Mitsubishi Heavy Industries FDT28KXE6A User manual

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1
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Manual No. '09·KX-SM -128
INVERTER DRIVEN MULTI-INDOOR UNIT
CLIMATE CONTROL SYSTEM
SERVICE MANUAL
Alternative refrigerant R410A use models
(OUTDOOR UNIT)
• Single use (Used also for combination)
FDC335KXE6-K, 400KXE6, 450KXE6, 504KXE6, 560KXE6, 560KXE6-K, 615KXE6, 680KXE6
• Combination use
FDC753KXE6, 800KXE6, 850KXE6, 900KXE6, 960KXE6, 1010KXE6, 1065KXE6, 1130KXE6,
1180KXE6, 1235KXE6, 1300KXE6, 1360KXE6
(Heat pump type)
KX6 series
FDT28KXE6A
36KXE6A
45KXE6A
56KXE6A
71KXE6A
90KXE6A
112KXE6A
140KXE6A
160KXE6A
FDUM22KXE6
28KXE6
36KXE6
45KXE6
56KXE6
71KXE6
90KXE6
112KXE6
140KXE6
FDUH22KXE6
28KXE6
36KXE6
FDTC22KXE6A
28KXE6A
36KXE6A
45KXE6A
56KXE6A
FDQS22KXE6
28KXE6
36KXE6
45KXE6
56KXE6
FDU71KXE6
90KXE6
112KXE6
140KXE6
224KXE6
280KXE6
FDFU28KXE6
45KXE6
56KXE6
71KXE6
FDTW28KXE6
45KXE6
56KXE6
71KXE6
90KXE6
112KXE6
140KXE6
FDK22KXE6
28KXE6
36KXE6
45KXE6
56KXE6
71KXE6
FDTQ22KXE6
28KXE6
36KXE6
FDFL28KXE6
45KXE6
71KXE6
FDTS45KXE6
71KXE6
FDE36KXE6A
45KXE6A
56KXE6A
71KXE6A
112KXE6A
140KXE6A
(INDOOR UNIT) - KX6 series -
Regarding the Duct Connected-High static Pressure-type Outdoor Air Processing
Unit Series (FDU500〜1800FKXE6), refer to the DATA BOOK No.'08
• KX-DB-122
• Note
updated November 19, 2009

CONTENTS
1 OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER..................... 1
1.1 Wired remote controller (Option parts)...................................................... 1
1.2 Operation control function by the indoor controller ...................................2
1.3 Operation control function by the remote controller ..................................8
1.4 Operation control function by the outdoor controller.................................9
2 SYSTEM TROUBLESHOOTING PROCEDURE............................................. 45
2.1 Basics of troubleshooting........................................................................ 45
2.2 Explanation of troubleshooting................................................................46
2.3 Contents of troubleshooting....................................................................47
2.4 Outdoor unit control PCB replacement procedure ................................101
2.5 Inverter PCB replacement procedure.................................................... 103
3 ELECTRICAL WIRING .................................................................................. 107
3.1 Indoor unit ............................................................................................. 107
3.2 Outdoor unit .......................................................................................... 129
4 PIPING SYSTEM............................................................................................ 130
5 APPLICATION DATA.................................................................................... 131
5.1 Installation of indoor unit........................................................................... 131
(a) Ceiling cassette-4 way type (FDT)..................................................... 132
(b) Ceiling cassette-4 way compact type (FDTC)....................................137
(c) Ceiling cassette-2 way type (FDTW) ................................................. 142
(d) Ceiling cassette-1 way type (FDTS) .................................................. 145
(e) Ceiling cassette-1 way compact type (FDTQ) ................................... 148
(f) Duct connected-High static pressure type (FDU) .............................. 151
(g) Duct connected-Middle static pressure type (FDUM)........................157
(h) Duct connected (Ultra thin)-Low static pressure type (FDQS)........... 160
(i) Wall mounted type (FDK) ..................................................................163
(j) Ceiling suspended type (FDE)........................................................... 166
(k) Floor standing (with casing) type (FDFL)........................................... 169
(l) Floor standing (without casing) type (FDFU).....................................172
(m) Duct Connected-Compact and Flexible type (FDUH)........................ 175
5.2 Electric wiring work instruction.................................................................. 178
5.3 Installation manual of wired remote controller (Option parts)...................184
5.4 Installation of outdoor unit.........................................................................188
5.5 Instructions for installing the branch pipe set............................................211

– 1–
1. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER
1.1 Wired remote controller (Option parts)
The gure below shows the remote controller with the cover opened. Note that all the items that may be displayed in the liquid crystal
display area are shown in the gure for the sake of explanation.
Characters displayed with dots in the liquid crystal display area are abbreviated.
Pull the cover downward to open it.
＊ All displays are described in the liguid crystal display for explanation.
The figure below shows the remote control with the cover opened.
Installation of remote control
DO NOT install it on the following places in order to avoid malfunction.
(1) Places exposed to direct sunlight
(2) Places near heat devices
(3) High humidity places
(4) Hot surface or cold surface enough to generate condensation
(5) Places exposed to oil mist or steam directly
(6) Uneven surface
Cover
This button is used to fix the setting.
This button is used to set the silent mode.

– 2–
1.2 Operation control function by the indoor controller
(1) Operations of functional items during cooling/heating
Cooling Heating
Dehumidify
Fan
Operation
Functional item
Thermostat
ON Thermostat ON
Thermostat
OFF Thermostat OFF Hot start (Defrost)
Compressor
4-way valve
Outdoor fan
Indoor fan
Louver motor
Drain pump (4)











/
(2)




(2)




/ 
/




/ 
/
/(2)

()
()

/ 
/
/

/
/
/
Thermostat ON: 
Thermostat OFF: (2)
Note (1) : Operation : Stop /: Turned ON/OFF by the control other than the room temperature control.
(2) ON during the drain motor delay control
(3) Drain pump ON setting may be selected by the indoor unit function setting of the wired remote controller.
(2) Dehumidifying operation
(a) When the humidity sensor is not provided (Models other than FDT Series)
return air thermistor [ThI-A (by the remote controller when the remote control sensor is enabled)] controls the indoor
temperature environment simultaneously.
1) Operation is started in the cooling mode. When the difference between the return air thermistor and the setting
temperature is 2°C or less, the indoor unit fan tap is brought down by one tap. That tap is retained for 3 minutes
after changing the indoor fan tap.
2) If the suction air temperature exceeds the setting temperature 3°C or more during defrosting operation, the indoor
fan tap is raised by one tap. That tap is retained for 3 minutes after changing the indoor fan tap.
3) If the thermostat OFF is established during the above control, the indoor fan tap at the thermostat ON is retained so
far as the thermostat is turned OFF.
4) After stopping the cooling operation, the indoor unit continues to run at Lo for 15 seconds.
(b) When the humidity sensor is provided (FDT Series only) [Optional]
1) Operation starts in the cooling mode, and the target relative humidity is determined based on the setting temperature.
If the humidity detected by the humidity sensor becomes lower than the target relative humidity, the indoor unit fan
tap is retained.
2) Anything other than 1) above is same as the item (a) above.
(3) Timer operation
(a) Timer
Set the duration of time from the present to the time to turn off the air-conditioner.
It can be selected from 10 steps in the range from “OFF 1 hour later” to “OFF 10 hours later”. After the clock timer
setting, the remaining time is displayed with progress of time in the unit of hour.
(b) OFF timer
Time to turn OFF the air-conditioner can be set in the unit of 10 minutes.
(c) ON timer
Time to turn ON the air-conditioner can be set. Indoor temperature can be set simultaneously.
(d) Weekly timer
Timer operation (ON timer, OFF timer) can be set up to 4 times a day for each weekday.
(e) Timer operations which can be set in combination
Timer
OFF timer
ON timer
Weekly timer
Timer



OFF timer



ON timer



Weekly timer



Note (1) : Allowed : Not

– 3–
(4) Remote controller display during the operation stop
(a) “Centralized control ON” is displayed always on the LCD under the “Center/Remote” and “Center” modes during the
operation stop (Power ON). This is not displayed under the “Remote” mode.
(b) If this display is not shown under the “Center/Remote” mode, check if the indoor unit power switch is turned on or not.
(5) Hot start (Prevention of cold draft during heating)
At the startup of heating operation, at resetting the thermostat, during defrosting operation and at returning to heating, the
indoor fan is controlled by the indoor heat exchanger temperature (detected with ThI-R) to prevent the cold draft.
Judgment by heating start thermostat
Normal condition/Set airflow volume
Thermostat OFF Thermostat ON
Compressor OFFCompressor ON End of defrosting
Heat exchanger temp. 35˚C or higher, or after 7 minutes Heat exchanger temp. 35˚C or higher, or after 7 minutes
Defrosting start
Fan
Lo
Lo
Set airflow volume
Set airflow volume
Indoor heat exchanger temp. (˚C)
Indoor heat exchanger temp. (˚C)
35
35 45
25 35
Indoor heat exchanger temp. (˚C)
Set airflow volume
Fan
OFF
Lo
25 35 45
Set airflow volume
Fan
OFF
Indoor heat exchanger temp. (˚C)
Fan
Lo
（1）
Note (1) Heating preparation is displayed during the hot start (when the compressor is operating and the indoor fan does not provide the set airow volume).
(6) Hot keep
Hot keep control is performed at the start of the defrost control.
(a) Control
1) When the indoor heat exchanger temperature (detected with ThI-R1 or R2) drops to 35°C or lower, indoor fan is
changed to the lower tap at each setting.
2) During the hot keep operation, the louver horizontal control signal is transmitted.
(b) Ending condition
When the indoor fan is at the lower tap at each setting, it returns to the set airow volume as the indoor heat exchanger
temperature rises to 45°C or higher.
(7) Fan control during the heating thermostat OFF
When the heating thermostat is turned OFF, the setting of the fan control is selectable with using the indoor function of wired
remote controller [Heating fan control].
(a) Low speed (Factory default)
If the indoor heat exchanger temperature drops 35°C or lower with the heating thermostat OFF, the indoor fan operate at
the lower speed tap at each setting.
(b) Set airow volume
Even if the indoor heat exchanger temperature drops 35°C or lower with the heating thermostat OFF, the indoor fan
continues to run at the set airow volume.
(c) Intermittent operation
If the indoor heat exchanger temperature drops 35°C or lower with the heating thermostat OFF, the indoor fan operates at
the lower speed tap at each setting and, when the indoor heater exchanger temperature drops 25°C or lower, the indoor fan
stops for 5 minutes. Then the fan runs at the slow speed tap for 2 minutes, and the judgment is made by the thermostat.
(d) Stop
If the indoor heat exchanger temperature drops 35°C or lower with the heating thermostat OFF, the indoor fan is turned
OFF. The same applies also when the remote controller sensor is effective.

– 4–
(8) Filter sign
As the operation time (when ON/OFF switch is at ON) accumulates to 180 hours (1), “Filter cleaning” is displayed on the
remote controller. (This is also displayed when the unit is in trouble and under the centralized control, regardless of ON/OFF)
Note (1) Time setting for the lter sign can be made as shown below using the indoor function of wired remote controller “Filter sign setting”. (It is set at 1 at the
shipping from factory.)
Filter Sign Setting
Setting 1
Setting 2
Setting 3
Setting 4
Function
Setting time: 180 hrs (Factory default)
Setting time: 600 hrs
Setting time: 1,000 hrs
Setting time: 1,000 hrs (Unit stop)
(2)
(2) After the setting time has elapsed, the “Filter cleaning” is displayed and, after operating for 24 hours further (counted also during the stop), the unit stops.
(9) Auto swing control [Applicable model: FDT, FDTC, FDTW, FDTS, FDTQ (Excepted duct panel model) FDK
and FDE]
(a) Louver control
(i) Press the [Louver] button to operate the swing louver when the air conditioner is operating.
“Auto wind direction” is displayed for 3 seconds and then the swing louver moves up and down continuously.
(ii) To x the swing louver at a position, press one time the [Louver] button while the swing louver is moving so that
four stop positions are displayed one after another per second.
When a desired stop position is displayed, press the [Louver] button again. The display stops, changes to show the
“Louver stop” for 5 seconds and then the swing louver stops.
(iii) Louver operation at the power on
The louver swings one time automatically (without operating the remote controller) at the power on.
This allows inputting the louver motor (LM) position, which is necessary for the microcomputer to recognize the
louver position.
Note (1) If you press the Louver button, the swing motion is displayed on the louver position LCD for 10 second. The display changes to the “Auto wind
direction” display 3 seconds later.
(b) Automatic louver level setting during heating
While hot start operation and heating thermostat OFF operation, the louver keeps the level position (In order to prevent
the cold draft) whether the auto swing switch is operated or not (auto swing or louver stop), The louver position display
LCD continues to show the display which has been shown before entering this control.
(c) Louver-free stop control
When the louver-free stop has been selected with the indoor function of wired remote controller “Louver control setting”,
the louver motor stops when it receives the stop signal from the remote controller. If the auto swing signal is received
from the remote controller, the auto swing will start from the position where it was before the stop.
Note (1) When the indoor function of wired remote controller “Louver control setting” has been switched, switch also the remote control function “Louver
control setting” in the same way.
(10) Compressor inching prevention control
(a) 3-minutes timer
When the compressor has been stopped by the thermostat, remote controller operation switch or anomalous condition, its
restart will be inhibited for 3 minutes. However, the 3-minute timer is invalidated at the power on.
(b) 3-minutes forced operation timer
• Compressor will not stop for 3 minutes after the compressor ON. However, it stops immediately when the thermostat is
turned OFF by the stop command by means of the ON/OFF switch or the change of operation mode.
• If the thermostat is turned OFF during the forced compressor operation in heating mode, the louver position (with the
auto swing) is returned to the level position.
Note (1) The compressor stops when it has entered the protective control.

– 5–
(11) Drain motor (DM) control [Applicable type: FDT, FDTC, FDTW, FDTS, FDTQ, FDUM, FDQS and FDU90～140]
(a) Drain motor (DM) start operation at the same time when compressor ON at cooling and dehumidifying mode and
keeps operating for 5 minutes after operation stop, the anomalous stop, thermostat OFF and switching from cooling or
dehumidifying operation to fan or heating operation.
Stop (1)
Indoor unit operation mode
Control A
Control B
Compressor ON
Compressor OFF
Cooling Dehumidifying HeatingFan(2) Note (1) Including the stop from cooling, dehumidifying,
fan and heating operation and the anomalous stop.
(2) Including the “Fan” operation according to the
mismatch of operation modes.
(i) Control A
1) Iftheoatswitchdetectsanyanomalousdrainingcondition,theunitstopswiththeanomalousstop(displaysE9)
and the drain pump starts.
2) Thedrainmotorkeepsoperatingwhiletheoatswitchisdetectingtheanomalouscondition.
(ii) Control B
 Iftheoatswitchdetectsanyanomalousdraincondition,thedrainmotoristurnedONfor5minutes,andat10seconds
afterthedrainmotorOFFitcheckstheoatswitch.Ifitisnormal,theunitisstoppedunderthenormalconditionor,if
thereis any anomalouscondition,E9isdisplayedand thedrainmotoristurnedON.(The ONconditionismaintained
during the drain detection.)
(b) Drain motor (DM) interlock control
(i) Start conditions
Depending on the function setting of the remote controller, the drain motor is turned ON under either one of the
following conditions.
1) During heating operation (Both the thermostat ON/OFF)
2) During heating operation (Both the thermostat ON/OFF) + Fan operation
3) Fan operation
(ii) Stop conditions
The drain motor is turned OFF 5 minutes after the stop of operations 1) to 3) above.
(12) Operation check/drain pump test run operation mode
(a) If the power is turned on when the dip switch (SW7-1) on the indoor PCB is ON state, it enters the mode of operation
check/drain pump test run. It is ineffective (prohibited) to change the switch after turning power on.
(b) Whenthecommunicationwiththeremotecontrollerhasbeenestablishedwithin60secondsafterturningpoweronbythe
dip switch (SW7-1) ON, it enters the operation check mode. Unless the remote controller communication is established, it
enters the drain pump test run mode.
Note (1) To select the drain pump test run mode, disconnect the remote control connector (CNB) on the indoor PCB to shut down the remote controller
communication.
(c) Operation check mode
There is no communication with the outdoor unit but it allows performing operation in respective modes by operating the
remote controller.
(d) Drain pump test run mode
When the drain pump test run is established, only the drain pump operates, and during operation the protective functions
by the microcomputer of indoor unit become ineffective.
(13) Indoor heat exchanger anti-frost (anti-frost control)
Thermostat OFF control
1) Thermostat is turned OFF depending on the temperature detected with the heat exchanger sensor (ThI-R1, R2)
during “Cooling” and “Dehumidifying” operations.
1.0
Forced thermostat OFF
Thermostat ON OK
Heat exchanger temperature
5-min timer Temperature drop
Temperature rising
10°C
2) For 4 minutes after the thermostat ON, the forced thermostat OFF control for the anti-frost protection is not effective.
a) When temperatures detected by the heat exchanger sensors ThI-R1 and R2 are higher than the anti-frost protection
temperature at 4 minutes after the thermostat ON, the detection starts from the state of thermostat ON.
3) If the temperature detected with the heat exchanger sensor ThI-R1 or R2 has stayed below the anti-frost protection
temperature(-0.5°C)continuouslyfor5minutesafter4minutesofthethermostatONoperation,thenthethermostatis
turned OFF forcibly.
The thermostat will be turned ON if temperatures detected by ThI-Ra and R2 picked up in the thermostat ON range.
4) “Anti-frost” signal is sent to the outdoor unit.

– 6–
(14) Anomalous fan motor (FDT and FDK only)
Fan motor will be stopped with displaying “E16”, if it has detected the revolutions of 200 rpm or less continuously for 30
seconds at a rate of 4 times within 60 minutes, after starting the motor.
(15) High ceiling control [Applicable type: FDT, FDTC, FDTW, FDTS and FDE]
When the indoor unit is installed at a high ceiling, the airow volume mode control can be changed with the indoor function of
wired remote controller “High ceiling setting”.
Setting Standard (Shipping) High Ceiling 1 High Ceiling 2
Remote controller setting Hi Me Lo Hi Me Lo Hi Me Lo
Fan speed Hi Me Lo UHi1
Hi Me UHi2 Hi Me
Note (1) It is set at Standard at the shipping from factory.
(2) At the hot start, heating thermostat OFF, or other, the indoor fan operate at the slow speed tap at each setting.
(16) Hot start
Indoor fan motor control is performed at the start of heating operation.
(a) When the temperature detected with the indoor heat exchanger thermistor (ThI-R1 or ThI-R2) drops 35°C or lower, it
control the fan with AC motor: Lo and DC motor: ULo.
(b) When the heat exchanger thermistor detects 45°C or higher with the fan running at Lo/ULo, it returns to the set airow
volume.
Set airflow volume
Lo/ULo
35°C 45°C
Heat exchanger thermistor temp. (ThI-R1 or R2)
(c) On the indoor unit of which the thermostat has been turned OFF during heating operation, the fan is turned OFF if the
heat exchanger thermistor temperature (Thi-R1 or Thi-R2) drops 25°C or lower.
(17) Detection room temperature compensation during heating
With the standard specication, the compressor is turned ON/OFF based on the setting temperature of thermostat. However,
when the thermostat OFF is likely to occur earlier because the unit is installed in a condition that warm air tends to accumulate
near the ceiling, the setting can be changed by using the indoor function of wired remote controller “Heating room temperature
compensation”. Since the compressor is turned ON/OF at one of the setting temperature at +3, +2 or +1°C, the feeling of
heating can be improved. However, the upper limit of setting temperature is 30°C.
Operation
Setting temperature
Room temp. (deg)
–1 +1
Stop
Standard
Compressor
Operation
Setting temperature Room temp. (deg)
+4+2
Stop
With setting at +3°C
Compressor
(18) Return air temperature compensation
This is the function to compensate a difference between the detected temperature of the Return air thermistor and the measured
temperature after installation of unit.
(a) It is adjustable in the unit of 0.5°C by using the indoor function of wired remote controller “Return air thermistor
compensation”.
• +1.0°C, +1.5°C and +2.0°C • −1.0°C, −1.5°C and −2.0°C
(b) Since the compensated temperature is transmitted to the remote controller and the outdoor unit, it is controlled with the
compensated temperature.
Note (1) Compensation of detection temperature is effective for the indoor unit sensor only.
(19) External control (Remote display)/Remote operation
Always connect the wired remote controller. Otherwise, you cannot perform the remote operation.
(a) Output for external control (remote display) (Optional remote RUN/STOP monitor kit can be utilized.)
Following output connectors (CNT) are provided on the indoor control PCB. Connect the remote RUN/STOP monitor kit
and pick up respective dry contact signal.
•Operation output: Outputs DC12V relay drive signal during operation.

– 7–
• Heating output: Outputs DC12V relay drive signal during heating operation.
• Compressor ON output: Outputs DC12V relay drive signal when the compressor is operating.
•Error output: When any anomalous condition occurs, it outputs DC12V relay drive signal.
(b) Remote operation input
Remote operation inputs (switch input, timer input) connectors (CnT) are provided on the indoor control PCB.
However, the remote operation by the CnT is not effective when “Center mode” is selected with the air-conditioner.
(i)
At the shipping from factory [Indoor function of wired remote controller “External input selector” is
set at the level input.]
• Startup at the input signal to CnT OFF  ON [Edge input] … Air-conditioner ON
• Stop at the input signal to CnT ON  OFF [Edge input] … Air-conditioner OFF
*ON
ONON OFF OFF
OFF
OFF
OFF OFF
ONON
ONON
OFF
OFF
*ON
CnT input
Air-conditioner A
Air-conditioner B
(ii) When the setting is changed to the pulse input at site using the indoor unit function of wired
remote controller “External input selector”
It becomes effective only when the input signal to CnT is changed OFF➝ON and the air-conditioner operation [ON/
OFF] is inverted.
ON
ON
OFF
OFF OFF
OFF
ON
OFF
OFF
ON
ON
CnT input
Air-conditioner A
Air-conditioner B
(c) Processing of emergency stop signal
This emergency stop signal is used to stop all indoor unis connected to the same outdoor unit in emergency.
1) The emergency stop control becomes effective if the emergency stop control setting is changed to “Valid” from the
wired controller.
2) If the emergency stop [E-63] signal is received from outdoor unit, it is transmitted to the remote controller and
makes stop.
(d) Fresh air processing operation input
1) If indoor unit controller receive fresh air processing operation signal (*1) or fresh air processing stop signal from
remote controller, it output ON signal or OFF signal from CnD connector respectively.
*1. Operation switch ON at interlock setting and ventilation switch ON at non-interlock setting.
2) Output relay is DC12V option and maximum relay load is LY2F (OMRON).
3)
In case of interlock setting, if either of indoor units connected to one remote controller is in the state of anomalous stop,
the fresh air processing unit connected to that indoor unit cannot be operated. Other processing units connected to the
indoor units operating normally can be operate.
In case of non-interlock setting, processing unit can start ventilation even though the connected indoor unit is in
anomalous stop.
4) In case of interlock setting if indoor unit stops, processing unit also stop.
5) In case of interlock setting if indoor unit stops with anomalous stop, processing unit also stop.
6) If indoor unit is started or stopped from center console, processing unit can start or stop in case of interlock setting,
but it keep stopping in case of non-interlock setting.
7) Interlock or non-interlock can be set only on the remote controller.
(20) Dip switch function
Model capacity selection with SW6 0 : OFF, 1 : ON
Model P22 P28 P36 P45 P56 P71 P80 P90 P112 P140 P160 P224 P280
SW6-10100001010101
SW6-20010100110011
SW6-30001100001111
SW6-40000011111111
Note (1) ON marked with * means ON by a remote
controller switch or other.

– 8–
1.3 Operation control function by the remote controller
(1) Switching sequence of the operation mode switches of remote controller
Dehumidifying Cooling Fan Heating
(2) [CPU reset]
When the “CHECK” and “GRILL” buttons on the remote controller are pressed at the same time, this function is activated.
This function is same as power supply reset.
(3) [Power failure compensation function]
• This function becomes effective when “POWER FAILURE COMPENSATION SET” is valid by setting the remote controller
functions.
• The remote controller's status is always stored in memory, and after recovery of power, operation is resumed according to
the memory contents. However the auto swing stop position and timer mode are cancelled, but the weekly timer setting is
restored with the holiday setting through all weekdays.
By resetting the clock and cancelling the holiday setting for each weekday after recovery of power, weekly timer setting
becomes effective.
• Contents stored in memory for power failure compenstion are as follows.
Note (1) Item ➅➆ and ➇ are stored in memory regardless of whether the power failure compensation setting is valid or invalid, and silent mode setting is
cancelled regardless of whether the power failure compensation setting is valid or invalid.
➀ Running or Stopping status just before power failure
If it had been operating under OFF timer mode or simple timer mode, memorzed status is as stopping (At the
recovery of power, the timer mode is cancelled but weekly timer setting is changed to the holiday setting through all
weekdays
➁ Operation mode
➂ Fan speed mode
➃ Room temperature setting
➄ Louver auto swing/stop
However, the stop position (position 4) is cancelled and is becomes the level position (position 1).
➅ “Remote control function items”, set with the remote controller function setting (“Indoor unit function items” are
stored in the inoor unit's memory.)
➆ Upper limit value and lower limit value set by temperature setting control.
➇ Clock timer setting and weekly timer setting (Other timer settings are not sotred in memory).
[Parts layout on remote controller PCB]
X Y
SW2
SW1
A
B
M
S
親
子
SW1
SW2
 Control selector switch (SW1)
Switch Function
SW1 MMaster remote controller
SSlave remote controller
Note (1) SW2 is not normally used, so do not change the selection.

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9
-
1.4 Operation control function by the outdoor controller
(A) Normal control
(1) Operation of major functional components under each operation mode
Functional
Components
Indoor unit fan
Compressor [CM1]
Compressor [CM2]
Outdoor unit fan [FMo-1]
Outdoor unit fan [FMo-2]
4 way valve [20S]
Solenoid valve [SV6] [SV7]
Solenoid valve [SV13]
Electronic expansion valve
for heating [EEVH1, 2]
Electronic expansion valve
for sub-cooling [EEVSC]
Indoor unit electronic
expansion valve
Operation
mode Cooling Heating
Defrost
Thermostat OFFThermostat ONThermostat OFFThermostat ON
Fan Dehumidify
Remote controller
command
Overheating
control response
Outlet temperature
control response
Overheating
Control Response
Fully open Fully closed
Slight opening
control
Model-specific
aperture opening
angle
Fully open ※1
※3Fully open ※3※4
Fully closed
※2
Fully closed Fully closed Fully closed Fully closed
※2
Overheating
control response
Opening angle
control
Fully closed
/ Fully open
Opening angle
control
Remote controller
command Remote controller command Remote controller command
Intermittent
operation → / 
/ 
/ 
/ 

→ 
→ 
→ 


/ 
/ / 
/
/




/ 

/ 
Inverter cooling fan
[FMC1, 2] / / / / / / 
/ 
/ 




/ 
/ 


/ 

/ 

Crankcase heater [CH1,2] / / / / / / / 




Magnetic contactor CM1
[52X1] /
Magnetic contactor CM2
[52X2] 
Solenoid valve [SV1] /    /   / / 
Solenoid valve [SV2] /    /   / / 
Notes(1) : ON, : OFF, /, /: ON or OFF
(2) ※1: The EEVH1, 2 of master unit are fully opened and those of slave unit are fully closed.
(3) ※2: When the unit is stopped from cooling operation, the EEVH1, 2 of master unit are fully opened and those of slave unit are fully closed.
When the unit is stopped from heating operation, the EEVH1, 2 of both master and slave units are fully closed unless the opening degree is specified
by the low pressure protective control.
(4) ※3: When the operation mode is changed from heating to cooling/dehumidifying, EEVH1, 2 are maintained at fully closed position and EEV of only one
indoor unit keeps 60 pulse until 20S is turned OFF.
(5) ※4: When the operation mode is changed from cooling/dehumidifying to heating, EEVH1, 2 are maintained at fully opened position and EEVs of all
indoor units keep 0 pulse until 20S is turned ON.
(6) This shows the state of output when all indoor units are in the same operation mode.

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10
-
(2) Compressor control (Master unit/slave unit)
(a) Starting compressor
(i) Compressor starting order (2 compressors specification)
After turning the power on, rstly CM1 compressor starts. (In case of the combination use, it is CM01 of master
unit) And corresponding to the condition of under-dome temperature and to the required capacity of indoor units
thermostat ON, the next compressor will start sequentially, and nally maximum 4 compressors ( in case of combi-
nation use) will start simultaneously.
1) Single use
The range of frequency for each compressor corresponding to the heat load is shown in below mentioned table.
(The table shows the case that CM1 starts rst. If CM2 starts rst, the frequency of CM2 should be applied that
of CM1 shown in heat load zone 1 instead.)
Following tabel is shown the case that the maximum compressor frequency is 120Hz.
Note (1) Value in ( ) are for the models FDC615, 680KXE6
2) Combination use
The range of frequency for each compressor corresponding to the heat load is shown in below mentioned
table. (The table shows the case that CM01 starts rst. If CM11 starts rst, the frequency of CM11 should be
applied that of CM01 shown in heat load zone 1 instead.)
Note (1) Value in ( ) are for the models FDC1180~1360KXE6
(ii) Rotation of compressor start/stop order
1) The compressors will be changed over by determinating the start/stop order in each heat load zone.
2) In case of single use, the starting order of CM1 and CM2 will be changed over on each occasion when the out-
door unit stops.
3) In case of combination use, the starting order of CM01(CM11) and CM02(CM12) will be changed over on each
occation when the master unit or slave unit stops all independently.
4) In case of combination use, the starting order of master and slave units will be changed over on each occasion
when the master unit or slave unit stops all independently.
Starting order of outdoor units Master→Slave→Master
(Reference)
Change in number of compressors operating
Note (1) Value in ( ) are for the models FDC615, 680KXE6 and FDC1180~1360KXE6
(2) After recovery of power blackout, starting order of compressor is always CM01of master unit.
Model
FDC335
~ 680
FDC735~1360
Starting Order of Outdoor Units Starting Order of Compressors
CM 1 →CM 2 →CM 1
Master →Slave →Master CM 1 →CM 2 →CM 1
−
CM1
Heat load zone
CM2
0
0Hz
0Hz
1
20~112Hz (22~92Hz)
0Hz
2
42 (34)~120Hz
42 (34)~120Hz
Heat load zone
Master unit
Slave unit
CM01
CM02
CM11
CM12
0
0Hz
0Hz
0Hz
0Hz
1
20~112Hz (20~92Hz)
0Hz
0Hz
0Hz
2
42~112Hz (34~92Hz)
0Hz
42~112Hz (34~92Hz)
0Hz
3
42~120Hz (34~120Hz)
42~120Hz (34~120Hz)
42~120Hz (34~120Hz)
42~120Hz (34~120Hz)
1-Compressor
2-compressors
4-compressors
80Hz
(60Hz) 112Hz (92Hz)
80Hz ×2
(66Hz ×2) 112Hz ×2
(92Hz ×2)

-
11
-
(3) Starting control of the compressor (Master unit/Slave unit)
According to the elapsed time after power ON and to the number of start-up, the starting control method of compressor is
shown in following table. However during the defrost control, oil return control and oil equalization control, the starting control
method of compressor is depended on that of the each control.
(a) 4-way valve switching safeguard (Master unit/Slave unit)
At starting, the inverter compressor (CM1, CM2) is operated under following conditions regardless of the decision frequency.
(i) 0-20Hz operation
It is operated in the range of 0-20Hz. However during this operation, the compressor protective controls like current safe
control, high pressure control, discharge pipe temperature control, low pressure control, power transistor temperature control,
under-dome temperature control and compression ratio protective control are not performed.
(ii) 25-40(48)Hz opearation
The maximum frequency is determined by the temperature detected with the outdoor air temperature thermistor (Tho-A).
1) In case of 0°C or lower of Tho-A: It starts to increase the frequency up to 48Hz as maximum frequency and
when the frequency reaches 48Hz, it stops.
2) In case of higher than 0°C of Tho-A: It starts to increase the frequency up to 40Hz as maximum frequency and.
when the frequency reaches 40Hz, it stops. However during this operation, if the starting conditions of the com-
pressor protective controls like current safe control, high pressure control, discharge pipe temperature control,
low pressure control, power transistor temperature control, under-dome temperature control or compression ratio
protective control is satised, this control ends and it is controlled according to such protective control satised
with. And if the compressor frequency is determined and this protective control is cancelled, it returns to the nor-
mal operation.
(b) Compressor protective start control (Master unit/Slave unit)
The compressor frequency is controlled regardless of the target frequency.
1) Up to 1minutes 45 seconds after the compressor starts, it is operated at 20Hz.
2) When 1minutes 45 seconds has elapsed after the compressor starts, it is operated at the frequency by compressor
potective start control.
(c) Compressor protective start control "A" according to the crankcase heater ON time (Master unit/Slave
unit)
If it is the 1st startup after 45 minutes of the cumulative crankcase heater ON time has elapsed since power ON or if it is
the subsequent startup after the compressor has stopped for 45 minutes or more since power ON, it starts operation accord-
ing to this control.
1) After 4-way valve switching safeguard, inverter frequency is set at 20Hz. And during reducing frequency to 20Hz
after 4-way valve switching safeguard, if the time for reaching to 20Hz is elasped 1 minutes after startup, it is set at
the maximum frequency after 1 minute elasped (20Hz+5Hz).
2) During the period of 15 minutes after the inverter frequency reaches to 10Hz (the frequency to complete startup), the
maximum inverter frequency will be increased from 20Hz by 5Hz per minute.
3) If the compressor stops within the period of 15 minutes after startup, and when the compressor starts again, the maxi-
mum inverter frequency is increased from 20Hz by 5Hz per minute during the cumlative period of 15 minutes under
this control after the initial startup.
Conditions Starting method
①The 1st startup after 45minutes or more has elapsed since
power ON, or the subsequent startup after the
compressor has been stopping for 45 minutes or longer
with keeping the power ON.
After 4-way valve switching safeguard, "compressor
protective start controlA" will be perfomed according to the
crankcase heater ON time. (See followings)
②The 1st startup after less than 45 minutes has elasped
since power ON After 4-way valve switching safeguard, "compressor
protective start control B" will be perfomed according to the
crankcase heater ON time. (See next page)
③The startup other than ①and ②mentioned above. After 4-way valve switching safeguard, "compressor
protective start controls" will be perfomed.

-
12
-
4) When the under-dome temperature (detected by Tho-C) exceeds 20°C and the under-dome superheat is 15degC, the
compressor protective start control "A" is cancelled and the inverter frequency will be increased by 5Hz per 25 seconds.
(d) Compressor protective start control "B" according to the crankcase heater ON time (Master unit/Slave
unit)
If it is the 1st startup after the cumulative crankcase heater ON time has elapsed less than 45 minutes since power ON
1) After 4-way valve switching safeguard, inverter frequency is set at 20Hz. And during reducing frequency to 20Hz
after 4-way valve switching safeguard, if the time for reaching to 20Hz is elasped 1 minutes after startup, it is set at
the maximum frequency after 1 minute elasped (20Hz).
2) During the period of 18 minutes after the inverter frequency reaches to 10Hz (the frequency to complete startup op-
eration), the maximum inverter frequency will be increased from 20Hz by 5Hz per 2 minute.
3) From 18 minutes to 24 minutes after startup, the maximum inverter frequency will be increased by 5Hz per 1 minute,
and this control will end when 24 minutes is elapsed after startup.
4) After this control ends once, if it is the 2nd startup or the period of 45 minutes after th power ON is elapsed, this con-
trol will be shifted to the compressor protective start control "A".
5) If the compressor stops within 24 minutes after startup, and when the compressor starts again, the compressor protective
start control "B" is performed during the cumlative period of 24 minutes after the initial startup. However when the period
of 45 minutes has elapsed since compressor stopped, the control is shifted to the compressor protective start control "A".
6) When the under-dome temperature (detected by Tho-C) exceeds 20°C and the under-dome superheat is 15degC, the
compressor protective start control "B" is cancelled and the inverter frequency will be increased by 5Hz per 25 sec-
onds.
(4) Solenoid valve (SV6,7) control for oil return from oil separator (Maste unit/Slave unit)
(a) When the compressor starts, the following solenoid valve for corresponding compressor is opened respectively.
(b) SV6, SV7 is kept open for the period of 3 minutes after 4-way valve switching safeguard control and compressor protective
control start.
(c) If the compressor frequency is 80Hz (68Hz) or higher, SV6,7 opens, and if the compressor frequency is 76Hz(64Hz) or
lower, it closes.
Note (1) Value in ( ) are for the models FDC615, 680KXE6 and FDC1180~1360KXE6
(d) If the compressor stops after SV6, 7 opens, SV6, 7 remains open for 3 minutes and 10 seconds, then closes.
76Hz
(64Hz) 80Hz (68Hz)
Actual compressor frequency (Hz)
SV6, 7 open
SV6, 7 closed
Run
command
OFF
Stop
3 minutes
15 sec.
OFF
Stop
76Hz or
lower
80Hz or higher
3 minutes
10 seconds
Solenoid valve
(SV6, 7)
Compressor
ON
20Hz
Compressor
Starts
Compressor
CM1
CM2
Solenoid valve
SV6
SV7

-
13
-
(5) Outdoor fan control (Master unit/slave unit)
(a) DC fan motor control
The outdoor fan is controlled from 0th speed to 4th speed, and set the standard speed according to the model and operation
mode.
Under normal condition, 1st speed and 4th speed is standard, and under each condition the stepless fan control between 1st
speed and 4th speed is performed.
(b) Outdoor fan speed and fan motor rotation speed
(c) At the unit startup, outdoor fan is operated at 4th speed.
(d) DC fan motor startup control
① When the outdoor fan starts after stopping, the startup fan control is performed by checking the fan speed.
② If the rotating direction of the stopping fan, either FMo1 or FMo2, is reverse and its speed is 700min-1 or higher, the
both fans cannot be started.
③ If the rotating direction of the stopping fans, both FMo1 and FMo2, are reverse but its speed is less than 700min-1 for
3 seconds continuously, the fan can be started.
④ During the period of 5 seconds after 52C1 is turned ON, the outdoor DC fan is prohibited to start.
Fan tap FDC335, 400
Cooling
FM
O 1
0th speed
1st speed
2nd speed
3rd speed
4th speed
0
0
0
160
960
FM
O 2
0
160
400
160
960
FM
O 1
0
0
0
160
960
FM
O 2
0
160
400
160
960
Heating FDC450 Cooling
FM
O 1
0
0
0
160
1080
FM
O 2
0
160
400
160
1080
FM
O 1
0
0
0
160
1080
FM
O 2
0
160
400
160
1080
Stop
1-unit operation min. speed
1-unit operation max. speed
2-unit operation min. speed
2-unit operation max. speed
Heating Remarks
Unit: min
-1
Fan tap
0th speed
1st speed
2nd speed
3rd speed
4th speed
FDC504〜680
Cooling
FMO1
0
0
0
160
1140
FMO2
0
160
400
160
1140
FMO1
0
0
0
160
1140
FMO2
0
160
400
160
1140
Stop
1-unit operation min. speed
1-unit operation max. speed
2-unit operation min. speed
2-unit operation max. speed
Heating Remarks
Unit: min-1

-
14
-
(6) Compressor pre-start control (Master unit/slave unit)
(a) The following control is performed when the compressor ON conditions are established.
(i) Pre-start control when the operation mode is same as previous operation mode:
1) In case of "Cooling /Dehumidifying" mode, 4-way valve is turned OFF. In case of "Heating" mode, 4-way valve
is turned ON.
However if the operation mode is same as previous operation mode and 4-way valve is retaing prescribed condi-
tion, the control status of 4-way valve is unchanged.
2) Solenoide valve SV6 and SV7 are turned ON.
3) The opening degree of EEVH1, 2 for heating and EEVSC for subcooling coil are set to the initial opening degree
mentioned in following table. The expansion valves EEVH1, 2 are operated rst, and after those operations are
completed, the expansion valve EEVSC will be operated.
Note (1) Expansion valves of master unit and slave unit are operated respectively.
4) Fan motors FMo1, FMo2 and compressor start 15 seconds after the compressor ON conditions are satised.
Cooling Heating
Heating
Cooling
FM
O 1,2
OFF
OFF
ON
ON
ON
20S
SV6
EEVH1,2 470
EEVSC
CM1 ON
CM2 ON
3 minutes
3 minutes
Open/close control
Opening degree control
Initial opening degree
Full-close or 100
pulse
Opening degree control
Full-close
OFF
OFF
Min. of 3 minutes 15 seconds 6 seconds
Compressor stop Compressor start
Starting conditions are satisfied
Operation mode
Cooling
EEVH1, 2
EEVSC
Name
Item
470
32 10 0
(Unit: Pulse)
Heating

-
15
-
(7) Crankcase heater control (Master unit/Slave unit)
(a) Crankcase heater ON (power on) and OFF (power off) are controlled with the under-dome temperature thermistor.
(b) Crankcase heater CH1 is turned ON, when the under-dome temperture (Tho-C1) <
= (SST)+20°C
(c) Crankcase heater CH1 is turned OFF, when the under-dome temperture (Tho-C1) <
= (SST)+25°C
(d) Crankcase heater CH2 is turned ON, when the under-dome temperture (Tho-C2) <
= (SST)+20°C
(e) Crankcase heater CH2 is turned OFF, when the under-dome temperture (Tho-C2) <
= (SST)+25°C
(Note) SST: Low pressure saturated temperature detected with low pressure sensor (LPS)
(f) Crankcase heater CH1 is turned OFF, when the under-dome temperature (Tho-C1) <
=－40°C and CM1 is ON
(g) Crankcase heater CH2 is turned OFF, when the under-dome temperature (Tho-C2) <
=－40°C and CM2 is ON
(Note) (f) and (g) are the protection for thermistor (Tho-C1, -C2) breakage
Heating Cooling
Cooling
Heating
FMo1,2
OFF
OFF
ON
20S
SV6
EEVH1,2
EEVSC
CM1
CM2
ON
ON
ON
3 minutes 3 minutes
Open/close control
Initial opening degree
Full-close
Opening
degree control
Opening
degree control Full-open
OFF
OFF
15 sec. 1 minute 45 secondsMin. of 3 minutes
Compressor stop Compressor start
Starting conditions are satisfied

-
16
-
(8) Defrrosting (Master unit/Slave unit)
If the defrost starting conditions at the outdoor heat exchanger are established, defrost operation starts.
(a) Temperature conditions for defrosting
(i) Conditions for starting defrost
When all of following conditions are satised, defrost operation will be started.
1) When the cumulative operation time
of the compressor becomes 33 minutes
after completion of previous defrost
operation, or it becomes 33 minutes after
heating operation starts.
2) When 8 minutes have elapsed after one
compressor is turned ON from the state
of all compressors OFF.
3) When 8 minutes have elapsed after one
outdoor fan is turned ON from the state
of all outdoor fan OFF.
4) After all of the above conditions are satised, and
when the temperatures detected with the outdoor heat exchanger temperature thermistor (Tho-R1,-R2) and
outdoor air temperature thermistor (Tho-A) are below the defrost starting temperature mentioned in the above
graph continuously for 3 minutes.
(ii) Conditions for finishing defrost
• Standard (J14 is shorted)
1) When the temperature detected with both outdoor heat exchanger temperature thermistors (Tho-R1 and
Tho-R2) is higher than 9ºC
2) Or when 12 minutes have elapsed since defrosting started.
• Cold region setting (J14 is open)
1) When (Tho-R1 and Tho-R2) >
= 9ºC is satised, after 2 minutes and 30 seconds have elapsed since defrosting
started, and when either of following conditions is satised, the defrosting end operation starts.
a) 2 minutes and 30 seconds have elapsed since the temperature of either Tho-R1 or Tho-R2 was 14ºC or
higher
b) The temperature of either Tho-R1 or Tho-R2 is 30ºC or higher.
c) 14 minutes have elapsed since defrosting started.
2) When (Tho-R1and Tho-R2) < 9ºC is satised, after 2 minutes and 30 seconds have elapsed since defrosting
started, and when either of following conditions is satised, the defrosting end operation starts.
a) 5 minutes have elapsed since the temperature of either Tho-R1 or Tho-R2 was 14ºC or higher.
b) The temperature of either Tho-R1 or Tho-R2 is 30ºC or higher.
c) 14 minutes have elapsed since defrosting started.
-20 -15 6
Without J15
Cold region
specification
With J15
Outdoor air temp. (ºC) [Tho-A]
Cold region
Defrost start zone
Standard
(Factory setting)
Heat exchanger temp. (°C) [Tho-R]
Fig.1
-2
-6
-15
-19
-21
-25

-
17
-
(9) Protective control
(a) Discharge pipe temperature control (Master unit/slave unit)
(i) If the discharge pipe temperature (detected with Tho-D1, D2) exceeds the set value, it makes the compressor capacity
control performed and the solenoid valves SV1, 2 (for cooling down the compressor) open according to the compressor
Hz in order to suppress the discharge pipe temperature rising.
1) Compressor capacity control
2) Solenoid valve (SV1, 2) control for cooling down compressor.
< ON conditions >
①In the zone A: SV1 is turned ON when Td1 >
=115°C. SV2 is turned ON when Td2 > =115°C.
②In the zone B: SV1 is turned ON when Td1 >
=110°C. SV2 is turned ON when Td2 > =110°C.
< OFF conditions>
①In the zone A: SV1 is turned OFF when Td1 <
=108°C. SV2 is turned OFF when Td2 > =108°C.
②In the zone B: SV1 is turned OFF when Td1 <
=103°C. SV2 is turned OFF when Td2 < =103°C.
(ii) Discharge pipe temperature control and Error display
1) When the discharger temperature exceeds 130°C or higher for 2 seconds continuously, it makes the compressor
stopped. And when the discharge pipe temperature decreases to lower than 90°C, it makes the compressor restarted
automatcally.
2) If this control [mentioned in (ii)-1)] is activates 5 times within 60 minutes, it makes the compressor anomalous
stop and displays E36, In case of anomalous stop, it cannot be operated again until the discharge pipe temperature
decreases to lower than 90°C for 60 minutes continuously.
(b) Current safe control
• Current safe control is done by both Master and Slave unit individually.
< Compressor capacity control >
1) Compressor frequency is controlled by detecting the inverter primary current (T-phase) and the inverter secondary
current.
However under the following operating status ①and ②, it does not detect the inverter current.
①Actual compressor frequency N < 20Hz
②During the period that actual compressor frequency is decreasing or during the period of 1 second after the actual
compressor frequency decreased.
110 120
Discharge pipe temperature (°C) [Tho-D1, D2]
Retention
Compressor capacity is
reduced at 5-second intervals
Reset
40HZ
(33HZ) 45HZ (38HZ)
• zone A • zone B
zoneA
zone B
108 115
Discharge pipe temperature (°C) [Tho-D1, D2]
ON ON
SV1 : OFF
SV2 : OFF SV1 : OFF SV2 : OFF103 110
Discharge pipe temperature (°C) [Tho-D1, D2]
Note (1) Value in ( ) are for the models FDC615, 680KXE6 and
FDC1180~1360KXE6

-
18
-
2) Initiation condition: When the detected current becomes following value.
① Within 2 minutes after starting operation of CM1 and CM2, the capacity control is done at the current safe value
for starting mentioned in a) and b)
② During capacity measurement mode, the capacity control is done at the current safe value for measurement mode
mentioned in a) and b)
a) The inverter primary current (Current safe 1): See following graph
(At starting and at measuring mode, the current safe value is the value (23.5A) at 35ºC of outdoor air tem-
perature)
b) The inverter secondary current (Current safe 2): 24A
(At starting and at measuring mode, the current safe values are same.)
* Both current safe values mentioned in a) and b) can be corrected by the code P21 of 7-segment input.
Correction value α = 3 to + 6 (0.5 interval)
Factory setting α = 0
3) Control contents
① The frequency of all compressors currently operating in the same refrigeration system will be decreased at every
one second by 2-steps (Current safe 1: rst step, Current safe 2: second step). The compressor that receives cur-
rent safe control command rst decreases the frequency and when its frequency is retaining at certain frequency,
such retained frequency information is transmitted to master unit.
② Master unit will send the command to all other operating compressors in same refrigeration system to decrease
frequency up to the same frequency as the rst compressor reduced to according to the information of the rst
compressor.
③ After the frequency is decreased, if the inverter current within the detection range is still above the current safe
value, the procedure ① will be repeated.
④ After the frequency is decreased, if the inverter current within the detection range is lower than the current safe
value, compressors will keep that frequency.
⑤ The minimum indicated frequency Ni by this control is 20Hz.
Example 1: In case of heat load zone 3 mentioned in Page 2, the operation of 20Hz×4 compressors is minimum (not
42Hz×4 mentioned in the table).
Example 2 : In case of heat load zone 2 mentioned in Page 2, the operation of 20Hz×2 compressors is minimum (not
42Hz×2 mentioned in the table).
Outdoor air temperature (°C)
Inverter current (A)
30
25
20
15
10
23.5
35 39 43 47 50
22.3 19.7
11.2
11.2
16.2