Mitsubishi Electric MSZ-HR25VF-E1 User manual

Models
MSZ-HR25VF -E1 , ER1 , ET1
MSZ-HR35VF -E1 , ER1 , ET1
MSZ-HR42VF -E1 , ER1 , ET1
MSZ-HR50VF -E1 , ER1 , ET1
INDOOR UNIT
No. OBH822
Outdoor unit service manual
MUZ-HR∙VF Series (OBH823)
PARTS CATALOG (OBB822)
CONTENTS
1. TECHNICAL CHANGES ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 2
2. PART NAMES AND FUNCTIONS∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 3
3. SPECIFICATION∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 4
4. NOISE CRITERIA CURVES ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 5
5. OUTLINES AND DIMENSIONS ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 6
6. WIRING DIAGRAM∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 7
7. REFRIGERANT SYSTEM DIAGRAM ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 8
8. SERVICE FUNCTIONS ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 10
9. MICROPROCESSOR CONTROL ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 12
10. TROUBLESHOOTING∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 16
11. DISASSEMBLY INSTRUCTIONS ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 29
SERVICE MANUAL
MSZ-HR25VF

2
Use the specied refrigerant only
Never use any refrigerant other than that specified.
Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of.
Correct refrigerant is specified in the manuals and on the spec labels provided with our products.
We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by
failure to follow the instructions.
TECHNICAL CHANGES
1
MSZ-HR25VF - E1 , ER1 , ET1
MSZ-HR35VF - E1 , ER1 , ET1
MSZ-HR42VF - E1 , ER1 , ET1
MSZ-HR50VF - E1 , ER1 , ET1
1. New model
<Preparation before the repair service>
Prepare the proper tools.
Prepare the proper protectors.
Provide adequate ventilation.
After stopping the operation of the air conditioner, turn off the power-supply breaker and remove the power plug.
Discharge the capacitor before the work involving the electric parts.
<Precautions during the repair service>
Do not perform the work involving the electric parts with wet hands.
Do not pour water into the electric parts.
Do not touch the refrigerant.
Do not touch the hot or cold areas in the refrigeration cycle.
When the repair or the inspection of the circuit needs to be done without turning off the power, exercise great caution not to
touch the live parts.
OBH822

3
PART NAMES AND FUNCTIONS
2
MSZ-HR25VF MSZ-HR35VF MSZ-HR42VF MSZ-HR50VF
ACCESSORIES
Model
MSZ-HR25VF
MSZ-HR35VF
MSZ-HR42VF
MSZ-HR50VF
Installation plate 1
Installation plate xing screw 4 × 25 mm 5
Wireless remote controller 1
Felt tape (For left or left-rear piping) 1
Battery (AAA) for remote controller 2
Operation indicator lamp
Remote control receiving section
Horizontal vane
Air inlet
Air filter
Front panel
Air outlet
Heat exchanger
Emergency operation switch
Air cleaning filter
(Silver-ionized
air purifier filter,
option)
Remote controller
OBH822

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SPECIFICATION
3
Indoor model MSZ-HR25VF MSZ-HR35VF MSZ-HR42VF MSZ-HR50VF
Power supply Single phase 230 V, 50 Hz
Electrical data
Power input
1
Cooling W20 28 32 39
Heating 20 28 32 39
Running
current 1
Cooling A0.20 0.27 0.30 0.36
Heating 0.20 0.27 0.30 0.36
Fan motor
Model RC0J30-CV
Current 1Cooling A0.20 0.27 0.30 0.36
Heating 0.20 0.27 0.30 0.36
Dimensions W × H × D mm 838 × 280 × 228
Weight kg 8.5 9.0
Special remarks
Air direction 5
Airow
Cooling
Super High
m3/h
582 702 786
High 432 468 648 672
Med. 324 336 522
Low 216 360 384
Heating
Super High 606 630 804 870
High 444 648 672
Med. 324 474 498
Low 198 336 366
Sound level
Cooling
Super High
dB(A)
43 46 45
High 37 38 39 40
Med. 30 31 34 36
Low 21 22 24 28
Heating
Super High 43 44 46 47
High 37 40 41
Med. 30 32 34
Low 21 24 27
Fan speed
Cooling
Super High
rpm
1,120 1,280 1,130
High 900 950 970 1,000
Med. 730 750 830 860
Low 550 630 660
Heating
Super High 1,150 1,180 1,150 1,220
High 920 970 1,000
Med. 730 770 800
Low 520 600 640
Fan speed regulator 4
Remote controller model RH18A
NOTE: Test conditions are based on IS 1391.
Cooling: Indoor Dry-bulb temperature 27°C Wet-bulb temperature 19°C
Outdoor Dry-bulb temperature 35°C Wet-bulb temperature 24°C
Heating: Indoor Dry-bulb temperature 20°C Wet-bulb temperature -
Outdoor Dry-bulb temperature 7°C Wet-bulb temperature 6°C
1 Measured under rated operating frequency.
Specifications and rated conditions of main electric parts
Model
Fuse (F11) T3.15AL250V
Horizontal vane motor (MV) 12 V DC
Varistor
(NR11) 470 V
Terminal block (TB) 3P
OBH822

5
NOISE CRITERIA CURVES
4
MSZ-HR25VF MSZ-HR35VF
MSZ-HR42VF MSZ-HR50VF
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
COOLING
FUNCTION SPL(dB(A)) LINE
45
HEATING 46
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
COOLING
FUNCTION SPL(dB(A)) LINE
45
HEATING 47
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
COOLING
FUNCTION SPL(dB(A)) LINE
43
HEATING 43
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
90
80
70
60
50
40
30
20
10 63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
BAND CENTER FREQUENCIES, Hz
COOLING
FUNCTION SPL(dB(A)) LINE
46
HEATING 44
OCTAVE BAND SOUND PRESSURE LEVEL, dB re 0.0002 MICRO BAR
Test conditions
Cooling: Dry-bulb temperature 27°C
Wet-bulb temperature 19°C
Heating: Dry-bulb temperature 20°C
Wet-bulb temperature -°C
INDOOR UNIT
WALL
MICROPHONE
0.8m
1m
OBH822

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OUTLINES AND DIMENSIONS
5
MSZ-HR25VF MSZ-HR35VF MSZ-HR42VF MSZ-HR50VF Unit: mm
OBH822

7
MSZ-HR25VF MSZ-HR35VF MSZ-HR42VF MSZ-HR50VF
WIRING DIAGRAM
6
OBH822

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REFRIGERANT SYSTEM DIAGRAM
7
Unit: mm
MSZ-HR25VF
MSZ-HR35VF
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11 Flared connection
Refrigerant flow in cooling
Refrigerant pipe ø9.52
(with heat insulator)
Refrigerant pipe ø6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Indoor coil
thermistor
RT13
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11 Flared connection
Refrigerant flow in cooling
Refrigerant pipe ø9.52
(with heat insulator)
Refrigerant pipe ø6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Indoor coil
thermistor
RT13
OBH822

9
Unit: mm
MSZ-HR42VF MSZ-HR50VF
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant flow in cooling
Refrigerant pipe ø9.52
(with heat insulator)
Refrigerant pipe ø6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Indoor coil
thermistor
RT13
OBH822

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MSZ-HR25VF MSZ-HR35VF MSZ-HR42VF MSZ-HR50VF
8-1. TIMER SHORT MODE
For service, the following set time can be shortened by bridging the timer short mode point on the electronic control P.C.
board. (Refer to 10-7.)
• The set time for the ON/OFF timer can be reduced to 1 second for each minute.
• After the breaker is turned on, the time for starting the compressor, which normally takes 3 minutes, can be reduced to 1
minute. Restarting the compressor, which takes 3 minutes, cannot be reduced.
SERVICE FUNCTIONS
8
Table 1
1 unit operation 2 units operation 3 units operation 4 units operation
No. 1 unit No modication Same as at left Same as at left Same as at left
No. 2 unit — Solder J2 Same as at left Same as at left
No. 3 unit — — Solder J4 Same as at left
No. 4 unit ———Solder both J2 and J4
How to set the remote controller exclusively for particular indoor unit
After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the remote
controller for the indoor unit.
The indoor unit will only accept the signal from the remote controller that has been assigned to the indoor unit once they are set.
The setting will be cancelled if the breaker is turned OFF, or the power supply is shut down.
Please conduct the above setting once again after the power has been restored.
J2 J4
The P.C. board has the print “J2” and “J4”. Solder “J2” and “J4” according to the number of indoor unit as shown in Table 1.
After modification, press the RESET button.
NOTE : For modification, take out
the batteries and press the
STOP/OPERATE/ (OFF/
ON) button 2 or 3 times at
first.
After finish modification,
put back the batteries then
press the RESET button.
8-2. P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
In this case, to operate each indoor unit individually by each remote controller, P.C. boards of remote controller must be
modified according to the number of the indoor unit.
How to modify the remote controller P.C. board
Remove batteries before modification.
The board has a print as shown below :
OBH822

11
8-3. AUTO RESTART FUNCTION
When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed
are memorized by the indoor electronic control P.C. board. “AUTO RESTART FUNCTION” automatically starts operation in
the same mode just before the shutoff of the main power.
Operation
If the main power has been cut, the operation settings remain.
After the power is restored, the unit restarts automatically according to the memory.
(However, it takes at least 3 minutes for the compressor to start running.)
How to disable “AUTO RESTART FUNCTION”
Turn off the main power for the unit.
Cut the jumper wire to JR77 on the indoor electronic control P.C. board. (Refer to 10-7.)
NOTE:
• The operation settings are memorized when 10 seconds have passed after the indoor unit was operated with the remote
controller.
• If main power is turned OFF or a power failure occurs while AUTO START/STOP timer is active, the timer setting is can-
celled.
• If the unit has been turned OFF with the remote controller before power failure, the auto restart function does not work as
the power button of the remote controller is OFF.
• To prevent the breaker from tripping OFF due to the rush of starting current, systematize other home appliance not to
turn ON at the same time.
• When some air conditioners are connected to the same supply system, if they are operated before power failure, the
starting current of all the compressors may flow simultaneously at restart.
Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting current
by adding to the system that allows the units to start one by one.
JR77
Indoor electronic
control P.C. board
CN111 CN151
GND
CN112
OBH822

12
WIRELESS REMOTE CONTROLLER
NOTE: Last setting will be stored after the unit is turned OFF with the remote controller. Indoor unit receives the signal of the
remote controller with beeps.
Operation Indicator lamp
The operation indicator at the right side of the indoor unit indicates the operation state.
•The following indication applies regardless of shape of the indication.
INDOOR UNIT DISPLAY SECTION
MSZ-HR25VF MSZ-HR35VF MSZ-HR42VF MSZ-HR50VF
STOP/OPERATE (OFF/ON) button
Fan speed control button
Operation select button
Timer mode select button
Signal transmitting section
Operation display section
Time set buttons
RESET button
Vane control button
Temperature buttons
ECONO COOL button
MICROPROCESSOR CONTROL
9
Indication Operation state Room temperature
The unit is operating to
reach the set temperature
About 2°C or more away
from set temperature
The room temperature is
approaching the set tem-
perature
About 1 to 2°C from set
temperature
Standby mode (only during
multi system operation)
-
Lit
Blinking
Not lit
OBH822

13
9-2. DRY ( ) OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select DRY mode with OPERATION SELECT button.
(3) The set temperature is determined from the initial room temperature.
1. Coil frost prevention
Coil frost prevention works the same way as that in COOL mode. (9-1.1.)
2. Low outside temperature operation
Low outside temperature operation works the same way as that in COOL mode. (9-1.2.)
9-1. COOL ( ) OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select COOL mode with OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button) to select the desired temperature. The setting range
is 16 - 31°C.
1. Coil frost prevention
The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the coil
from frosting.
When the temperature of indoor heat exchanger becomes too low, the coil frost prevention mode works.
The indoor fan operates at the set speed and the compressor stops. This mode continues until the temperature of indoor
heat exchanger rises.
2. Low outside temperature operation
When the outside temperature is lower, low outside temperature operation starts, and the outdoor fan slows or stops.
9-3. FAN( )OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
OPERATION INDICATOR lamp of the indoor unit turns ON with a beep tone.
(2) Select FAN mode with OPERATION SELECT button.
(3) Select the desired fan speed. When AUTO, it becomes Low.
Only indoor fan operates. Outdoor unit does not operate.
9-4. HEAT ( ) OPERATION
(1) Press STOP/OPERATE (OFF/ON) button.
OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone.
(2) Select HEAT mode with OPERATION SELECT button.
(3) Press TEMPERATURE buttons (TOO WARM or TOO COOL button) to select the desired temperature.
The setting range is 16 ~ 31°C.
1. Cold air prevention control
When the compressor is not operating or is starting, and the temperature of indoor heat exchanger and/or the room tem-
perature is low or when defrosting is being done, the indoor fan will stop or rotate in Very Low speed.
2. High pressure protection
The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the con-
densing pressure from increasing excessively.
When the temperature of indoor heat exchanger becomes too high, the high pressure protection works.
The indoor fan operates following the cold air prevention control. This mode continues until the temperature of indoor
heat exchanger falls.
3. Defrosting
Defrosting starts when the temperature of outdoor heat exchanger becomes too low.
The compressor stops once, the indoor/outdoor fans stop, the 4-way valve reverses, and the compressor re-starts.
This mode continues until the temperature of outdoor heat exchanger rises or the fixed time passes.
OBH822

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9-5. MULTI SYSTEM OPERATION
FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT: MXZ series
Multi system air conditioner can connect 2 or more indoor units with 1 outdoor unit.
• When you try to operate 2 or more indoor units with 1 outdoor unit simultaneously, one for the cooling and the oth-
ers for heating, the operation mode of the indoor unit that operates first is selected. Other indoor units cannot oper-
ate, and operation indicator lamp blinks as shown in the figure below. In this case, please set all the indoor units to
the same operation mode.
• When indoor unit starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes (max.
10 minutes) to blow out the warm air.
• In the heating operation, though indoor unit is not operating, it may get warm or the sound of refrigerant flow may
be heard. It is not malfunction. The reason is that the refrigerant continuously flows into it.
OPERATION INDICATOR
Lit
Blinking
Not lit
(7) SWING ( ) mode
By selecting SWING mode with VANE CONTROL button, the horizontal vane swings vertically.
(8) ECONO COOL ( ) operation (ECONOmical operation)
When ECONO COOL button is pressed in COOL mode, set temperature and the air flow direction is automati-
cally changed by the microprocessor. However, the temperature on the LCD screen on the remote controller is not
changed. Also the horizontal vane swings in various cycle.
SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher, the air
conditioner can keep comfort. As a result, energy can be saved.
To cancel this operation, select a different mode or press one of the following buttons in ECONO COOL operation:
ECONO COOL, VANE CONTROL button.
(5) STOP (operation OFF) and ON TIMER standby
In the following cases, the horizontal vane returns to the closed position.
(a) When STOP/OPERATE (OFF/ON) button is pressed (POWER OFF).
(b) When the operation is stopped by the emergency operation.
(c) When ON TIMER is ON standby.
(6) Dew prevention
During COOL or DRY operation with the vane angle at Angle 3 to 5 when the compressor cumulative operation time
exceeds 1 hour, the vane angle automatically changes to Angle 2 for dew prevention.
9-6. AUTO VANE OPERATION
1. Horizontal vane
(1) Vane motor drive
These models are equipped with a stepping motor for the horizontal vane. The rotating direction, speed, and angle of
the motor are controlled by pulse signals (approximately 12 V) transmitted from indoor microprocessor.
(2) The horizontal vane angle and mode change as follows by pressing VANE CONTROL button.
(AUTO) (1) (2) (3) (4) (5) (SWING)
(3) Positioning
To confirm the standard position, the vane moves until it touches the vane stopper. Then the vane is set to the
selected angle.
Confirmation of standard position is performed in the following cases:
(a) When the operation starts or finishes (including timer operation).
(b) When the test run starts.
(c) When standby mode (only during multi system operation) starts or finishes.
(4) VANE AUTO ( ) mode
In VANE AUTO mode, the microprocessor automatically determines the vane angle to make the optimum room tem-
perature distribution.
Horizontal
position
4
In COOL and DRY operation
Vane angle is fixed to Horizontal position.
In HEAT operation
Vane angle is fixed to Angle 4.
OBH822

15
9-7. TIMER OPERATION (ON/OFF TIMER)
1. How to set the timer
(1) Press STOP/OPERATE/ (OFF/ON) button to start the air conditioner.
(2) Select the timer mode by pressing the button during operation.
Each time this button is pressed, the timer mode is changed in sequence:
(OFF TIMER) → (ON TIMER) → TIMER RELEASE
(3) Set the time of the timer using the button.
Each time this button is pressed, the set time increase or decrease by 1 hour to 12 hours.
2. To release the timer
Press the button until (OFF TIMER) and (ON TIMER) are not displayed.
NOTE :
• The OFF TIMER and the ON TIMER cannot be set at the same time.
• The displayed time is the time remaining and will decrease in 1-hour increments as time passes.
9-8. EMERGENCY/TEST OPERATION
In the case of test run operation or emergency operation, use EMERGENCY
OPERATION switch in the right side of the indoor unit. Emergency operation
is available when the remote controller is missing or has failed, or when the
batteries in the remote controller are running down. The unit will start and
OPERATION INDICATOR lamp will light up.
The first 30 minutes of operation is the test run operation. This operation is
for servicing. The indoor fan runs at High speed and the temperature control
does not work.
After 30 minutes of test run operation, the system shifts to EMERGENCY
COOL/HEAT MODE with a set temperature of 24°C. The fan speed shifts to
Med.
The coil frost prevention works even in the test run or the emergency opera-
tion.
In the test run or emergency operation, the horizontal vane operates in
VANE AUTO ( ) mode.
Emergency operation continues until EMERGENCY OPERATION switch
is pressed once or twice or the unit receives any signal from the remote
controller. In the latter case, normal operation will start.
NOTE: Do not press EMERGENCY OPERATION switch during normal
operation.
Operation mode COOL/HEAT
Set temperature 24°C
Fan speed Med.
Horizontal vane Auto
The operation mode is indicated by the
Operation Indicator lamp as following
Operation Indicator lamp
EMERGENCY COOL
↓
EMERGENCY HEAT
↓
STOP
Lit
Not lit
EMERGENCY OPERATION switch
9-9. 3-MINUTE TIME DELAY OPERATION
When the system turns OFF, compressor will not restart for 3 minutes as 3-minute time delay function operates to protect
compressor from overload.
OBH822

16
10-1. CAUTIONS ON TROUBLESHOOTING
1. Before troubleshooting, check the following
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for miswiring.
2. Take care of the following during servicing
1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and after confirm-
ing the horizontal vane is closed, turn OFF the breaker and/or disconnect the power plug.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the P.C. board.
3) When removing the P.C. board, hold the edge of the board with care NOT to apply stress on the components.
4) When connecting or disconnecting the connectors, hold the connector housing. DO NOT pull the lead wires.
TROUBLESHOOTING
10
Lead wiring Connector housing
<Incorrect> <Correct>
MSZ-HR25VF MSZ-HR35VF MSZ-HR42VF MSZ-HR50VF
3. Troubleshooting procedure
1) Check if the OPERATION INDICATOR lamp on the indoor unit is blinking ON and OFF to indicate an abnormality.
To make sure, check how many times the OPERATION INDICATOR lamp is blinking ON and OFF before starting ser-
vice work.
2) Before servicing, check that the connector and terminal are connected properly.
3) When the electric control P.C. board seems to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
4) When troubleshooting, Refer to 10-2, 10-3 and 10-4.
NOTE: 1. If RESET button is not pressed, the remote controller may not operate correctly.
2. This remote controller has a circuit to automatically reset the microcomputer when batteries are replaced.
This function is equipped to prevent the microcomputer from malfunctioning due to the voltage drop caused by the
battery replacement.
3. Do not use the leaking batteries.
Press RESET button with a thin instrument, and
then use the remote controller.
Remove the front lid and insert batteries.
Then reattach the front lid.
4. How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
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17
10-2. FAILURE MODE RECALL FUNCTION
Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though LED indication listed on the troubleshooting check table (10-4.) disappears, the memorized failure details
can be recalled.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Does left lamp of OPERATION INDICATOR lamp
on the indoor unit blink at the interval of 0.5 sec-
onds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep is emitted at the same timing as
the blinking of left lamp of OPERATION
INDICATOR lamp. 2
Indoor unit is normal.
But the outdoor unit might be abnormal because there are some abnor-
malities that can not be recalled with this way.
Check if outdoor unit is abnormal according to the detailed outdoor unit
failure mode recall function.
No
Yes
Judgment of indoor/outdoor abnormality
Before blinking, does left lamp of OPERATION INDICA-
TOR lamp stay ON for 3 seconds?
Stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.
The indoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to the
table of indoor unit failure mode recall function. (Refer to 10-2.2)
Make sure to check at least 2 consecutive blinking cycles. 2
Releasing the failure mode recall function
Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring
to the table of outdoor unit failure mode recall function. (Refer to outdoor
unit service manual.)
Make sure to check at least 2 consecutive blinking cycles. 3
Repair the failure parts.
Deleting the memorized abnormal condition
After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall
function" mentioned above.
Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is displayed)
with the remote controller headed towards the indoor unit.
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
Release the failure mode recall function according to "Releasing the failure mode recall function"
mentioned above.
Yes
(Blinks)
No
(OFF)
NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly.
2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
2. Blinking pattern when the indoor unit is abnormal:
3.Blinking pattern when the outdoor unit is abnormal:
ON
OFF
Beeps
Repeated cycle Repeated cycle
ON
OFF
No beep Beeps
Repeated cycle
2.5-second OFF
Blinking at 0.5-
second interval
2.5-second OFF 3-second ON
Blinking at 0.5-
second interval
Beeps
Repeated cycle
2.5-second OFF
Blinking at 0.5-
second interval
No beep Beeps
Repeated cycle
2.5-second OFF 3-second ON
Blinking at 0.5-
second interval
Repeated cycle
Beeps
The cause of abnormality cannot be found because the abnormality does not recur.
Setting up the failure mode recall function
Turn ON the power supply.
<Preparation of the remote controller>
While pressing OPERATION SELECT button and TOO COOL button on the remote
controller at the same time, press RESET button.
First, release RESET button.
Hold down the other 2 buttons for another 3 seconds. Make sure that the indicators
on the LCD screen shown in the right gure are all displayed. Then release the but-
tons.
Press STOP/OPERATE (OFF/ON) button of the remote controller (the set temperature is
displayed) with the remote controller headed towards the indoor unit. 1
Operational procedure
1 Regardless of normal or abnormal condition,
a short beep is emitted once the signal is
received.
NOTE: It takes up to 1 minute to indicate the outdoor unit abnormality.
Even if the OPERATION INDICATOR lamp is not lighting, keep
checking at least 1 minute or longer.
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18
2. Table of indoor unit failure mode recall function
Left lamp of OPERA-
TION INDICATOR
lamp
Abnormal point
(Failure mode) Condition Remedy
Not lit Normal — —
1-time blink every
0.5-second
Room tempera-
ture thermistor
The room temperature thermistor short or
open circuit is detected every 8 seconds dur-
ing operation.
Refer to the characteristics of the room temperature
thermistor (10-7.).
2-time blink 2.5-sec-
ond OFF
Indoor coil
thermistor
The indoor coil thermistor short or open circuit
is detected every 8 seconds during operation.
Refer to the characteristics of the main indoor coil
thermistor, the sub indoor coil thermistor (10-7.).
3-time blink 2.5-sec-
ond OFF Serial signal The serial signal from outdoor unit is not re-
ceived for a maximum of 6 minutes.
Refer to 10-6. "How to check miswiring and serial
signal error".
11-time blink
2.5-second OFF Indoor fan motor
The rotational frequency feedback signal is not
emitted for the 12 seconds after the indoor fan
is operated.
Refer to 10-6. "Check of indoor fan motor".
12-time blink
2.5-second OFF
Indoor control
system
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
Replace the indoor electronic control P.C. board.
NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-4.).
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19
10-3. INSTRUCTION OF TROUBLESHOOTING
Indoor unit oper-
ates.
Outdoor unit
does not operate.
If blinking of OPERATION
INDICATOR lamp cannot be
checked, it can be checked
with failure mode recall
function.
Indoor unit operates.
Outdoor unit does
not operate normally.
Indoor unit does
not receive the
signal from re-
mote controller.
OPERATION INDICATOR
lamp on indoor unit is
blinking ON and OFF.
Outdoor unit
operates only
in Test Run
operation.
Outdoor unit
does not
operate even
in Test Run
operation.
Unit does not
operate nor-
mal operation
in COOL or
HEAT mode.
Indoor unit does
not operate, when
EMERGENCY
OPERATION
switch is pressed.
Indoor unit
operates, when
EMERGENCY
OPERATION
switch is pressed.
Check room
temperature
thermistor.
Refer to 10-
7. "Test point
diagram and
voltage".
Refer to "How
to check
inverter/com-
pressor".
Refer to
"Check of R.V.
coil".
Refer to 10-6.
"Check of remote
controller and
indoor electronic
control P.C. board".
1. Check indoor/outdoor connect-
ing wire.
2. Check if the power is supplied to
indoor unit.
• If power supply voltage is detected,
refer to 10-6. "Check of indoor
P.C. board and indoor fan motor".
• If power supply voltage is not
detected, refer to outdoor unit
service manual.
Left lamp
blink on and off
at 0.5-second
intervals
Cause:
Indoor/Outdoor
unit
• Miswiring or
trouble of serial
signal
Left lamp
2-time blink
Cause:
Indoor unit
• Trouble
of room
temperature
/ indoor coil
thermistor
Left lamp
3-time blink
Cause:
Indoor unit
• Trouble of
indoor fan
motor
Left lamp
4-time blink
Cause:
Indoor unit
• Trouble
of indoor
unit control
system
Left lamp
5-time blink
Cause:
Outdoor unit
• Outdoor
power sys-
tem abnor-
mality
Left lamp
6-time blink
Cause:
Outdoor unit
• Trouble of
thermistor in
outdoor unit
Left lamp
7-time blink
Cause:
Outdoor unit
• Trouble
of outdoor
control
system
Left lamp
14-time blink
or more
Cause:
Outdoor unit
• Other ab-
normality
Start
Refer to 10-
6. "How to
check mis-
wiring and
serial signal
error".
Check room
temperature
thermistor
and indoor
coil thermis-
tor. Refer to
10-7."Test
point diagram
and voltage".
Refer to 10-
6. "Check
of indoor fan
motor".
Replace the
indoor elec-
tronic control
P
.C. board.
Refer to
"How to
check
inverter/com-
pressor".
Refer to
"Check of
outdoor ther-
mistors".
Replace the
inverter P.C.
board or
the outdoor
electronic
control P.C.
board.
Check "Flow
chart of the
detailed
outdoor unit
failure mode
recall func-
tion."
"Test Run operation"
means the operation
within 30 minutes after
EMERGENCY OPERA-
TION switch is pressed.
Refer to outdoor unit
service manual.
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20
No. Abnormal
point Operation indicator lamp Symptom Condition Remedy
1
Miswiring
or serial
signal
Left lamp blinks .
0.5-second ON
0.5-second OFF
Indoor unit and
outdoor unit do
not operate.
The serial signal from the outdoor
unit is not received for 6 minutes.
• Refer to 10-6. "How to
check miswiring and serial
signal error".
2
Indoor coil
thermistor
Left lamp blinks .
2-time blink
2.5-second OFF
The indoor coil or the room tem-
perature thermistor is short or
open circuit.
• Refer to the characteristics
of indoor coil thermistor, and
the room temperature ther-
mistor (10-7.).
Room tem-
perature
thermistor
3Indoor fan
motor
Left lamp blinks .
3-time blink
2.5-second OFF
The rotational frequency feedback
signal is not emitted during the
indoor fan operation.
• Refer to 10-6. "Check of
indoor fan motor".
4Indoor con-
trol system
Left lamp blinks .
4-time blink
2.5-second OFF
It cannot properly read data in the
nonvolatile memory of the indoor
electronic control P.C. board.
• Replace the indoor electronic
control P.C. board.
5
Outdoor
power sys-
tem
Left lamp blinks .
5-time blink
2.5-second OFF
It consecutively occurs 3 times
that the compressor stops for
overcurrent protection or start-up
failure protection within 1 minute
after start-up.
• Refer to "How to check of
inverter/compressor".
Refer to outdoor unit service
manual
• Check the stop valve.
6Outdoor
thermistors
Left lamp blinks .
6-time blink
2.5-second OFF
The outdoor thermistors short or
open circuit during the compressor
operation.
• Refer to "Check of outdoor
thermistor".
Refer to outdoor unit service
manual.
7
Outdoor
control sys-
tem
Left lamp blinks .
7-time blink
2.5-second OFF
It cannot properly read data in the
nonvolatile memory of the inverter
P.C. board or the outdoor elec-
tronic control P.C. board.
• Replace the inverter P.C.
board or the outdoor elec-
tronic control P.C. board.
Refer to outdoor unit service
manual.
8Other ab-
normality
Left lamp blinks .
14-time blink or more
2.5-second OFF
An abnormality other than above
mentioned is detected.
• Check the stop valve.
• Check the 4-way valve.
• Conrm the abnormality in
detail using the failure mode
recall function for outdoor
unit.
9
Outdoor
control sys-
tem
Upper lamp lights up
Outdoor unit
does not oper-
ate
It cannot properly read data in the
nonvolatile memory of the inverter
P.C. board.
• Check the blinking pattern of
the LED on the inverter P.C.
board.
10-4. TROUBLESHOOTING CHECK TABLE
Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
When the indoor unit has started operation and detected an abnormality of the following condition (the first detection after the
power ON), the indoor fan motor turns OFF and OPERATION INDICATOR lamp blinks.
Lit
Blinking
Not lit
OPERATION INDICATOR
OBH822