Mitsubishi Electric MS-GF20VA-E1 User manual

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············································ 6
7. REFRIGERANT SYSTEM DIAGRAM ··············· 7
8. SERVICE FUNCTIONS ····································· 8
9. MICROPROCESSOR CONTROL ··················· 10
10. TROUBLESHOOTING····································· 15
11. DISASSEMBLY INSTRUCTIONS ···················· 25
SPLIT-TYPE AIR CONDITIONERS
Outdoor unit service manual
MU-GF·VA Series (OBH622)
SERVICE MANUAL No. OBH621
INDOOR UNIT
PARTS CATALOG (OBB621)
NOTE:
RoHS compliant products have <G> mark on the spec name plate.
Models
MS-GF20VA -E1
MS-GF25VA -E1
MS-GF35VA -E1

2
MS-GF20VA - E1
MS-GF25VA - E1
MS-GF35VA - E1
1. New model
TECHNICAL CHANGES
1
Use the specified 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.
<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.
OBH621

3
ACCESSORIES
PART NAMES AND FUNCTIONS
2
Model
MS-GF20VA
MS-GF25VA
MS-GF35VA
Installation plate 1
Installation plate fixing screw 4 × 25 mm 5
Remote controller holder 1
Fixing screw for 3.5 × 16 mm (Black) 2
Battery (AAA) for remote controller 2
Wireless remote controller 1
Felt tape (For left or left-rear piping) 1
MS-GF20VA MS-GF25VA MS-GF35VA
Air filter
(Nano platinum filter)
Front panel
Air cleaning filter
(Electrostatic anti-allergy
enzyme filter, option)
Operation indicator lamp
Remote control receiving section
Emergency operation switch (E.O. SW)
Horizontal vane
Air outlet Heat exchanger
Display section
Air inlet
Remote controller
OBH621

4
SPECIFICATION
3
Indoor model MS-GF20VA MS-GF25VA MS-GF35VA
Function Cooling
Power supply Single phase 230 V, 50 Hz
Electrical
data
Running current A 0.20 0.22
Power input W 35 43
Fan motor
Model RC4V18-FA
Current A 0.20 0.22
Dimensions W × H × D mm 798 x 295 x 232
Weight kg 9
Special remarks
Air direction 5
Airflow
Super High (POWERFUL)
m3/h
558 624
High 474 558
Med. 378 396
Low 246 288
Sound level
Super High (POWERFUL)
dB (A)
40 44
High 36 40
Med. 31 33
Low 25 26
Fan speed
Super High (POWERFUL)
rpm
1,000 1,100
High 880 1,000
Med. 740 770
Low 540 610
Fan speed regulator 4
Remote controller model KM12A
NOTE: Test conditions are based on ISO 5151.
Cooling: Indoor Dry-bulb temperature 27 Wet-bulb temperature 19
Outdoor Dry-bulb temperature 35 Wet-bulb temperature 24
Indoor-Outdoor piping length: 5 m
OBH621

5
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
Super High
FAN SPEED
40
NC-10
OCTAVE BAND SOUND PRESSURE LEVEL, 0dB 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
Super High
FAN SPEED
40
NC-10
OCTAVE BAND SOUND PRESSURE LEVEL, 0dB re 0.0002 MICRO BAR
Test conditions
Cooling: Dry-bulb temperature 27 °C
Wet-bulb temperature 19 °C
INDOOR UNIT
WALL
MICROPHONE
0.8m
1m
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
Super High
FAN SPEED
44
NC-10
OCTAVE BAND SOUND PRESSURE LEVEL, 0dB re 0.0002 MICRO BAR
NOISE CRITERIA CURVES
4
MS-GF20VA MS-GF25VA
MS-GF35VA
OBH621

6
Unit: mm
OUTLINES AND DIMENSIONS
5
211.5
231.5
253
21.5
155 155
80
80 225 225
3
5232
56
69
798
785 6.5
130619
50
295
50
42
56
43
42
8
100
107
112
45
56
69
33861
212.5
254
41
42
315 84
11×26 Oblong hole 11×20 Oblong hole
Installation plate
Indoor unit
Wall hole ø65
Air in
Air out
Installation plate
Piping
Drain hose
159
19
58
MS-GF20VA MS-GF25VA MS-GF35VA
Piping
Insulation ø35 O.D
Liquid line ø7 - 0.5 m (Flared connection ø6.35)
Gas line ø9.52 - 0.43 m (Flared connection: ø9.52)
Drain hose Insulation ø28 O.D Connected part ø16 O.D
WIRING DIAGRAM
6
MS-GF20VA MS-GF25VA MS-GF35VA
OBH621

7
Unit: mm
REFRIGERANT SYSTEM DIAGRAM
7
MS-GF20VA MS-GF25VA
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe 6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Refrigerant flow in cooling
Refrigerant pipe 9.52
(with heat insulator)
MS-GF35VA
Indoor
heat
exchanger
Flared connection
Room temperature
thermistor
RT11
Flared connection
Refrigerant pipe 6.35
(with heat insulator)
Indoor coil
thermistor
RT12
Refrigerant flow in cooling
Refrigerant pipe 9.52
(with heat insulator)
OBH621

8
8-1. TIMER SHORT MODE
For service, the following set time can be shortened by short circuit of JPG and JPS on the electronic control P.C. board.
(Refer to 10-7.)
Set time: 3 minutes →3 seconds (It takes 3 minutes for the compressor to start operation. However, the starting time is
shortened by short circuit of JPG and JPS.)
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:
NOTE: For modification, take out
the batteries and press
the OPERATE/STOP (ON/
OFF) button 2 or 3 times at
first.
After modification, put back
the batteries then press the
RESET button.
J2
J1
Table 1
1 unit operation 2 units operation 3 units operation 4 units operation
No. 1 unit No modification Same as at left Same as at left Same as at left
No. 2 unit — Solder J1 Same as at left Same as at left
No. 3 unit — — Solder J2 Same as at left
No. 4 unit — — — Solder both J1 and J2
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 restored.
SERVICE FUNCTIONS
8
MS-GF20VA MS-GF25VA MS-GF35VA
The P.C. board has the print “J1” and “J2”. Solder “J1” and “J2” according to the number of indoor unit as shown in Table 1.
After modification, press the RESET button.
OBH621

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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.
Solder the jumper wire to JR07 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 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 breaker 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.
JR07
Indoor electronic
control P.C. board
111NCA01NC 151NC 211NC
OBH621

10
WIRELESS REMOTE CONTROLLER
MICROPROCESSOR CONTROL
9
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.
Signal transmitting section
Operation display section
Temperature buttons
OPERATE/STOP
(ON/OFF) button
Indication of
remote controller
model is on back
TIME SET buttons
FORWARD button
BACKWARD button
VANE CONTROL button
OFF-TIMER button
RESET button
FAN SPEED CONTROL button
OPERATION SELECT button
ECONO COOL button ON-TIMER button
CLOCK button
POWERFUL COOL button
MS-GF20VA MS-GF25VA MS-GF35VA
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.
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
INDOOR UNIT DISPLAY SECTION
Lighted
Blinking
Not lighted
9-1. COOL ( ) OPERATION
(1) Press OPERATE/STOP (ON/OFF) 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.
OBH621