Midea MSMTAU-09HRFN8-QRD6GW Service Manual
Ultimate Comfort 3D Inverter Series
Service Manual 2017
R32
CONTENTS
1. Precaution .................................................................................................................................................... 1
1.1 Safety Precaution ........................................................................................................................ 1
1.2 Warning ....................................................................................................................................... 1
2 Information servicing ................................................................................................................................... 4
3. Model List ..................................................................................................................................................... 8
4. Dimension .................................................................................................................................................... 9
4.1 Indoor Unit ................................................................................................................................... 9
4.2 Outdoor Unit .............................................................................................................................. 11
5. Refrigerant Cycle Diagram ....................................................................................................................... 13
6 Installation Details ...................................................................................................................................... 14
6.1 Wrench torque sheet for installation .......................................................................................... 14
6.2 Connecting the cables ............................................................................................................... 14
6.3 Pipe length and the elevation .................................................................................................... 15
6.4 Installation for the first time........................................................................................................ 16
6.5 Adding the refrigerant after running the system for many years ................................................ 17
6.6 Re-installation while the indoor unit need to be repaired ........................................................... 17
6.7 Re-installation while the outdoor unit need to be repaired ......................................................... 18
7. Operation Characteristics ......................................................................................................................... 20
8. Wiring Diagram .......................................................................................................................................... 21
8.1 Indoor Unit ................................................................................................................................. 21
8.2 Outdoor Unit .............................................................................................................................. 22
9. Electronic function .................................................................................................................................... 23
9.1 Abbreviation .............................................................................................................................. 23
9.2 Display function ......................................................................................................................... 23
9.3 Main Protection ......................................................................................................................... 24
9.4 Operation Modes and Functions ............................................................................................... 25
10. Troubleshooting ....................................................................................................................................... 32
10.1 Indoor Unit Error Display ......................................................................................................... 33
10.2 Trouble shooting ...................................................................................................................... 34
1
1. Precaution
1.1 Safety 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 the unit, be sure to
read this service manual at first.
1.2 Warning
Installation
Do not use a defective or underrated
circuit breaker. Use this appliance on a
dedicated circuit.
There is risk of fire or electric shock.
For electrical work, contact the dealer,
seller, a qualified electrician, or an
authorized service center.
Do not disassemble or repair the product,
there is risk of fire or electric shock.
Always ground the product.
There is risk of fire or electric shock.
Install the panel and the cover of
control box securely.
There is risk of fire of electric shock.
Always install a dedicated circuit and
breaker.
Improper wiring or installation may cause fore
or electric shock.
Use the correctly rated breaker of
fuse.
There is risk of fire or electric shock.
Do not modify or extend the power
cable.
There is risk of fire or electric shock.
Do not install, remove, or reinstall the
unit by yourself (customer).
There is risk of fire, electric shock, explosion,
or injury.
Be caution when unpacking and
installing the product.
Sharp edges could cause injury, be especially
careful of the case edges and the fins on the
condenser and evaporator.
For installation, always contact the
dealer or an authorized service center.
Do not install the product on a
defective installation stand.
Be sure the installation area does not
deteriorate with age.
If the base collapses, the air conditioner could
fall with it, causing property damage, product
failure, and personal injury.
Do not let the air conditioner run for a
long time when the humidity is very high
and a door or a window is left open.
Take care to ensure that power cable
could not be pulled out or damaged during
operation.
There is risk of fire or electric shock.
Do not place anything on the power
cable.
There is risk of fire or electric shock.
Do not plug or unplug the power
supply plug during operation.
There is risk of fire or electric shock.
Do not touch (operation) the product
with wet hands.
Do not place a heater or other
appliance near the power cable.
There is risk of fire and electric shock.
Do not allow water to run into
electrical parts.
It may cause fire, failure of the product, or
electric shock.
Do not store or use flammable gas or
combustible near the product.
There is risk of fire or failure of product.
Do not use the product in a tightly
closed space for a long time.
Oxygen deficiency could occur.
When flammable gas leaks, turn off
the gas and open a window for ventilation
before turn the product on.
If strange sounds or smoke comes
2
from product, turn the breaker off or
disconnect the power supply cable.
There is risk of electric shock or fire.
Stop operation and close the window
in storm or hurricane. If possible, remove
the product from the window before the
hurricane arrives.
There is risk of property damage, failure of
product, or electric shock.
Do not open the inlet grill of the
product during operation. (Do not touch the
electrostatic filter, if the unit is so equipped.)
There is risk of physical injury, electric shock,
or product failure.
When the product is soaked, contact
an authorized service center.
There is risk of fire or electric shock.
Be caution that water could not enter
the product.
There is risk of fire, electric shock, or product
damage.
Ventilate the product from time to
time when operating it together with a stove
etc.
There is risk of fire or electric shock.
Turn the main power off when
cleaning or maintaining the product.
There is risk of electric shock.
When the product is not be used for a
long time, disconnect the power supply plug
or turn off the breaker.
There is risk of product damage or failure, or
unintended operation.
Take care to ensure that nobody
could step on or fall onto the outdoor unit.
This could result in personal injury and
product damage.
CAUTION
Always check for gas (refrigerant)
leakage after installation or repair of
product.
Low refrigerant levels may cause failure of
product.
Install the drain hose to ensure that
water is drained away properly.
A bad connection may cause water leakage.
Keep level even when installing the
product.
It can avoid vibration of water leakage.
Do not install the product where the
noise or hot air from the outdoor unit could
damage the neighborhoods.
It may cause a problem for your neighbors.
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.
It may cause corrosion on the product.
Corrosion, particularly on the condenser and
evaporator fins, could cause product
malfunction or inefficient operation.
Operational
Do not expose the skin directly to
cool air for long 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.
There is risk of damage or loss of property.
Do not block the inlet or outlet of air
flow.
Use a soft cloth to clean. Do not use
harsh detergents, solvents, etc.
There is risk of fire, electric shock, or damage
to the plastic parts of the product.
Do not touch the metal parts of the
product when removing the air filter. They
are very sharp.
Do not step on or put anything on the
product. (outdoor units)
Always insert the filter securely.
Clean the filter every two weeks or more
often if necessary.
A dirty filter reduces the efficiency of the air
conditioner and could cause product
malfunction or damage.
Do not insert hands or other objects
3
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.
Be careful and avoid personal injury.
Replace the all batteries in the remote
control with new ones of the same type. Do
not mix old and new batteries or different
types of batteries.
There is risk of fire or explosion.
Do not recharge or disassemble the
batteries. Do not dispose of batteries in a
fire.
They may burn of explode.
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.
4
2 Information servicing
1.Checks to the area
Prior to beginning work on systems containing
flammable refrigerants, safety checks are
necessary to ensure that the risk of ignition is
minimised. For repair to the refrigerating
system, the following precautions shall be
complied with prior to conducting work on the
system.
2. Work procedure
Work shall be undertaken under a controlled
procedure so as to minimise the risk of a
flammable gas or vapour being present while
the work is being performed.
3. General work area
All maintenance staff and others working in the
local area shall be instructed on the nature
of work being carried out. Work in confined
spaces shall be avoided. The area around the
work space shall be sectioned off. Ensure that
the conditions within the area have been
made safe by control of flammable material.
4. Checking for presence of refrigerant
The area shall be checked with an appropriate
refrigerant detector prior to and during work,
to ensure the technician is aware of potentially
flammable atmospheres. Ensure that the
leak detection equipment being used is suitable
for use with flammable refrigerants, i.e. no
sparking, adequately sealed or intrinsically
safe.
5. Presence of fire extinguisher
If any hot work is to be conducted on the
refrigeration equipment or any associated parts,
appropriate fire extinguishing equipment shall
be available to hand. Have a dry powder or
CO2 fire extinguisher adjacent to the charging
area.
6. No ignition sources
No person carrying out work in relation to a
refrigeration system which involves exposing
any pipe work that contains or has contained
flammable refrigerant shall use any sources of
ignition in such a manner that it may lead to the
risk of fire or explosion. All possible ignition
sources, including cigarette smoking, should be
kept sufficiently far away from the site of
installation, repairing, removing and disposal,
during which flammable refrigerant can
possibly be released to the surrounding space.
Prior to work taking place, the area around
the equipment is to be surveyed to make sure
that there are no flammable hazards or ignition
risks.NO SMOKING signs shall be displayed.
7. Ventilated area
Ensure that the area is in the open or that it is
adequately ventilated before breaking into the
system or conducting any hot work. A degree of
ventilation shall continue during the period
that the work is carried out. The ventilation
should safely disperse any released refrigerant
and preferably expel it externally into the
atmosphere.
8. Checks to the refrigeration equipment
Where electrical components are being
changed, they shall be fit for the purpose and to
the correct specification. At all times the
manufacturer's maintenance and service
guidelines shall be followed. If in doubt consult
the manufacturer's technical department for
assistance. The following checks shall be
applied to installations using flammable
refrigerants:
the charge size is in accordance with the
room size within which the refrigerant
containing parts are installed;
the ventilation machinery and outlets are
operating adequately and are not obstructed;
if an indirect refrigerating circuit is being
used, the secondary circuit shall be checked
for the presence of refrigerant; marking to the
equipment continues to be visible and legible.
markings and signs that are illegible shall be
corrected;
refrigeration pipe or components are
installed in a position where they are unlikely to
be exposed to any substance which may
corrode refrigerant containing components,
unless the components are constructed of
5
materials which are inherently resistant to being
corroded or are suitably protected against being
so corroded.
9. Checks to electrical devices
Repair and maintenance to electrical
components shall include initial safety checks
and component inspection procedures. If a fault
exists that could compromise safety, then no
electrical supply shall be connected to the
circuit until it is satisfactorily dealt with. If the
fault cannot be corrected immediately but it is
necessary to continue operation, an adequate
temporary solution shall be used. This shall be
reported to the owner of the equipment so all
parties are advised. Initial safety checks shall
include:
that capacitors are discharged: this shall be
done in a safe manner to avoid possibility of
sparking;
that there no live electrical components and
wiring are exposed while charging, recovering
or purging the system;
that there is continuity of earth bonding.
10. Repairs to sealed components
10.1 During repairs to sealed components, all
electrical supplies shall be disconnected from
the equipment being worked upon prior to any
removal of sealed covers, etc. If it is absolutely
necessary to have an electrical supply to
equipment during servicing, then a permanently
operating form of leak detection shall be
located at the most critical point to warn of a
potentially hazardous situation.
10.2 Particular attention shall be paid to the
following to ensure that by working on electrical
components, the casing is not altered in such a
way that the level of protection is affected. This
shall include damage to cables, excessive
number of connections, terminals not made to
original specification, damage to seals,
incorrect fitting of glands, etc.
Ensure that apparatus is mounted securely.
Ensure that seals or sealing materials have
not degraded such that they no longer serve
the purpose of preventing the ingress of
flammable atmospheres. Replacement parts
shall be in accordance with the manufacturer's
specifications.
NOTE: The use of silicon sealant may inhibit
the effectiveness of some types of leak
detection equipment. Intrinsically safe
components do not have to be isolated prior to
working on them.
11. Repair to intrinsically safe components
Do not apply any permanent inductive or
capacitance loads to the circuit without
ensuring that this will not exceed the
permissible voltage and current permitted for
the equipment in use. Intrinsically safe
components are the only types that can be
worked on while live in the presence of a
flammable atmosphere. The test apparatus
shall be at the correct rating.
Replace components only with parts specified
by the manufacturer. Other parts may result
in the ignition of refrigerant in the atmosphere
from a leak.
12. Cabling
Check that cabling will not be subject to wear,
corrosion, excessive pressure, vibration, sharp
edges or any other adverse environmental
effects. The check shall also take into account
the effects of aging or continual vibration from
sources such as compressors or fans.
13. Detection of flammable refrigerants
Under no circumstances shall potential sources
of ignition be used in the searching for or
detection of refrigerant leaks. A halide torch (or
any other detector using a naked flame)
shall not be used.
14. Leak detection methods
The following leak detection methods are
deemed acceptable for systems containing
flammable refrigerants. Electronic leak
detectors shall be used to detect flammable
refrigerants, but the sensitivity may not be
adequate, or may need re-calibration.
(Detection equipment shall be calibrated in a
refrigerant-free area.) Ensure that the detector
is not a potential source of ignition and is
6
suitable for the refrigerant used. Leak detection
equipment shall be set at a percentage of the
LFL of the refrigerant and shall be calibrated to
the refrigerant employed and the appropriate
percentage of gas (25 % maximum) is
confirmed. Leak detection fluids are suitable for
use with most refrigerants but the use of
detergents containing chlorine shall be avoided
as the chlorine may react with the refrigerant
and corrode the copper pipe-work.
If a leak is suspected, all naked flames shall
be removed or extinguished.
If a leakage of refrigerant is found which
requires brazing, all of the refrigerant shall be
recovered from the system, or isolated (by
means of shut off valves) in a part of the
system
remote from the leak. Oxygen free nitrogen
(OFN) shall then be purged through the
system both before and during the brazing
process.
15. Removal and evacuation
When breaking into the refrigerant circuit to
make repairs or for any other purpose
conventional procedures shall be used.
However, it is important that best practice is
followed since flammability is a consideration.
The following procedure shall be adhered to:
remove refrigerant;
purge the circuit with inert gas;
evacuate;
purge again with inert gas;
open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into
the correct recovery cylinders. The system
shall be flushed with OFN to render the
unit safe. This process may need to be
repeated several times. Compressed air or
oxygen shall not be used for this task. Flushing
shall be achieved by breaking the vacuum in
the system with OFN and continuing to fill until
the working pressure is achieved, then venting
to atmosphere, and finally pulling down to a
vacuum. This process shall be repeated until no
refrigerant is within the system. When the final
OFN charge is used, the system shall be
vented down to atmospheric pressure to enable
work to take place. This operation is absolutely
vital if brazing operations on the pipe-work are
to take place.
Ensure that the outlet for the vacuum pump is
not close to any ignition sources and there is
ventilation available.
16. Charging procedures
In addition to conventional charging procedures,
the following requirements shall be followed:
Ensure that contamination of different
refrigerants does not occur when using
charging equipment. Hoses or lines shall be as
short as possible to minimize the amount of
refrigerant contained in them.
Cylinders shall be kept upright.
Ensure that the refrigeration system is
earthed prior to charging the system with
refrigerant.
Label the system when charging is complete
(if not already).
Extreme care shall be taken not to overfill
the refrigeration system.
Prior to recharging the system it shall be
pressure tested with OFN. The system shall be
leak tested on completion of charging but prior
to commissioning. A follow up leak test shall be
carried out prior to leaving the site.
17. Decommissioning
Before carrying out this procedure, it is
essential that the technician is completely
familiar with the equipment and all its detail. It is
recommended good practice that all
refrigerants are recovered safely. Prior to the
task being carried out, an oil and refrigerant
sample shall be taken.
In case analysis is required prior to re-use of
reclaimed refrigerant. It is essential that
electrical power is available before the task is
commenced.
a) Become familiar with the equipment and its
operation.
b) Isolate system electrically.
c) Before attempting the procedure ensure that:
7
mechanical handling equipment is available,
if required, for handling refrigerant cylinders;
all personal protective equipment is
available and being used correctly;
the recovery process is supervised at all
times by a competent person;
recovery equipment and cylinders conform
to the appropriate standards.
d) Pump down refrigerant system, if possible.
e) If a vacuum is not possible, make a manifold
so that refrigerant can be removed from various
parts of the system.
f) Make sure that cylinder is situated on the
scales before recovery takes place.
g) Start the recovery machine and operate in
accordance with manufacturer's instructions.
h) Do not overfill cylinders. (No more than 80 %
volume liquid charge).
i) Do not exceed the maximum working
pressure of the cylinder, even temporarily.
j) When the cylinders have been filled correctly
and the process completed, make sure that
the cylinders and the equipment are removed
from site promptly and all isolation valves on
the equipment are closed off.
k) Recovered refrigerant shall not be charged
into another refrigeration system unless it has
been cleaned and checked.
18. Labelling
Equipment shall be labelled stating that it has
been de-commissioned and emptied of
refrigerant. The label shall be dated and signed.
Ensure that there are labels on the equipment
stating the equipment contains flammable
refrigerant.
19. Recovery
When removing refrigerant from a system,
either for servicing or decommissioning, it is
recommended good practice that all
refrigerants are removed safely.
When transferring refrigerant into cylinders,
ensure that only appropriate refrigerant
recovery cylinders are employed. Ensure that
the correct numbers of cylinders for holding the
total system charge are available. All cylinders
to be used are designated for the recovered
refrigerant and labelled for that refrigerant (i.e.
special cylinders for the recovery of refrigerant).
Cylinders shall be complete with pressure relief
valve and associated shut-off valves in good
working order.
Empty recovery cylinders are evacuated
and, if possible, cooled before recovery occurs.
The recovery equipment shall be in good
working order with a set of instructions
concerning the equipment that is at hand and
shall be suitable for the recovery of flammable
refrigerants. In addition, a set of calibrated
weighing scales shall be available and in good
working order.
Hoses shall be complete with leak-free
disconnect couplings and in good condition.
Before using the recovery machine, check that
it is in satisfactory working order, has been
properly maintained and that any associated
electrical components are sealed to prevent
ignition in the event of a refrigerant release.
Consult manufacturer if in doubt.
The recovered refrigerant shall be returned
to the refrigerant supplier in the correct
recovery cylinder, and the relevant Waste
Transfer Note arranged. Do not mix refrigerants
in recovery units and especially not in cylinders.
If compressors or compressor oils are to be
removed, ensure that they have been
evacuated to an acceptable level to make
certain that flammable refrigerant does not
remain within the lubricant. The evacuation
process shall be carried out prior to returning
the compressor to the suppliers. Only electric
heating to the compressor body shall be
employed to accelerate this process. When oil
is drained from a system, it shall be carried
out safely.
8
3. Model List
Model Names of Indoor/Outdoor Units
3D inverter
Capacity Indoor units Outdoor units
9k MSMTAU-09HRFN8-QRD6GW MOB01-09HFN8-QRD6GW
12k MSMTAU-12HRFN8-QRD6GW MOB01-12HFN8-QRD6GW
9
4. Dimension
4.1 Indoor Unit
W
H
Model W D H
MSMTAU-09HRFN8-QRD6GW 886 188 315
MSMTAU-12HRFN8-QRD6GW 886 188 315
10
For MSMTAU-09HRFN8-QRD6GW, MSMTAU-12HRFN8-QRD6GW
11
4.2 Outdoor Unit
More than 30cm
More than 60cm
More than 200cm
More than 30cm
More than 60cm
(Service space
︶
F
e
n
c
e
o
r
ob
s
t
ac
l
es
12
For MOB01-09HFN8-QRD6GW, MOB01-12HFN8-QRD6GW
800 W
514 W1
554
60
85.5
340
12.0
311
815 W3
365
333 D
70 W2
H
H1
H2
D1
D2
D3
62 B1
106 B2
20 A1
R
2
0
R
6
61.6 A2
13
5. Refrigerant Cycle Diagram
LIQUID SIDE
GAS SIDE
HEAT
EXCHANGE
(EVAPORATOR)
HEAT
EXCHANGE
(CONDENSER)
COMPRESSOR
2-WAY VALVE
3-WAY VALVE
4-WAY VALVE
COOLING
HEATING
T2 Evaporator
temp. sensor
T1 Room temp.
sensor
ACCUMULATOR
INDOOR OUTDOOR
CHECK VALVE
(Heating Model only)
CAPILIARY TUBE
14
6 Installation Details
6.1 Wrench torque sheet for installation
Outside diameter Torque Additional tightening torque
mm inch N.cm N.cm
Ф6.35 1/4 1500(153kgf.cm) 1600(163kgf.cm)
Ф9.52 3/8 2500(255kgf.cm) 2600(265kgf.cm)
Ф12.7 1/2 3500(357kgf.cm) 3600(367kgf.cm)
Ф15.9 5/8 4500(459kgf.cm) 4700(479kgf.cm)
Ф19 3/4 6500(663kgf.cm) 6700(683kgf.cm)
6.2 Connecting the cables
The power cord of connect should be selected according to the following specifications sheet.
Rated current of appliance Nominal cross-sectional area (mm²)
>3 and ≤6 0.75
>6 and ≤10 1
>10 and ≤16 1.5
>16 and ≤25 2.5
The cable size and the current of the fuse or switch are determined by the maximum current indicated
on the nameplate which located on the side panel of the unit. Please refer to the nameplate before
selecting the cable, fuse and switch.
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