation after turning the power source on. If the jumper wire (J32) is open, this control is not performed. (14) Regulation of outdoor air flow (a) The fan operates as follows according to the compressor command speed. (Except during defrost operation.) Cooling Heating More than 31...
  • Page 79 Lower Lower Lower limit speed Lower limit speed '19 • SCM-SM-276 Outdoor air temperature > 16˚C Outdoor air temperature > 16˚C Outdoor air temperature < = 16˚C Outdoor air temperature < = 16˚C Tho-R2 Tho-R2 45°C 45°C temperature temperature Tho-R2 Tho-R2 45°C 45°C...
  • Page 80 '19 • SCM-SM-276 (20) Limit of the number of compressor starts Maximum number of compressor starts is limited to 6 times per hour by cutting jumper wire (JA31) on the outdoor unit sub PCB. JA33 JA34 JA32 JA35 JA31 JA36 Jumper wire JA31...
  • Page 81 '19 • SCM-SM-276 2. MAINTENANCE DATA 2.1 SRK and SRR series (1) Cautions (1) Cautions (2) Items to check before troubleshooting (2) Items to check before troubleshooting source source (3) Troubleshooting procedure (If the air-conditioner does not run at all) (3) Troubleshooting procedure (If the air-conditioner does not run at all) satisfied satisfied...
  • Page 82 '19 • SCM-SM-276 (4) Troubleshooting procedure (If the air-conditioner runs) 82−88. 82−88.
  • Page 83 '19 • SCM-SM-276 (5) Self-diagnosis table Models SCM71, 80 Wired Outdoor Indoor unit display panel remote Description main PCB Cause Display (flashing) condition control TIMER of trouble Red LED display light light When a heat exchanger temperature sensor 1 wire disconnection is detected •...
  • Page 84 '19 • SCM-SM-276 (6) Service mode (Trouble mode access function) (a) Explanation of terms Explanation Term The service mode is the mode where service data are displayed by flashing of the display lights Service mode when the operations in item (b) below are performed with the indoor control. These are the contents of error displays and protective stops which occurred in the past in the air- conditioner system.
  • Page 85 '09•SRK-DB-087D '19 • SCM-SM-276 4-time flash 2-time flash. wireless mode mode Self-diagnosis data data? wireless mode mode Wireless remote control setting Contents of output data Operation mode Fan speed mode wireless Indicates the number of Wireless remote control setting occasions previous to the present Temperature setting the error display data are from.
  • Page 86 '09•SRK-DB-087D '19 • SCM-SM-276 (Example) Wireless remote control setting Operation Displayed data Fan speed Temperature mode mode setting Displays the reason for the stop (error code) the previous time an error was displayed. 21ºC Displays the reason for the stop (error code) 2 times previous when an error was displayed. 22ºC Cooling 23ºC...
  • Page 87 '19 • SCM-SM-276 (c) Error code, stop code table Number of flashes when in service mode Stop coad Error Auto TIMER Error content Cause Occurrence conditions display recovery light light Error coad (10's digit) (1's digit) Normal The wired remote control wire Y is open. The wired remote Error of wired remote control Broken wired remote control wire, 1-time...
  • Page 88 '09•SRK-DB-087D '19 • SCM-SM-276 4-time flash 2-time flash. (d) Operation mode, Fan speed mode information tables (ii) mode mode Display pattern when Display pattern when Fan speed in service mode in service mode Operation mode mode when when there is an there is an RUN light TIMER light...
  • Page 89 '09•SRK-DB-087D '19 • SCM-SM-276 (e) Temperature information Room temperature sensor, indoor heat exchanger temperature sensor, outdoor air temperature sensor, outdoor heat exchanger temperature sensor temperature Unit: °C TIMER light (1’s digit) RUN light (10’s digit) Buzzer sound (sounds for 0.1 second) (does not sound) temperature information Sensor value displayed when the error code is normal...
  • Page 90 '09•SRK-DB-087D '19 • SCM-SM-276 (ii) Discharge pipe temperature sensor temperature Unit: °C TIMER light (1’s digit) RUN light (10’s digit) Buzzer sound (sounds for 0.1 second) (does not sound) temperature information Sensor value displayed when the error code is normal -64ºC temperature data...
  • Page 91 '09•SRK-DB-087D '19 • SCM-SM-276 Service data record form Wireless r Operation mode Fan speed mode temperature Wireless r temperature temperature temperature temperature Wireless r temperature temperature temperature temperature Wireless r temperature temperature temperature temperature Wireless r temperature temperature temperature temperature Wireless r temperature temperature...
  • Page 92 '19 • SCM-SM-276 (7) Inspection procedures corresponding to detail of trouble Sensor error Broken sensor wire, connector poor connection Discharge pipe and power transistor sensor Sensor temperature characteristics Room temperature, indoor heat exchanger tempe- temperature characteristics rature, outdoor heat exchanger temperature, outdoor air temperature outdoor suction pipe temperature - 10...
  • Page 93 '19 • SCM-SM-276 Limit switch anomaly (SRK20, 25, 35, 50, 60ZSX-W only) Defective limit switch, defective indoor unit control PCB, Defective air inlet panel set Is the air inlet panel set correctly? Correction, re-set Are limit switch OK ? Defective limit switch Note(1) Check if the limit switch functions properly or not by seeing whether the lamp continues to blink or can be reset by pressing the limit swit- ch by hand while the air inlet panel is removed.
  • Page 94 '19 • SCM-SM-276 Over heat of compressor Gas shortage, defective discharge pipe temperature sensor temperature temperature unit main Error of signal transmission Wiring error including power cable, defective indoor/ outdoor unit PCB ② ③ indoor unit ② ③ indoor unit ①...
  • Page 95 '19 • SCM-SM-276 Trouble of outdoor unit Insuf cient refregerant amount, Faulty power transistor, Broken compressor wire Service valve close, Defective EEV, Defective outdoor unit PCB source source source source − − − unit sub ◆  unit (1)  main    ...
  • Page 96 '19 • SCM-SM-276 Rotor lock Defective compressor, defective outdoor unit PCB unit main See page 91. Drain abnormality (SRR only) [Drain piping defective,pump defect, float switch, indoor unit PCB] Indoor unit PCB Has an overflow developed? Is the float switch operating? is defective.
  • Page 97 '19 • SCM-SM-276 (8) Phenomenon observed after short-circuit, wire breakage on sensor (a) Indoor unit Phenomenon Operation Sensor mode Shortcircuit Disconnected wire Cooling Room temperature sensor Heating Freezing cycle system protection trips and stops the compressor. Cooling Heat exchanger temperature sensor Heating Cooling Humidity sensor...
  • Page 98 Cooling Heat exchanger sensor Heating Defrosting is performed for 10 minutes at approx. 40 minutes. Cooling Ourdoor air '19 • SCM-SM-276 temperature sensor Defrosting is performed for 10 minutes at approx. 40 minutes. Heating Discharge pipe All modes sensor (9) Checking the indoor electrical equipment (a) Indoor unit PCB check procedure Is there voltage between terminal Inspect power source...
  • Page 99 Operation SW ON Measure in this section '19 • SCM-SM-276 (10) How to make sure of wireless remote control wireless wireless wireless wireless wireless wireless   Simplified check method of wireless remote control It is normal if the signal transmission section of the wireless remote control emits a whitish light at each transmission on the monitor of digital camera.
  • Page 100 '19 • SCM-SM-276 (12) Outdoor unit inspection points Models SCM71ZS-W,80ZS-W Color marks Mark Color Black CAUTION- HIGH VOLTAGE ◆Power source and serial signal inspection Blue ① to ②: AC 220/230/240V Brown High voltage is produced in the control box. Don't touch ②...
  • Page 101 '19 • SCM-SM-276 (a) Inspection of electronic expansion valve   (ii) (iii) unit sub (iv) • Inspection of electronic expansion valve as a separate unit Measuring point Resistance when normal (b) Outdoor fan motor check procedure main (i) Outdoor unit main PCB output check   ...
  • Page 102 '19 • SCM-SM-276 2.2 FDTC, FDUM and FDE series 2.2.1 Diagnosing of microcomputer circuit Selfdiagnosis function (a) Check indicator table Whether a failure exists or not on the indoor unit and outdoor unit can be know by the contents of remote control error code, indoor/outdoor unit green LED (power pilot lamp and microcomputer normality pilot lamp) or red LED (check pilot lamp).
  • Page 103 '19 • SCM-SM-276 (ii) Outdoor unit Outdoor Remote control Indoor control PCB Reference main PCB Location of trouble Description of trouble Repair method page Green Error code Red LED Red LED Red LED Installation, operation status • Higher outdoor heat exchanger temperature Repair Replacement, repair Outdoor heat exchanger...
  • Page 104 '19 • SCM-SM-276 (iii) Display sequence of error codes or inspection indicator lamps ■ Occurrence of one kind of error Displays are shown respectively according to errors. ■ Occurrence of plural kinds of error Section Category of display Error code on remote control •...
  • Page 105 '19 • SCM-SM-276 ■ Error log and reset Error indicator Memorized error log Reset Remote control display • Higher priority error is memorized. • Stop the unit by pressing the ON/OFF switch of remote control. Red LED on indoor unit control PCB •...
  • Page 106 '19 • SCM-SM-276 FDTC series PSC012D050 Replace and set up the PCB according to this instruction. 1) Set to an appropriate address and function using switch on PCB. Select the same setting with the removed PCB. Item Switch Content of control Address Plural indoor units control by 1 remote control Normal...
  • Page 107 '19 • SCM-SM-276 (ii) Models FDUM, FDE series 1) Control PCB PSB012D990B Replace and set up the PCB according to this instruction. a) Set to an appropriate address and function using switch on PCB. Select the same setting with the removed PCB. item switch Content of control...
  • Page 108 '19 • SCM-SM-276 2) Power PCB This PCB is a general PCB. Replace the PCB according to this instruction. a) Replace the PCB ① Unscrew terminal of the wiring(yellow/green) connected to terminal block (CNWO) from the box. ② Replace the PCB only after all the wirings connected to the connector are removed. ③...
  • Page 109 '19 • SCM-SM-276 Troubleshooting at the outdoor unit When troubleshooting the outdoor unit, firstly assess the overview of malfunction and try to presume the cause and the faulty part by checking the error code dispalyed on the remote control and then proceed further inspection and remedy Self-diagnosis system by microcomputor on indoor unit PCB can assist to find the cause of malfunction smoothly by making a diagnosis of not only the anomaly of microcomputer, but also the anomaly in power source system, installation space, overload resulting from improper charging amount of refrigerant and etc.
  • Page 110 '19 • SCM-SM-276 (5) Check of anomalous operation data with the remote control (a) In case of RC-EX3A remote control [Operating procedure] ➀ On the TOP screen, touch the buttons in the order of “Menu” ➝ “Service setting” ➝ “Service & Maintenance” ➝ “Service password”...
  • Page 111 '19 • SCM-SM-276 (b) In case of RC-E5 remote control Data Item Number Operation data can be checked with remote control unit operation. (Operation Mode) (Set Temperature) ➀ Press the button. (Return Air Temperature) The display change “ ” (Remote Control Temperature) ➁...
  • Page 112 '19 • SCM-SM-276 Inverter checker for diagnosis of inverter output 　 ●Checking method (a) Setup procedure of checker. Power OFF (Turn off the breaker). (ii) Remove the terminal cover of compressor and disconnect the wires (U, V, W) from compressor. (iii) Connect the wires U (Red) , V (White) and W (Black) of the checker to the terminal of disconnected wires (U, V, W) from compressor respectively.
  • Page 113 '19 • SCM-SM-276 2.2.2 Troubleshooting flow (1)　List of troubles Remote control display Description of trouble Reference page None Operates but does not cool None Operates but does not heat None Earth leakage breaker activated None Excessive noise/vibration 115−117 None Louver motor failure (FDTC and FDE only) None Power source system error (Power source to indoor unit control PCB) None...
  • Page 114 '19 • SCM-SM-276 (2) Troubleshooting Green Error code Content Indoor Keeps flashing Stays OFF Remote control: None Operates but does not cool Outdoor – Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Check the indoor fan operation. Check the temperature differnce between return and supply air.
  • Page 115 '19 • SCM-SM-276 Green Error code Content Indoor Keeps flashing Stays OFF Remote control: None Operates but does not heat – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Check the indoor fan operation. Check the temperature differnce between return and supply air.
  • Page 116 '19 • SCM-SM-276 Green Error code Content Indoor Stays OFF Stays OFF Remote control: None Earth leakage breaker activated – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Are OK the insulation resistance and resistance Replace compressor. between terminals (1) of compressor? (1) See page 145.
  • Page 117 '19 • SCM-SM-276 Green Error code Content Indoor – – Remote control: None Excessive noise/vibration (1/3) – – Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure If excessive noise/vibration persists when sufficient Does time has elapsed after noise/vibration stopping the unit, it is occur during or soon after stopping operation...
  • Page 118 '19 • SCM-SM-276 Green Error code Content Indoor – – Remote control: None Excessive noise/vibration (2/3) – – Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure From previous page Rearrange the piping to Are the pipes avoid contact with the contacting the casing.
  • Page 119 '19 • SCM-SM-276 Green Error code Content Indoor – – Remote control: None Excessive noise/vibration (3/3) – – Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure From previous page If insufficient cooling/ Adjustment heating problem happens during commissioning due to anomalous operating Does noise/vibration occur when the conditions at cooling/...
  • Page 120 '19 • SCM-SM-276 Green Error code Content Louver motor failure Indoor Keeps flashing Stays OFF Remote control: None (FDTC and FDE only) – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model FDTC and FDE series only Diagnosis Countermeasure ▲ Check at the indoor unit side. Operate after waiting for more than 1 minute.
  • Page 121 '19 • SCM-SM-276 Green Error code Content Power source system error Indoor Stays OFF Stays OFF Remote control: None (Power source to indoor unit control PCB) – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure AC220/240V detected between on the terminal block of indoor...
  • Page 122 '19 • SCM-SM-276 Green Error code Content Power source system error Indoor Keeps flashing 3-time flash Remote control: None (Power source to remote control) – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the connection of the Correct.
  • Page 123 '19 • SCM-SM-276 Green Error code Content INSPECT I/U Indoor Keeps flashing Stays OFF Remote control: INSPECT I/U (When 1 or 2 remote controls are connected) – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Are 2 units of remote control connected? ⑴，...
  • Page 124 '19 • SCM-SM-276 Green Error code Content INSPECT I/U Indoor Keeps flashing Stays OFF Remote control: INSPECT I/U (Connection of 3 units or more remote controls) – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Are more than Reduce to 2 units or less.
  • Page 125 '19 • SCM-SM-276 Green Error code Content Communication error at Indoor Keeps flashing Stays OFF Remote control: WAIT initial operation (1/3) – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All Models Diagnosis Countermeasure When the remote control LCD displays “ ”...
  • Page 126 '19 • SCM-SM-276 Green Error code Content Communication error at Indoor Keeps flashing Stays OFF Remote control: WAIT initial operation (2/3) – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All Models Diagnosis Countermeasure When the fuse is blown, the method to inspect outdoor sub PCB before replacing the power Is there a...
  • Page 127 '19 • SCM-SM-276 Green Error code Content Communication error at Indoor Keeps flashing Stays OFF Remote control: WAIT initial operation (3/3) – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All Models Diagnosis Countermeasure When the remote control display is extinguished after the power on.
  • Page 128 '19 • SCM-SM-276 Green Error code Content Stays OFF Stays OFF Indoor No display Remote control: None – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Remote control does not display anything after the power on. Is DC10V or Defective remote control.
  • Page 129 '19 • SCM-SM-276 Green Error code Content Remote control Keeps flashing Stays OFF Indoor Remote control: communication circuit error – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Malfunction by noise Is it possible to Check peripheral reset normally by the power reset? environment.
  • Page 130 '19 • SCM-SM-276 Green Error code Content Indoor Keeps flashing 2-time flash Remote control: Communication error during operation Outdoor – 6-time flash 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Note (1) Inspect faulty connections (disconnection, looseness) on the outdoor unit terminal block. Is the connection of signal Repair signal wires.
  • Page 131 '19 • SCM-SM-276 Green Error code Content Indoor heat exchanger Indoor Keeps flashing 1-time flash Remote control: temperature sensor anomaly – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the connection of indoor heat Correct. ➞ Insert connector exchanger temperature sensor securely.
  • Page 132 '19 • SCM-SM-276 Green Error code Content Return air temperature Indoor Keeps flashing 1-time flash Remote control: sensor anomaly – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the connection of return Correct. ➞ Connect air temperature sensor connector.
  • Page 133 '19 • SCM-SM-276 Green Error code Content Indoor Keeps flashing 1-time flash Remote control: Heating overload operation – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the air filter clogged? Wash. 2. Error detection method Is the indoor heat exchanger Defective indoor heat...
  • Page 134 '19 • SCM-SM-276 Green Drain trouble Error code Content Keeps flashing 1-time flash Indoor Remote control: (FDTC and FDUM only) – Stays OFF Outdoor 5. Troubleshooting 1. Applicable model FDTC and FDUM series only Diagnosis Countermeasure Check the error data in the remote control. Is there any overflow? Is DC12V at CNI connector.
  • Page 135 '19 • SCM-SM-276 Excessive number of connected Green Error code Content indoor units (more than 17 units) Indoor Keeps flashing Stays OFF Remote control: by controlling with one remote control – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Are more than 17...
  • Page 136 '19 • SCM-SM-276 Green Green Error code Error code Content Content Address setting error of Indoor Indoor Keeps flashing Keeps flashing Remote control: Remote control: indoor units – Outdoor Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure E11 occurs Is “Master IU...
  • Page 137 '19 • SCM-SM-276 Green Error code Content Indoor fan motor anomaly Indoor Keeps flashing 1-time flash Remote control: – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Does any foreign material Remove foreign material. intervene in rotational area of fan propeller? Does the fan 2.
  • Page 138 '19 • SCM-SM-276 Green Error code Content Indoor unit operation check, Indoor Keeps flashing 1-time flash Remote control: drain pump moter check setting error – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure E19 occurs when the power ON Is SW7-1 Defective indoor unit on the indoor unit control...
  • Page 139 '19 • SCM-SM-276 Green Error code Content Indoor fan motor rotation Indoor Keeps flashing 1-time flash Remote control: speed anomaly – Outdoor Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Does any foreign material Remove foreign material. intervene in rotational area of fan propeller? Does the fan...
  • Page 140 '19 • SCM-SM-276 Green Error code Content Remote control Indoor Keeps flashing Stays OFF Remote control: temperature sensor anomaly Outdoor – Stays OFF 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the remote Correct. control temperature sensor connected properly? 2.
  • Page 141 '19 • SCM-SM-276 Green Error code Content Indoor Keeps flashing Stays OFF Cooling high pressure operation Remote control: – 2-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure * For the characteristics of outdoor heat exchanger temperature Are normal sensor, refer to E37.
  • Page 142 '19 • SCM-SM-276 Green Error code Content Discharge pipe Indoor Keeps flashing Stays OFF temperature error Remote control: Outdoor – 5-time flash 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure * For the characteristics of discharge Are the pipe temperature, refer to E39. characteristics of Replace discharge pipe discharge pipe temperature...
  • Page 143 '19 • SCM-SM-276 Green Error code Content Outdoor heat exchanger Indoor Keeps flashing Stays OFF Remote control: temperature sensor anomaly – 8-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the outdoor heat exchanger temperature Correct connector. sensor connector connected properly?
  • Page 144 '19 • SCM-SM-276 Green Green Error code Error code Content Content Outdoor air temperature Indoor Indoor Keeps flashing Stays OFF Remote control: Remote control: sensor anomaly Outdoor Outdoor – 8-time flash 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure the outdoor air Correct connector.
  • Page 145 '19 • SCM-SM-276 Green Error code Content Discharge pipe Indoor Keeps flashing Stays OFF Remote control: temperature sensor anomaly – 8-time flash Outdoor 5. Troubleshooting 1. Applicable model Diagnosis Countermeasure All models Is the discharge pipe temperature sensor Correct connector. connector connected properly? 2.
  • Page 146 '19 • SCM-SM-276 Green Error code Content Service valve (gas side) closing operation Indoor Keeps flashing Stays OFF Remote control: – 4-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Are the Open the service valve. service valve (gas side) opened? 2.
  • Page 147 '19 • SCM-SM-276 Green Error code Content Indoor Keeps flashing Stays OFF Current cut (1/2) Remote control: – 1-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the Power source Check power source. voltage OK? 2. Error detection method Are the Open the valves.
  • Page 148 inverter PCB 1-time flash '19 • SCM-SM-276 Green Error code Content Indoor Keeps flashing Stays OFF Current cut (2/2) Remote control: – 1-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure From previous page Is the checked result of power Defective outdoor unit transistor module main PCB ➞...
  • Page 149 '19 • SCM-SM-276 Green Error code Content Outdoor unit sub PCB Indoor Keeps flashing Stays OFF Remote control: communication error – 4-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the connector connection between the outdoor unit Correct connector.
  • Page 150 '19 • SCM-SM-276 Green Green Error code Error code Content Content Indoor Indoor Keeps flashing Stays OFF Remote control: Remote control: Active filter voltage error – 2-time flash Outdoor Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Restore normal condition. Is the power source normal? 2.
  • Page 151 '19 • SCM-SM-276 Green Error code Content Outdoor fan motor anomaly Indoor Keeps flashing Stays OFF Remote control: – Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Does any foreign material intervene Remove foreign matter. in rotational area of fan propeller? Does the 2.
  • Page 152 '19 • SCM-SM-276 Green Green Error code Content Content Error code Power transistor error Power transistor anomaly Indoor Keeps flashing Stays OFF Remote control: Remote controller: E51 Keeps flashing Stays Off Indoor (Models SRC50, 60) – 1-time flash Outdoor 5. Troubleshooting 1.
  • Page 153 '19 • SCM-SM-276 Green Error code Content Suction pipe temperature Indoor Keeps flashing Stays OFF Remote control: sensor anomaly – 8-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure the suction pipe Correct connector. temperature sensor connector connected properly? For the characteristics of suction pipe temperature sensor, see the following graph.
  • Page 154 '19 • SCM-SM-276 Green Error code Content Insufficient refrigerant amount Indoor Keeps flashing Stays OFF Remote control: or detection of service valve closure – 2-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the Open fully. service valve fully opened? Are the...
  • Page 155 '19 • SCM-SM-276 Green Green Error code Content Error code Content Current safe stop Current safe stop Indoor Keeps flashing Stays Off Indoor Keeps flashing Stays OFF Remote controller: E58 Remote control: (Model SRC50, 60) Outdoor 3 time flash – 3-time flash Outdoor ―...
  • Page 156 '19 • SCM-SM-276 Green Error code Content Compressor startup failure Indoor Keeps flashing Stays OFF Remote control: – 2-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Disconnect the outdoor fan motor Compressor does not start at all. connector and try to startup.
  • Page 157 '19 • SCM-SM-276 Green Error code Content Compressor rotor lock error Indoor Keeps flashing Stays OFF Remote control: – 7-time flash Outdoor 5. Troubleshooting 1. Applicable model All models Diagnosis Countermeasure Is the Check and correct the power source voltage power source voltage.
  • Page 158 '19 • SCM-SM-276 3. ELECTRICAL WIRING (1) Outdoor unit Models SCM71ZS-W, 80ZS-W RWC000Z331...
  • Page 159 '19 • SCM-SM-276 (2)　Indoor unit (a) 　 Wall mounted type (SRK) (i)　Models SRK20ZSX-W, 25ZSX-W, 35ZSX-W, 50ZSX-W, 60ZSX-W SRK20ZSX-WB, 25ZSX-WB, 35ZSX-WB, 50ZSX-WB, 60ZSX-WB SRK20ZSX-WT, 25ZSX-WT, 35ZSX-WT, 50ZSX-WT, 60ZSX-WT RWA000Z413...
  • Page 160 '19 • SCM-SM-276 (ii)　Models SRK20ZS-W, 25ZS-W, 35ZS-W, 50ZS-W SRK20ZS-WB, 25ZS-WB, 35ZS-WB, 50ZS-WB SRK20ZS-WT, 25ZS-WT, 35ZS-WT, 50ZS-WT RWA000Z416...
  • Page 161 '19 • SCM-SM-276 (iii)　Model SRK71ZR-W RWA000Z417...
  • Page 162 '19 • SCM-SM-276 (b)　Ceiling concealed type (SRR) 　 Models SRR25ZM-W, 35ZM-W, 50ZS-W, 60ZS-W RJJ000Z003...
  • Page 163 '19 • SCM-SM-276 (c)　4-way ceiling cassette type (FDTC) 　 Models FDTC25VH, 35VH, 50VH, 60VH PJF000Z516...
  • Page 164 '19 • SCM-SM-276 (d)　Duct connected-Low / Middle static pressure type (FDUM) 　 Model FDUM50VH PJG000Z488...
  • Page 165 '19 • SCM-SM-276 (e)　Ceiling suspended type (FDE) 　 Model FDE50VH PFA004Z087...
  • Page 166 '19 • SCM-SM-276 4. PIPING SYSTEM Models SCM71ZS-W, 80ZS-W...
  • Page 167 MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD. 2-3, Marunouchi 3-chome, Chiyoda-ku, Tokyo, 100-8332, Japan http://www.mhi-mth.co.jp/en/ Because of our policy of continuous improvement, we reserve the right to make changes in all specifications without notice. Copyright MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD.

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