Mitsubishi Heavy Industries FDTC25VH1 User manual

SM-
SERVICE MANUAL
SRR25ZS-W
SRR35ZS-W
FDTC25VH1
FDTC35VH1
(Split system, air to air heat pump type)
INVERTER RESIDENTIAL
AIR-CONDITIONERS
Ceiling concealed type
4-way ceiling cassette type
285

'20 • SR-SM-285
-
1
-
1. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER ............... 3
1.1 Models SRR25ZS-W,35ZS-W .................................................................. 3
................................... 4
(1) Operation control function by wireless remote control
(4) Installing two air-conditioners in the same room
............................................................................. 4(3) Auto restart function
(2) Unit ON/OFF button .............................................................................. 4
.......................... 3
.............................................................................. 5(7) Economy operation
........................................................................... 5(6) High power operation
(5) Selection of the annual cooling function .............................................. 5
(8) Timer operation .................................................................................... 6
CONTENTS
(12) Outline of cooling operation ................................................................. 8
(11) Outline of heating operation ................................................................. 6
(13) Outline of dehumidifying (DRY) operation .............................................. 8
(14) Outline of automatic operation ............................................................ 9
(15) Protective control function ................................................................... 9
........................ 47
.................................................................................. 46
1.2 Models FDTC25VH1, 35VH1 .................................................................. 15
1.2.1 Remote control (option parts)............................................................... 15
1.2.3 Operation control function by the indoor control................................... 21
1.2.2 Operation control function by the wired remote control........................ 18
1.2.4 Operation control function by the outdoor control................................. 40
(4) Troubleshooting procedure (If the air-conditioner runs)
2.1 SRR series ................................................................................................ 46
(3) Troubleshooting procedure
(If the air-conditioner does not run at all) ........ 46
(1) Cautions ................................................................................................ 46
(2) Items to check before troubleshooting ................................................. 46
(10) How to make sure of wireless remote control ....................................... 64
.............................................................. 65
(12) Outdoor unit inspection points
(5) Self-diagnosis table .............................................................................. 48
(6) Service mode (Trouble mode access function) .................................... 49
(8)
Phenomenon observed after short-circuit, wire breakage on sensor .......... 62
(7) Inspection procedures corresponding to detail of trouble ..................... 57
(9) Checking the indoor electrical equipment ............................................. 62
2. MAINTENANCE DATA
(9) Silent mode .......................................................................................... 6
(10) Night setback ....................................................................................... 6
.
... 64
(11)
Inspection procedure for blown fuse on the indoor and outdoor unit PCB

'20 • SR-SM-285
-
2
-
(3) Troubleshooting at the indoor unit ........................................................ 70
(2) Troubleshooting procedure ................................................................... 70
(5) Check of anomalous operation data with the remote control ................ 74
(6) Inverter checker for diagnosis of inverter output .................................. 76
(7) Outdoor unit inspection points ............................................................... 77
.................................................................................... 80(2) Troubleshooting
...................................................................................... 79(1) List of troubles
2.2.2 Troubleshooting flow
(4) Troubleshooting at the outdoor unit ...................................................... 73
.......................................................................... 79
3. ELECTRICAL WIRING .................................................................................122
4. PIPING SYSTEM ..........................................................................................125
.............................................................................................. 67
2.2 FDTC series
2.2.1 Diagnosing of microcomputer circuit ............................................... 67
(1) Selfdiagnosis function ........................................................................... 67

'20 • SR-SM-285
-
3
-
1. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER
1.1 Models SRR25ZS-W, 35ZS-W
(1) Operation control function by wireless remote control
ONOCEREMITNUR
ON
/ OFF
HI POWER
Unit display section
ECONO light (orange)
Illuminates during ECONOMY operation.
HI POWER light (green)
Illuminates during HIGH POWER operation.
TIMER light (yellow)
Illuminates during TIMER operation.
This button can be used for turning on/off the unit when
remote control is not available.
Wireless remote control signal receiver
Unit ON/OFF button
RUN (HOT KEEP) light (green)
•Illuminates during operation.
•
Blinks when airflow stops due to the ‘HOT
KEEP’
and ‘ CLEAN operation ’.
ON
OFF
1.5 sec.
0.5 sec.
HOT KEEP
3 sec.
1 sec.
ON
OFF
CLEAN operation
ON
OFF
0.5 sec.
0.5 sec.
Operation mode
invalid
OPERATION MODE select button
ON/OFF (luminous) button
TEMPERATURE button
AIR FLOW (UP/DOWN) button
TIME SET UP switch
SLEEP button
CLEAN switch
ON TIMER button
TIMER button
ACL switch
PROGRAM button
Operation section
HI/ECO button
SILENT button
OFF TIMER button
WEEKLY button
FAN SPEED button
NIGHT SETBACK button
SET/Child Lock button
CANCEL button
Transmission section
Each time the button is pressed, the mode
changes.
•The above illustration shows all controls, but in
practice only the relevant parts are shown.
Press to start operation, press again to
stop.
This button sets the room temperature.
This button changes the air flow (up/down)
direction.
This switch is for setting the time.
This button selects SLEEP operation.
This switch selects the CLEAN
operation.
This button selects ON TIMER operation.
This buttions is used for setting the cur-
rent time and timer function.
Switch for resetting microcomputer.
This button sets WEEKLY TIMER.
This button changes the HIGH POWER/
ECONOMY operation.
This buttion changes the SILENT
operation.
This button selects OFF TIMER
operation.
This button switches the WEEKLY
TIMER to ON/OFF.
Each time the button is pressed, the fan
speed changes.
This button sets NIGHT SETBACK
operation.
Use this button to set the timer and
Child Lock.
This button cancels the ON timer, OFF
timer, and SLEEP operation.
Unit display sectionUnit display section
RUN (HOT KEEP) light (green)
・Illuminates during operation.
・
Blinks when airflow stops due to the ‘ HOT
KEEP
’ and ‘ CLEAN operation ’ .
ECONO light (orange)
Illuminates during ECONOMY operation.
TIMER light (yellow)
Illuminates during TIMER operation.
HI POWER light (green)
Illuminates during HIGH POWER operation.
Unit ON/OFF button
This button can be used for turning on/off the
unit when wireless remote control is not available.
Wireless remote control signal receiver
ON
OFF
1.5 sec.
0.5 sec.
HOT KEEP
3 sec.
1 sec.
ON
OFF
CLEAN operation
Operation mode
invalid
ON
OFF
0.5 sec.
0.5 sec.

'20 • SR-SM-285
-
4
-
(2) Unit ON/OFF button
When the wireless remote control batteries become weak, or if the wireless remote control is lost or malfunctioning, this but-
ton may be used to turn the unit on and off.
(a) Operation
Push the button once to place the unit in the automatic mode. Push it once more to turn the unit off.
(b) Details of operation
The unit will go into the automatic mode in which it automatically determines, from indoor temperature (as detected by sen-
sor), whether to go into COOL, DRY or HEAT modes.
(3) Auto restart function
(a)
Auto restart function records the operational status of the air-conditioner immediately prior to be switched off by a power
cut, and then automatically resumes operations after the power has been restored.
(b) The following settings will be cancelled:
(i) Timer settings
(ii) HIGH POWER operation
Notes (1) Auto restart function is set at on when the air-conditioner is shipped from the factory. Con-
sult with your dealer if this function needs to be switched off.
(2) When power failure ocurrs, the timer setting is cancelled. Once power is resumed, reset the
timer.
(3)
If the jumper wire (J170) “AUTO RESTART” is cut, auto restart is disabled. (See the diagram
at right.)
Jumper wire (J170)
RUN (HOT KEEP) light (green)
・Illuminates during operation.
・
Blinks when airflow stops due to the ‘ HOT
KEEP ’ and ‘ CLEAN operation ’ .
ECONO light (orange)
Illuminates during ECONOMY operation.
TIMER light (yellow)
Illuminates during TIMER operation.
HI POWER light (green)
Illuminates during HIGH POWER operation.
Unit ON/OFF button
This button can be used for turning on/off the
unit when remote control is not available.
Remote control signal receiver
ON
OFF
1.5 sec.
0.5 sec.
HOT KEEP
3 sec.
1 sec.
ON
OFF
CLEAN operation
Unit ON/OFF button
Function
Operation mode
Indoor temperature
setting
Fan speed Flap/Louver Timer switch
COOL About 24ºC
Auto Auto Continuous
DRY About 25ºC
HEAT About 26ºC
When two air-conditioners are installed in the room, use setting when the two air-conditioners are not operated with one wireless
remote control. Set the wireless remote control and indoor unit.
ࠉ
(a) Setting the wireless remote control
(i) Pull out the cover and take out batteries.
(ii) Disconnect the switching line next to the battery with wire cutters.
(iii) Insert batteries. Close the cover
.
ࠉ
(b) Setting an indoor unit
(i)
Turn off the power source, and turn it on after 1 minute.
(ii) Point the wireless remote control that was set according to the procedure described
on the left side at the indoor unit display section and send a signal by pressing the
ACL switch on the wireless remote control.
Since the signal is sent in about 6 seconds after the
ACL switch is pressed,
point the wireless remote control at the indoor unit display section for some time.
(iii) Check that the reception buzzer sound "Peep" is emitted from the indoor unit.
At completion of the setting, the indoor unit emits a buzzer sound "Peep".
(If no reception tone is emitted, start the setting from the beginning again.)
Disconnect
(4) Installing two air-conditioners in the same room
Reception
Peep

'20 • SR-SM-285
-
5
-
(a) The annual cooling control is valid from factory default setting. It is possible
to disable by cutting jumper wire (J172), or changing the setting of DIP switch
(SW2-4) on the interface kit (option) PCB if it is connected.
Note: (1) Default states of the jumper wire (J172) and the interface kit at the shipping from factory – On the
PCB, the DIP switch (SW2-4) is set to enable the annual cooling function.
(2) To cancel the annual cooling setting, consult your dealer.
(b) Content of control
(i) If the outdoor air temperature sensor (TH3) detects below 5°C, the indoor
unit speed is switched to 8th step.
(ii) If the outdoor air temperature sensor (TH3) detects higher than 17°C, the indoor unit speed is changed to the normal
control speed.
Jumper wire
(J172)
Interface kit
(SC-BIKN2-E)
SW2-4
Function
Shorted ON Enabled
Shorted OFF Disabled
Open ON Disabled
Open OFF Disabled Jumper wire (J172)
ON
5 17
OFF
Outdoor air temperature ( C)
Pressing the HI POWER/ECONO button intensifies the operating power and initiates powerful cooling and heating operation
for 15 minutes continuously. The wireless remote control displays and the FAN SPEED display disappears.
(a) During the HIGH POWER operation, the room temperature is not controlled. When it causes an excessive cooling and heating,
press the HI POWER/ECONO button again to cancel the HIGH POWER operation.
(b) HIGH POWER operation is not available during the DRY and the program timer operations.
(c) When HIGH POWER operation is set after ON TIMER operation, HIGH POWER operation will start from the set time.
(d) When the following operation are set, HIGH POWER operation will be canceled.
①When the HI POWER/ECONO button is pressed again.
④When the SILENT botton is pressed.
②When the operation mode is changed. ⑤When the NIGHT SETBACK botton is pressed.
③When it has been 15 minutes since HIGH POWER operation has started.
(e) Not operable while the air-conditioner is OFF.
(f) After HIGH POWER operation, the sound of refrigerant flowing may be heard.
(6) High power operation
Pressing the HI POWER/ECONO 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. The
wireless remote control displays ECONO mark and the FAN SPEED display disappears.
(a) It will go into ECONOMY operation at the next time the air-conditioner runs in the following cases.
①When the air-conditioner is stopped by ON/OFF button during ECONOMY operation.
②When the air-conditioner is stopped in SLEEP or OFF TIMER operation during ECONOMY operation.
③When the operation is retrieved from CLEAN operation.
(b) When the following operation are set, ECONOMY operation will be canceled.
①When the HI POWER/ECONO button is pressed again.
②When the operation mode is changed DRY to FAN.
③When the NIGHT SETBACK botton is pressed.
(c) Not operable while the air-conditioner is OFF.
(d) The setting temperature is adjusted according to the following table.
①at the start of operation
②one hour after the start of operation
③two hours after the start of operation
Temperature
adjustment
Cooling Heating
①＋0.5 ①−1.0
②＋1.0 ②−2.0
③＋1.5 ③−2.5
Mode
Item
(7) Economy operation
(5) Selection of the annual cooling function

'20 • SR-SM-285
-
6
-
(b) Sleep timer operation
Pressing the SLEEP button causes the temperature to be controlled with respect to the set temperature.
(8) Timer operation
(a) Comfortable timer setting (ON timer)
(c) OFF timer operation
The Off timer can be set at a specic time (in 10-minute units) within a 24-hour period.
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 indoor temperature at the setting time (temperature of room tempera-
ture sensor) and the setting temperature.
(9) Silent mode
As “Silent mode start” signal is received from the wireless remote control, it operates by dropping the outdoor fan tap and the
compressor command speed.
(10) Night setback
As “Night setback” signal is received from the wireless remote control, the heating operation starts with the setting temperature
at 10℃.
Outdoor fan tap
(Upper limit)
Compressor command
speed (Upper limit)
Cooling Heating Cooling Heating
SRR25ZS-W SRR35ZS-W
4th speed
37 rps
4th speed
46 rps
5th speed
46 rps
4th speed
56 rps
(11) Outline of heating operation
(d) Weekly timer operation
Timer operation (ON timer, OFF timer) can be set up to 4 times a day for each weekday.
ON OFF
ON ON
ON OFF
(few minutes ON)
ON ON(HOT KEEP)
OFF
OFF
(3 minutes ON)
OFF
OFF
Thermostat ON Thermostat OFF Failure
Heating
Compressor
Indoor fan motor
Outdoor fan motor
4-way valve
(b) Details of control at each operation mode (pattern)
(i) Fuzzy operation
Deviation between the indoor temperature setting correction temperature and the return air temperature is calcu-
lated in accordance with the fuzzy rule, and used for control of the air capacity and the compressor speed.
When the defrosting, protection device, etc. is actuated, operation is performed in the corresponding mode.
(ii) Hot keep operation
If the hot keep operation is selected during the heating operation, the indoor blower is controlled based on the
temperature of the indoor heat exchanger (Th2) to prevent blowing of cool wind.
However, if the fan speed setting is HI and room temperature is 19ºC or higher, this control is not executed.
30-115rps
30-115rps
30-62rps
30-46rps
SRR35ZS-W
30-102rps
30-102rps
30-58rps
30-76rps30-72rps
30-42rps
SRR25ZS-W
Model
Fan speed
Auto
MED
HI
ULO
LO
(a) Operation of major functional components in heating mode

'20 • SR-SM-285
-
7
-
5) During continuous compressor operation
In addition, when the speed command from the indoor control of the indoor unit during heating operation has counted
0 rps 10 times or more and all conditions of 1), 2) and 3) above and the outdoor air temperature is 3°C or less are satis-
ed (note that when the temperature for outdoor heat exchanger temperature sensor (TH2) is -5°C or less: 62 rps or
more, -4°C or less: less than 62 rps), defrost operation is started.
(ii) Ending conditions (Operation returns to the heating cycle when either one of the following is satised.)
1) Outdoor heat exchanger temperature sensor (TH2) : 13ºC or higher
2) Continued time of defrost operation → For more than 15 minutes
Max. 15 minutes
Heating operatio
n
¡Defrost operation
Depends on an operation condition, the time can be longer than 7 minutes.
2-7 minutes 
Hot keep operation
(c) Defrost operation
(i) Starting conditions (Defrost operation can be started only when all of the following conditions are satised.)
1) After start of heating operation
When it elapsed 35 minutes (Accumulated compressor operation time)
2) After end of defrost operation
When it elapsed 35 minutes (Accumulated compressor operation time)
3) Outdoor heat exchanger temperature sensor (TH2)
When the temperature has been below –5ºC for 3 minutes continuously
4) The difference between the outdoor air sensor temperature and the outdoor heat exchanger temperature sensor
¡The outdoor air temperature ≧0°C : 7°C or higher
¡-15°C ≦The outdoor air temperature ＜0°C : 3/15 × The outdoor air temperature + 7°C or higher (SRR25)
4/15 × The outdoor air temperature + 7°C or higher (SRR35)
¡The outdoor air temperature < -15°C : -5°C or higher
-20
-20 -15 -10 -5 0 5 10
-15
-10
-5
0
Outdoor air temperature (℃)
Outdoor heat exchanger temperature (
℃)
-20
-20 -15 -10 -5 0 5 10
-15
-10
-5
0
Outdoor air temperature (℃)
Outdoor heat exchanger temperature (℃)
Defrost operation
start
Defrost operation
start
Defrost operation start temperature
Defrost operation start temperature
Models 20～35 Model 50
-20
-20 -15 -10 -5 0 5 10
-15
-10
-5
0
Outdoor air temperature (℃)
Outdoor heat exchanger temperature (℃)
-20
-20 -15 -10 -5 0 5 10
-15
-10
-5
0
Outdoor air temperature (℃)
Outdoor heat exchanger temperature (℃)
Defrost operation
start
Defrost operation
start
Defrost operation start temperature
Defrost operation start temperature
Models 20～35 Model 50
SRR25 SRR35

'20 • SR-SM-285
-
8
-
(12) Outline of cooling operation
(b) Detail of control in each mode (Pattern)
(i) Fuzzy operation
During the fuzzy operation, the air ow and the compressor speed are controlled by calculating the difference be-
tween the indoor temperature setting correction temperature and the retum air temperature.
ON OFF OFF
OFF OFF OFF
ON OFF
(few minutes ON)
OFF
(few minutes ON)
ON ON OFF
Thermostat ON Thermostat OFF Failure
Cooling
Compressor
Indoor fan motor
Outdoor fan motor
4-way valve
20-96rps
20-96rps
20-74rps
20-58rps
SRR35ZS-W
20-74rps
20-74rps
20-55rps
20-45rps
SRR25ZS-W
Model
Fan speed
Auto
MED
HI
LO
20-44rps20-34rps
ULO
(13) Outline of dehumidifying (DRY) operationion
(a) Purpose of DRY mode
The purpose is "Dehumidication", 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.
(b) Outline of control
(i) Indoor unit fan speed and compressor are controlled by the area which is selected by the temperature difference.
(ii) The indoor unit check the current area by every 5 minutes, and operate by the next checking.
(c) Other
When the outside temperature and room temperature is low for cooling operation, indoor unit can not operate in cooling,
and dehumidify. In this case, the units operate in heating to rise the room temperature, and after that start DRY operation.
Indoor unit fan speed
Area
DCBA
Me speed
Indoor unit
fan speedULo(Lo) speed
STOP
Limited䠄Lower than
normal cooling operation䠅
Compressor
Limited
speed
Minimum 䠄Lower than the speed in ”Area A”䠅
STOP
Setting temperature
Difference between setting temperature and return temperature
(a) Operation of major functional components in cooling mode

'20 • SR-SM-285
-
9
-
(b) The unit checks the temperature every hour after the start of operation and, if the result of check is not same as the previous
operation mode, changes the operation mode.
(c) When the unit is started again within one hour after the stop of automatic operation or when the automatic operation is se-
lected during heating, cooling or dehumidifying operation, the unit is operated in the previous operation mode.
(d) Setting temperature can be adjusted within the following range. There is the relationship as shown below between the sig-
nals of the wireless remote control and the setting temperature.
(e) When the unit is operated automatically with the wired remote control connected, the cooling operation is controlled ac-
cording to the display temperatures while the setting temperature is compensated by +1°C during dehumidifying or by +2°C
during heating.
(14) Outline of automatic operation
(a) Determination of operation mode
The unit checks the indoor air temperature and the outdoor air temperature, determines the operation mode, and then be-
gins in the automatic operation.
27.5
25.5
19.5
18
A
30
Heating
Dehumidifying
Cooling
Indoor air temperature (˚C)
Outdoor air temperature (˚C)
(i)
(ii)
(iii)
When both the indoor and the outdoor air temperatures are in the range “A”, cooling or heating is switched depending on
the difference between the setting temperature and the indoor air temperature.
When the operation mode has been judged following the change of setting temperature with the remote control, the hourly
judgment of operation mode is cancelled.
If the setting temperature is changed with the wireless remote control, the operation mode is judged immediately.
Signals of wireless remote control (Display)
–6 –5 –4 –3 –2 –1 ±0 +1 +2 +3 +4 +5 +6
Setting
temperature
Cooling 18 19 20 21 22 23 24 25 26 27 28 29 30
Dehumidifying 19 20 21 22 23 24 25 26 27 28 29 30 31
Heating 20 21 22 23 24 25 26 27 28 29 30 31 32
Unit : ºC
(a) Frost prevention control (During cooling or dehumidifying)
(15) Protective control function
(17) Frost prevention control
( i ) Operating conditions
( ii ) Detail of anti-frost operation
(iii) Reset condition
Indoor heat exchanger
temperature (ºC)
2.
58
Operation mode
Item Protective control Reset
Compressor operation
Indoor fan
Forced outage Operation instruction
Depends on operation mode
8
2.51)
2)
Reset
Protective
control