Midea MFJ-24ARN1-QB8 Operating manual

Model:
MFJ-24ARN1-QB8
MFJ-48ARN1-RB6
Floor Standing Type Air Conditioner

Content
CONTENT
1 Safety Precautions.......................................................................................... 1
1.1 Precaution .................................................................................................................... 1
1.2 Installation ................................................................................................................... 1
1. Caution ......................................................................................................................... 1
1.4 Operational .................................................................................................................. 1
3 Out Dimensions............................................................................................... 3
.1 Indoor Unit ...................................................................................................................
.2 Outdoor Unit ................................................................................................................. 4
4 External view and display............................................................................... 5
4.1 External view ................................................................................................................ 5
4.2 Display panel ............................................................................................................... 6
5 Refrigerant cycle diagram .............................................................................. 7
5.1 Cooling only .................................................................................................................. 7
5.2 Heat pump mode ......................................................................................................... 7
6 PCB drawing & wiring diagram...................................................................... 8
6.1 MFJ-24ARN1-QB8 ........................................................................................................ 8
6.2 MFJ-48ARN1-RB6 ........................................................................................................ 9
7 Installation detail ........................................................................................... 10
7.1 Installation place ....................................................................................................... 10
7.2 Installing ..................................................................................................................... 11
7. Refrigerant pipe connecting .....................................................................................1
7.4 Drain Pipe of The Indoor Unit ...................................................................................15
7.5 Wiring .........................................................................................................................15
7.6 Test operation ............................................................................................................ 16
8 Electronic function........................................................................................ 17
8.1 Performance Index .................................................................................................... 17
8.2 Main data Introduction.............................................................................................. 17
8. Operation Modes and Functions .............................................................................. 17
8.4 Other Functions .........................................................................................................19
9 Characteristic of temperature sensor ......................................................... 20
10 Trouble shooting ........................................................................................... 21
10.1 Protective Function .................................................................................................... 21
10.2 Self-diagnosis ............................................................................................................ 21
10. Troubles and Solutions ............................................................................................. 22

Safety Precautions
1
1 Safety Precautions
1.1 Precaution
To prevent injury to the user or other people and property damage, the following instructions
must be followed.
Incorrect operation due to ignoring instruction will cause harm or damage.
Before service unit, be sure to read this service manual at first.
1.2 Installation
For electrical work, contact the dealer, seller, a qualified electrician, or an Authorized service
center.
Do not disassemble or repair the product by yourself.
Sharp edges could cause injury, be especially careful of the case edges and the fins on the
condenser and evaporator.
Be sure the installation area does not deteriorate with age.
Take care to ensure that power cable could not be pulled out or damaged during operation.
Do not place anything on the power cable.
Do not plug or unplug the power supply plug during operation.
Do not store or use flammable gas or combustible near the product.
When flammable gas leaks, turn off the gas and open a window for ventilation before turn the
product on.
If strange sounds, or small or smoke comes from product. Turn the breaker off or disconnect the
power supply cable as soon as possible.
When the product is soaked (flooded or submerged), contact an Authorized service center.
Be caution that water could not enter the product.
Turn the main power off when cleaning or maintaining the product.
When the product is not be used for a long time, disconnect the power supply plug or turn off the
breaker.
1.3 Caution
Always check for gas (refrigerant) leakage after installation or repair of product.
Install the drain hose to ensure that water is drained away properly.
Keep level even when installing the product.
Do not install the product where the noise or hot air from the outdoor unit could damage the
neighborhoods.
Use two or more people to lift and transport the product.
Do not install the product where it will be exposed to sea wind (salt spray) directly.
1.4 Operational
Do not expose the skin directly to cool air for long periods of time. (Do not sit in the draft).
Do not use the product for special purposes, such as preserving foods, works of art, etc. It is a
consumer air conditioner, not a precision refrigerant system.
Do not block the inlet or outlet of air flow.
Use a soft cloth to clean. Do not use harsh detergents, solvents, etc.

Safety Precautions
2
Do not touch the metal parts of the product when removing the air filter. They are very sharp.
Do not step on pr put anything on the product. (outdoor units)
Always insert the filter securely. Clean the filter every two weeks or more often if necessary.
Do not insert hands or other object through air inlet or outlet while the product is operated.
Do not drink the water drained from the product.
Use a firm stool or ladder when cleaning or maintaining the product.
Replace the all batteries in the remote control with new ones of the same type. Do not mix old
and mew batteries or different types of batteries.
Do not recharge or disassemble the batteries. Do not dispose of batteries in a fire.
If the liquid from the batteries gets onto your skin or clothes, wash it well with clean water. Do not
use the remote of the batteries have leaked.

Outer Dimensions
3
2 Out Dimensions
2.1 Indoor Unit
Dimension
Mode
Width
(mm)
Height
(mm)
Depth
(mm)
24K 500 1700 290
48K 540 1825 410

Outer Dimensions
4
2.2 Outdoor Unit
Dimension
Mode
W idth
(mm)
Height
(mm)
Depth
(mm)
A
(mm)
B
(mm)
24K
840
695
5
560
5
Dimension
Mode
W idth
(mm)
Height
(mm)
Depth
(mm)
A
(mm)
B
(mm)
48K
940
1245
60
602
80

External view and display
5
3 External view and display
3.1 External view
1
2
3
4
5
6
7
8
11
10
9
Outd oo r unit
1
Air outlet
2
Operation panel
3
Horizo ntal airflow control louver
4
Vertic al airflow co ntrol louver
5
Remote controller holder(on some models)
6
Air inl et(2 sides)
7
Drain pipe, vent pip e
8
Connection cable
9
Connection pipe
10
Refrigerant pipe po rt
11
Air outle t
Indoor unit
Note: All the pictures in this manual are for explanation purpose only. They may be slightly
different from the air conditioner you purchased(depend on model). The actual shape shall prevail.

External view and display
6
3.2 Display panel
auto
T2
T3
T4 T1
OFF
ON
AUX ILIARY
FU N CTION
M ODE
FAN
S PEED
A DJU ST
M ODE
A DJU ST
LOC K
TE ST
RUN N ING
O N/ OF F
12 3 4 5 6
57
Indicators
Auto operation display
Cool ing operation display
Dry o peration display
Heating operation disp lay
Fan operation display
Vert ical airflow display
Hori zontal airflow disp lay
Slee p operation display
Turbo operation displa y
On t imer operation display
Off t ime r operation dis play
Lock operation display
Fan speed
operation d isplay
Room Te mp/Set Temp
/Set Tim er display

Refrigerant cycle diagram
7
4 Refrigerant cycle diagram
4.1 Cooling only
4.2 Heat pump mode

PCB drawing & Wiring diagram
8
5 PCB drawing & wiring diagram
5.1 MFJ-24ARN1-QB8
Indoor unit
Outdoor unit

PCB drawing & Wiring diagram
9
5.2 MFJ-48ARN1-RB6
Indoor unit
Outdoor unit

Installation detail
10
6 Installation detail
6.1 Installation place
6.1.1 Indoor Unit
A place which provides the spaces around the indoor unit as required above in the diagram.
A place where is no obstacle near the inlet and outlet area.
A place which can bear the weight of the indoor unit.
A place which allows the air filter to be removed downward.
A place where the reception range is not exposed to direct sunlight.
In the center of the room where possible.
6.1.1.1 Please stand the unit in hard and flat ground;
Please reserve space for installation and maintenance.
6.1.1.2 Please check the elevation difference between the indoor unit and the
outdoor unit, the length of the refrigerant pipe, and the curved places (bend) of
the pipe are no more than the following numbers:Elevation difference: no more
than 10 M (if the elevation difference between indoor and outdoor unit is more
than 10 meters, it is recommended that the outdoor unit be placed above
the indoor unit.)
Pipe length: no more than 20 M
Bends: no more than 5 places
6.1.2 Outdoor Unit
6.1.2.1 Before installing the outdoor unit, you should:
Select a place where no direct sunlight or other heat-radioactivity may reach. A sunshade is
needed if it is unavoidable.
Select a place that is easy to connect indoor unit's pipe and electric wires.
Avoid a place where combustible gas may leak or stay.
Keep it in mind that water may drain out of the outdoor unit while in "Heat" mode.

Installation detail
11
6.1.2.2 If the outdoor unit is to be installed on a roof or where no constructions are
around, you should avoid hard wind blows directly to the air outlet, because it
may cause trouble for air-flow shortage.
6.1.2.3 Reserve enough space for installation, maintenance and unit-functioning.
Remove as many obstacles as possible nearby.
6.2 Installing
6.2.1 To prevent the indoor unit from falling, you must:
Pay full attention to the unit because its long outer shape makes it easy to fall;
Safety Lock
Screws
.9 25 ×
M8 Screws
Screws
.9 25 ×
Air Outlet
Air Inlet Screw hole
(on the unit
)
2
Firmly fix the unit to the wall and in the ground to avoid accidental falling.
6.2.2 Dismounting the air-inlet grid
Please take off the air-inlet grid before connecting the pipes/wires.
Pull down the two knobs on the grid, take off the two screws, then the air-inlet grid goes free.

Installation detail
12
6.2.3 Take the Pipe Clip off before connecting the pipes and wiring; fit it when these
finished.
Use accessories 4 and 9 to connect the pipes/wires on both sides and back side.
Drain Pipe
Reamer Joint
Pipe/wire-hole positions on both sides
Wiring
Hole 5 φ
Refrigerant/drain
Pipe hole 80 φ
Reamer Joint
Refrigerant Pipe
Pipe/wire-hole position on the bottom
Wiring
Hole 5 φ
Refrigerant/drain
Pipe hole
Refrigerant/drain
Pipe hole
6.2.4 Ship the a/c to the installation place originally packed;
Be careful while hanging the unit because the center of gravity of the unit is not centralized;
Do not make the angle of inclination more than 45 degrees while shipping;(Avoid horizontal
storage)
Be sure the electric insulation work is well done if installed on metal ceiling / wall.
Fix the unit feet with bolts (M10/M8). Be sure the unit is fixed strongly enough to against blast or
earthquake.

Installation detail
13
Make a concrete basement to the unit by the above references.
6.3 Refrigerant pipe connecting
6.3.1 Pipe length and the elevation
The correct refrigerant quantity filled in the 5-meter-long pipe of the outdoor unit is marked on
the Product Data Plate. If you have to use longer pipe for every meter plus pipe, the refrigerant
should be added according to the following calculation.
Standard
length
Max. Max. A dditional
(m) E levation E levation refrig erant
Btu/h GAS LIQUID B (m) A (m) (g/m)
24K
5/8’’ (φ16)
1/4’’ (φ9.5 )
5
10
20
65
48K
/4’’ (φ19)
1/2’’ (φ12.7)
5
15
0
90
Pipe sizeC apacity
6.3.2 Piping connection
6.3.2.1 Connecting Of Refrigerant Pipe
a. Only the correctly installing of indoor and outdoor unit done, can the refrigerant pipe be connected.
b. The cut-off valves are completely close before ex-work. Before connecting the refrigerant pipe, be
careful to check whether the valves are completely close.
c. The connecting procedure of refrigerant pipe: first, unscrew the two valves on the outdoor unit and
the pipe-jointing nut on the indoor unit(please keep them care fully). Please connect the refrigerant
pipe according to the manual, the pipe-jointing nut should be screw tightly and no leakage. Note:
you need two wrenches to make balance.
d. When the connecting of refrigerant pipe is finished, before power on the system, you should

Installation detail
14
vacuum the indoor unit through the maintenance port on the cut-off valves, or open the
high-pressure valve, and exhaust the air through the maintenance port on the low-pressure
valve(closed). It will take about ten seconds. Then screw tightly the maintenance port. (When
supplement the refrigerant, fill through the maintenance port of the low-pressure valves on the
outdoor unit ).
e. Open all the valves completely before power on the system, or it will be sick for low efficiency.
f. Gas leak check. Make sure no gas from connections with leak detector or soap water.
6.3.2.2 Using bronze pipe selling in market
Completely shut the cut-off valves of the outdoor unit (as ex-work status). After the refrigerant
pipe has been connected with both the indoor and outdoor unit, let the air exhaust out from the
maintenance gap on he low-pressure cut-off valves of the outdoor unit. Screw the nuts tightly
on the maintenance gap after the air has been drained.
6.3.2.3 To make the refrigerant pipe unblocked completely
you should keep the cut-off valves of the outdoor unit completely open after you have finished
the above steps (step1) or step 2))
Note: Before screwing the reamer nut, smear the pipe and the connecting surface with
refrigerant oil; Check and make sure there is no leakage by soap-water or leakage-checker after
connecting;
Be sure the connecting joint on the indoor side is insulated.
Use two wrenches to connecting the pipes.
Tubing size Torque
9.52 3270~3990N.cm(333~407kgf.cm)
12.7 4950~6030N.cm(504~616kgf.cm)
16 6180~7540N.cm(630~770kgf.cm)
19 9720~11860N.cm(990~12106kgf.cm)
6.3.3 Air Purging
When Using the Vacuum Pump
(For method of using a manifold valve, refer to its operation manual.)
a. Completely tighten the flare nuts, A, B, C, D, connect the manifold valve charge hose to a
charge port of the low-pressure valve on the gas pipe side.
b. Connect the charge hose connection to the vacuum pump.
c. Fully open the handle Lo of the manifold valve.
d. Operate the vacuum pump to evacuate. After starting evacuation, slightly loose the flare nut of
the Lo valve on the gas pipe side and check that the air is entering.(Operation noise of the
vacuum pump changes and a compound meter indicates 0 instead of minus)
e. After the evacuation is complete, fully close the handle Lo of the manifold valve and stop the
operation of the vacuum pump. Make evacuation for 15 minutes or more and check that the
compound meter indicates -76cmHg (-10x106Pa).

Installation detail
15
f. Turn the stem of the packed valve B about 45 counterclockwise for 6~7 seconds after the gas
coming out, then tighten the flare nut again. Make sure the pressure display in the pressure
indicator is a little higher than the atmosphere pressure.
g. Remove the charge hose from the low pressure charge hose.
h. Fully open the packed valve stems B and A.
i. Securely tighten the cap of the packed valve.
6.4 Drain Pipe of The Indoor Unit
Make sure the drainpipe is connected to the outdoor side downward;
The hard polyvinyl chloride(PVC)plastic pipe (external diameter 26 mm) sold is the market is
suitable for the attached soft drain pipe;
Please connect the Soft Drain Pipe with the Drain Pipe, then fix it with band;
If you have to connect the Drain Pipe indoors, to avoid condensing caused by air intake, you
must cover the pipe with heat-insulation material (polyethylene with Specific Gravity of 0.03, at least
9 mm in thickness), and use Glue Band to fix it.
After the Drain Pipe has been connected, please check if the water drains out of the pipe
efficiently and has no leakage.
Refrigerant pipe and Drainpipe should be heat-insulated to avoid condensing and
water-dropping later on.
6.5 Wiring
Please refer to the Wiring Diagram.

Installation detail
16
(Wiring size: 2.5mm ) ≥
2
(Wiring size: 2.5mm ) ≥
2
Note: Some models is equipped with a cord having a plug, So a wall outlet shall be properly
installed.
6.6 Test operation
Perform test operation after completing gas leak and electrical safety check. The test operation
time should last more than 30 minutes.
1). Open the panel and lift the panel up to angle which remains fixed. Do not lift the panel any
further when it stops with a "click"sound.
2). Press the manual switch button twice until the operation indicator lights, the unit will operate on
Manual Cool mode.
3). Check if all the functions work well while testing the air conditioner. Especially check whether
the drainage of indoor unit is smooth or not.
4). Press the manual switch button again till the operation indicator turns dark after finishing the
test operation and the unit stops operation.

Electronic function
17
7 Electronic function
7.1 Performance Index
No. Item Index
1 Applicable Voltage Range 185-253V, 342-418V
2 A/C Frequency 50Hz
3 Working environment temperature -7°C- +45°C
7.2 Main data Introduction
Ts : Set temperature,
T1 : Room temperature
T2: Evaporator pipe temperature
7.3 Operation Modes and Functions
7.3.1 Manual Operation
7.3.2 Heating Mode
7.3.2.1 Four-way valve opens at once, while defrosting process closes.
7.3.2.2 Condition for the compressor action: (Ts=set temperature, T1=room
temperature)
7.3.2.3 Indoor Fan Action
Anytime remote switchover for fan speed among high/low/auto, anti-cold air function takes
priority.
Auto fan in heating mode
Anti-cold air:
Switchover between fan speed and fine tune can be set according to temperature of evaporator
pipe (T2).
Condition Compressor and outdoor fan
Room temperature up T1-Ts=0°C Off
T1-Ts>-1°C On
Room temperature down T1-Ts<-1°C On
T1-Ts=0°C Off
Condition Fan speed
Room temperature up T1-Ts>-1°C Low
T1-Ts<-1°C Hi.
Room temperature down T1-Ts<-2°C Hi.
-2°C <T1-Ts <-1°C Low
Condition Fan speed
Room temperature up T2<25°C Off
25°C <T2<32°C Low
T2>32°C Set fan speed
Room temperature down T2>22°C Set fan speed
20°C <T2<22°C Low

Electronic function
18
7.3.3 Defrost (only available to heating mode)
7.3.3.1 Defrosting Conditions
Starting Of Defrosting Condition (meet one of the following is ok):
(1)Accumulated compressor operating time when temperature of outdoor heat exchanger coil
T3 is below -2°C reaches up to over 46 minutes.(When T3 is over 20°C, calculate time again.)
(2) Under evaporator high temperature protection, the accumulated time when outdoor fan
motor is off and compressor is on reaches up to over 90 minutes .(When T3 is over 20°C, calculate
time again.)
High temperature defrosting condition:
Under high temperature protection of evaporator, the time when outdoor fan is shut down but
compressor is not has been accumulated for up to 90 minutes.
7.3.3.2 Defrosting Action
Four-way valve, indoor fan, outdoor fan are shut down. Compressor keeps on.
7.3.3.3 Ending Of Defrosting Condition (meet one of the following is ok):
(1)Time of defrosting lasts 10 minutes.
(2)Temperature of outdoor coil T3 is up to 20°C.
7.3.4 Cooling Mode
7.3.4.1 Four-way valve is closed.
If four-way valve is open before the machine enters cooling mode, then four-way valve will be
closed at the first time, the compressor starts under the cooling mode.
7.3.4.2 Conditions for the compressor and outdoor fan action (Ts = set temperature)
7.3.4.3 Action of Indoor Fan
HIGH/LOW/AUTO fan can be switched over by your comfort.
Auto fan under cooling mode.
7.3.5 Dehumidifying Mode
7.3.5.1 Indoor fan speed is low.
7.3.5.2 If certain protective condition is met, operation will be carried out.
T2<20°C Off
Condition Compressor and outdoor fan
Room temperature up T1-Ts=0°C Off
T1-Ts>1°C On
Room temperature down T1-Ts>0°C On
T1-Ts=0°C Off
Condition Fan speed
Room temperature up T1-Ts>2°C Hi.
1°C < T1-Ts <2°C Low
Room temperature down T1-Ts>1°C Hi.
T1-Ts <1°C Low