Mitsubishi SRK25ZSP-W User manual

INVERTER WALL MOUNTED TYPE
RESIDENTIAL AIR-CONDITIONERS
(Split system, air to air heat pump type)
SRK25ZSP-W
SRK35ZSP-W
SRK45ZSP-W
Manual No.'18 • SRK-SM-259
SERVICE MANUAL

'18 • SRK-SM-259
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CONTENTS
1. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER ................... 2
(8) Timer operation ........................................................................................ 5
...................................... 3
(1) Operation control function by wireless remote control
(7) Air flow direction adjustment .................................................................... 4
(6) Economy operation .................................................................................. 4
(5) High power operation ............................................................................... 4
(4) Installing two air-conditioners in the same room
................................................................................. 3(3) Auto restart function
(2) Unit ON/OFF button ................................................................................. 3
............................. 2
(9) Outline of heating operation ..................................................................... 5
(11) Outline of automatic operation ................................................................. 7
(10) Outline of cooling operation ..................................................................... 7
(12) Protection control function ....................................................................... 8
......................... 17
................................................................................. 16
(4) Troubleshooting procedure (If the air-conditioner runs)
(3) Troubleshooting procedure
(If the air-conditioner does not run at all)
........ 16
(1) Cautions ................................................................................................. 16
(2) Items to check before troubleshooting ................................................... 16
(5) Self-diagnosis table ............................................................................... 18
(6) Service mode (Trouble mode access function) ..................................... 19
(7) Inspection procedures corresponding to detail of trouble ...................... 27
2. MAINTENANCE DATA
................................................................................. 37
(1) Indoor units ........................................................................................... 37
(2) Outdoor units ........................................................................................ 38
3. ELECTRICAL WIRING
.......................................................................................... 40
4. PIPING SYSTEM
(10) How to make sure of wireless remote control ........................................ 33
(11) Outdoor unit inspection points ............................................................... 34
(8)
Phenomenon observed after short-circuit, wire breakage on sensor .......... 31
(9) Checking the indoor electrical equipment .............................................. 32

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1. OUTLINE OF OPERATION CONTROL BY MICROCOMPUTER
(1) Operation control function by wireless remote control
◆Operation section
OPERATION MODE select button
Each time the button is pressed, the
mode changes.
•The above illustration shows all controls, but in
practice only the relevant parts are shown.
ON/OFF (luminous) button
Press to start operation, press again to
stop.
TEMPERATURE button
These buttons set the room temperature.
(These buttons are used for setting the
current time and timer function as well.)
CANCEL button
This button cancels the ON timer, OFF
timer, and SLEEP operation.
HI POWER/ECONO button
This button changes the HIGH POWER/
ECONOMY mode.
ON TIMER button
This button selects ON TIMER operation.
OFF TIMER button
This button selects OFF TIMER
operation.
SLEEP button
This button selects SLEEP operation.
CLEAN switch
This switch selects the SELF CLEAN
mode.
FAN SPEED button
Each time the button is pressed, the fan
speed changes.
AIR FLOW (UP/DOWN) button
This button changes the air flow
(up/down) direction.
ACL switch
This switch resets the program to default
state.
Unit display section
Remote control
This button can be used for turning on/off
the unit when a remote control is not available.
Unit ON/OFF button RUN light (green)
•Illuminates during operation.
•Blinks slowly when SELF CLEAN operation
(3 seconds ON, 1 second OFF).
•Blinks when air flow is stopped to
prevent blowing out of cold air in
heating operation. (1.5 seconds ON,
0.5 seconds OFF)
TIMER light (yellow)
Ⅰ ll uminates during TIMER operation.
Wireless remote control signal receiver

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(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.
(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 room temperature (as detected by
sensor), whether to go into the 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. Consult
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 (J1) “AUTO RESTART” is cut, auto restart is disabled. (See the diagram at right.)
(4) Installing two air-conditioners in the same room
When two air-conditioners are installed in the room, set the wireless
remote contrrol and indoor unit as belows to prevent operating air-condi-
tioners with one wireless remote control.
(a) Setting an indoor unit’s printed circuit board
(i) Take out the printed circuit board from the control box.
(ii) Disconnect jumper wire (J2) with wire cutters.
(iii) Install a printed circuit board.
(b) Setting a 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.
Jumper wire (J2)
Cut
Function
Operation mode
Room temperature
setting
Fan
speed Flap Timer
switch
COOL About 24ºC
Auto Auto
Continuous
DRY About 24ºC
HEAT About 26ºC
Jumper wire (J1)
Unit ON/OFF button

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(7) Air flow direction adjustment
Air ow direction can be adjusted with by AIR FLOW 
(UP/DOWN) button on the wireless remote control.
(a) Flap
Each time when you press the AIR FLOW 
(UP/DOWN) button the mode changes as follows.
COOL, DRY, FAN
Remote control
display
HEAT
Angle of flap from horizontal
Approx. 15°
Approx. 25°
Approx. 25°
Approx. 35°
Approx. 35°
Approx. 50°
Approx. 45°
Approx. 59°
Approx. 59°
Approx. 65°
(Swing)
(Flap stopped)
(5) High power operation
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 HIGH POWER mark 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 hea-
ting, 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 ON timer to OFF 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.
②When the operation mode is changed.
③When it has been 15 minutes since HIGH POWER operation has started.
(e) Not operable while the air-conditioner is OFF.
(6) Economy operation
Pressing the HI POWER/ECONO button initiates a soft operation with the power suppressed in order to avoid an excessive
cooling or heating. The unit operates 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.
Temperature
adjustment
Cooling Heating
①＋0.5 ①－1.0
②＋1.0 ②－2.0
③＋1.5 ③－2.5
Mode
Item
(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.
(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.

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(b) Swing
Flap moves in upward and downward directions continuously.
◆ In HEAT operation ◆ In COOL, DRY, FAN operation
Approx. 35°
Approx. 65°
Approx.
20°
Approx. 59°
(c) Memory flap
When you press the AIR FLOW (UP/DOWN) button once while the ap is operating, it stops swinging at the position.
Since this angle is memorized in the microcomputer, the ap will automatically be set at this angle when the next opera-
tion is started.
(d) When not operating
The ap returns to the position of air ow directly below, when operation has stopped.
(8) Timer operation
(a) 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 (temperature of
room temperature sensor) and the setting temperature.
(b) Sleep timer operation
Pressing the SLEEP button causes the temperature to be controlled with respect to the set temperature.
(c) OFF timer operation
The Off timer can be set at a specic time (in 10-minute units) within a 24-hour period.
(9) Outline of heating operation
(a) Operation of major functional components in heating mode
(b) Details of control at each operation mode (pattern)
(i) Fuzzy operation
Deviation between the room temperature setting correction temperature and the suction air temperature is calculated in
accordance with the fuzzy rule, and used for control of the air capacity and the compressor speed.
When the defrost operation, protection device, etc. is actuated, operation is performed in the corresponding mode.
ON OFF OFF
ON ON OFF
ON OFF
(few minutes ON) OFF
ON ON(HOT KEEP) OFF
OFF
OFF
(3 minutes ON)
OFF
OFF
Thermostat ON Thermostat OFF Defrost Failure
Heating
Compressor
Indoor fan motor
Outdoor fan motor
4-way valve
20
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115rps 20
-
100rps
20
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115rps 20
-
100rps
20
-
72rps 20
-
84rps 20
-
90rps
20
-
54rps 20
-
62rps 20
-
58rps
Model
Fan speed SRK25ZSP-W SRK35ZSP-W SRK45ZSP-W
AUTO
MED
HI
LO

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(ii) Hot keep operation
During the heating operation, the indoor fan speed can be controlled based on the temperature of the indoor heat ex-
changer (Th2) to prevent blowing of cold air.
-20
-25
-15
-10
-5
0
Outdoor heat exchanger temperature (
℃)
TH1
TH1
-20
-25
-20 -15 -10 -5 0 5 10
-15
-10
-5
0
Outdoor air temperature (℃)
-20 -15 -10 -5 0 5 10
Outdoor air temperature (℃)
TH2
TH2
Outdoor heat exchanger temperature (℃)
Defrost operation
start
Defrost operation
start
Defrost operation start temperature
Defrost operation start temperature
Models SRK25, 35, 45ZSP-W
Model DXK15Z6-S
(c) Defrost operation
(i)
1)
2)
3)
4)
－
(model SRK35 : 45)
35
35 (model SRK35 : 45)
•0℃≦TH2: TH2
－
TH1≧7℃, TH1≦TH2
－
7℃
•
－
15℃≦TH2＜0℃: TH2
－
TH1≧2/15×TH2＋7℃, TH1≦13/15×TH2
－
7℃
•TH2＜
－
15℃: TH2
－
TH1≧
－
5℃, TH1≦TH2＋5℃
satisfied.
is as
5)
1)
2)
－
－
(ii)
1) 2) 3) 5)
16 minutes and 50 seconds (model SRK45 : 17 minutes
and 30 seconds).
Total
Total
or less
follows.
(SRK45 : 10 )
(9)ࠉOutline of heating operation
(a) Operation of major functional components in heating mode
(b) Details of control at each operation mode (pattern)
1) Fuzzy operation
2) Hot keep operation
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
(c) Defrosting operation
(i)
1)
2)
3)
4)
−
≧
− ≦ ＜
30~115rps
30~115rps
30~76rps
30~46rps
SRK35ZJ-S
23~106rps
23~106rps
23~78rps
23~50rps
SRK50ZJ-S
30~115rps
30~115rps
30~72rps
30~42rps
SRK25ZJ-S
30~115rps
30~115rps
30~66rps
30~40rps
SRK20ZJ-S
Model
Fan speed
Auto
MED
HI
LO
(model DXK12 : 45)
35
35 (model DXK12 : 45)
(model DXK15 : ≧ − 2 ࠉ   ) (model DXK15 : 10 ࠉ   )
(model DXK15 : ≧
− 2 ࠉ)
5)
1)
2)
＜ − −
−
−
(ii)
1) 2) 3) 5)
16 minutes and 50 seconds (model SRK45 : 17 minutes operation
(model DXK15 : ＋10 ࠉ   )higher
met.
satisfied.
and 30 seconds).
(SRK45 : 10 )
Max. 16 minutes and 50 seconds
Heating operation
●

Defrost operation
(Mode SRK45: Max.17 minutes and 30 seconds)
Depends on an operation condition, the time can be longer than 7 minutes.
2-7 minutes 
Hot keep operation
(model SRK50 : 35)
(model SRK50 : 35)
(model SRK50 : 10 )
'09•SRK-DB-087D
(16)ࠉOutline of heating operation
(a) Operation of major functional components in heating mode
(b) Details of control at each operation mode (pattern)
(i) Fuzzy operation
(ii) Hot keep operation
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
(c) Defrost operation
(i)
1)
2)
3)
4)
5)
1)
2)
−
(ii)
Model
Fan speed
Auto
MED
HI
LO
ULO
*It can be set the indoor fan motor off or the heating thermostat OFF with connecting a wired remote control.
In the case, indoor air temperature is detected by sensor on the wired remote control.
During the heating operation, the indoor fan speed can be controlled based on the temperature of the indoor heat
exchanger (Th2) to prevent blowing out of cold air.
are satisfied.)
is satisfied.)
(Total compressor operation time)
After finish of defrost operation
C or less for 3 minutes continuously.
(Total compressor operation time)
20~115rps
20~115rps
20~86rps
20~70rps
20~44rps
SRK20ZS-S
20~115rps
20~115rps
20~104rps
20~84rps
20~54rps
SRK25ZS-S
20~115rps
20~115rps
20~108rps
20~96rps
20~60rps
SRK35ZS-S
23~106rps
23~106rps
23~82rps
23~70rps
23~37rps
SRK50ZS-S
Continued operation time of defrost operation →For more than 16 minutes and 50 seconds (model SRK50 : 18 minutes).
In case satisfied all of following conditions.
• Connect compressor speed 0 rps 10 times or more.
• Satisfy 1), 2) and 3) conditions above.
• Outdoor air temperature is 3°C or less.
is as following.

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27.5
25.5
18.0
18 30
(10) Outline of cooling operation
(a) Operation of major functional components in cooling mode
(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 between
the room temperature setting correction temperature and the suction air temperature.
ON OFF OFF
OFF OFF OFF
ON OFF
(few minutes ON)
OFF
(few minutes ON)
ON ON ON
Thermostat ON Thermostat OFF Failure
Cooling
Compressor
Indoor fan motor
Outdoor fan motor
4-way valve
15-74rps 20-97rps
15-74rps
15-98rps
15-98rps 20-97rps
15-52rps 15-74rps 20-72rps
15-38rps 15-46rps 20-44rps
Model
Fan speed SRK25ZSP-W SRK35ZSP-W SRK45ZSP-W
AUTO
MED
HI
LO
(11) 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
begins in the automatic operation.
Heating
Dehumidifying
Cooling
Indoor air temperature (˚C)
Outdoor air temperature (˚C)
(b) The unit checks the temperature every hour after the start of operation and, if the result of check is not same as the pre-
vious operation mode, changes the operation mode.
(i) If the setting temperature is changed with the remote control, the operation mode is judged immediately.
(ii) 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.
(iii) When the operation mode has been judged following the change of setting temperature with the remote control, the hour-
ly judgment of operation mode is cancelled.
(c) When the unit is started again within one hour after the stop of automatic operation or when the automatic operation is
selected 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
signals 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.
A
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

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(b) Dew prevention control Ⅱ[Cooling]
Prevents dewing on the indoor unit.
(i) Operating conditions
When the following conditions have been satised for more than 30 minutes after starting operation
1) Compressor speed is 32 rps or higher. (SRK25, 35)
2) Humidity is 68% or higher. (SRK45 : 60%)
(ii) Contents of operation
1) Air capacity control
Note (1) Ranges A and B are as shown below.
2) When this control has continued for more than 30 minutes continuously,the following wind direction control is per-
formed.
a) When the vertical wind direction is set at other than the vertical swing,the aps change to the horizontal position.
b) When the horizontal wind direction is set at other than the horizontal swing,the louver changes to the vertical po-
sition.
(iii) Reset condition
When any of followings is satised.
1) Humidity is less than 63%. (SRK45 : 55%)
(12) Protection control function
(a) Dew prevention control Ⅰ[Cooling]
Prevents dewing on the indoor unit.
(i) Operating conditions
When the following conditions have been satised.
1) Humidity is 78% or higher.
(ii) Contents of operation
Maximum compressor speed
SRK25ZSP-W 68 rps
SRK35ZSP-W 73 rps
SRK45ZSP-W 87 rps
(iii) Reset condition
When either of the following condition is satised.
1) Humidity is 73% or less.
2) Dew prevention control Ⅱ has been satised.
Humidity(%)
68 73
Range A
Range B
Model
Item SRK25,35ZSP-W SRK45ZSP-W
LO
Upper limit of compressor speed RangeA: 41rps, RangeB: 41rps RangeA: 57rps, RangeB: 39rps
Indoor fan 4th speed (SRK35 : 5th speed)
AUTO,HI,MED
Upper limit of compressor speed RangeA: 41rps, RangeB: 41rps RangeA: 57rps, RangeB: 39rps
Indoor fan Adaptable to compressor
speed (Lower limit 4th speed)