Mitsubishi Electric MXZ-8A140VA1 Operating manual

TECHNICAL & SERVICE MANUAL
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
CONTENTS
1. TECHNICAL CHANGES................................... 2
2. SAFETY PRECAUTION.................................... 3
3. OVERVIEW OF UNITS......................................6
4. SPECIFICATIONS........................................... 14
5. DATA................................................................16
6. OUTLINES AND DIMENSIONS...................... 19
7. WIRING DIAGRAM......................................... 21
8. NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION.... 25
9. TROUBLESHOOTING.................................... 27
10. ELECTRICAL WIRING....................................75
11. WIRING SPECIFICATIONS.............................76
12. SYSTEM CONTROL........................................ 77
13. REFRIGERANT PIPING TASK....................... 79
14. DISASSEMBLY PROCEDURE....................... 82
15. PARTS LIST.................................................... 88
16. RoHS PARTS LIST......................................... 95
17. OPTIONAL PARTS.......................... Back cover
INDOOR UNITS COMBINATION SHEETS
OUTDOOR UNIT
BRANCH BOX
No. OC316
REVISED EDITION-E
[Model name] [Service Ref.]
<Outdoor unit>
MXZ-8A140VA MXZ-8A140VA
MXZ-8A140VA1
MXZ-8A140VA2
MXZ-8A140VA3
<Branch box>
PAC-AK50BC PAC-AK50BC
PAC-AK30BC PAC-AK30BC
PAC-AK51BC PAC-AK51BC
PAC-AK31BC PAC-AK31BC
(Indispensable optional parts for MXZ-8A140VA)
Model name
indication
HFC
utilized
R410A
Revision:
•
PAC-AK51/31BC are added
in REVISED EDITION-E.
• Some descriptions have
been modified.
• Please void OC316
REVISED EDITION-D.
April 2010
NOTE:
• This service manual
describes technical data of
outdoor unit and branch box.
As for indoor units, refer to
its service manual.
• RoHS compliant products
have <G> mark on the
spec name plate.
• For servicing RoHS com-
pliant products, refer to the
RoHS PARTS LIST.

2
1 TECHNICAL CHANGES
MXZ-8A140VA2MXZ-8A140VA3
The parts below have been changed.
• THERMISTOR (DISCHARGE/TH4) (Connector change)
• CONTROLLER CIRCUIT BOARD (C.B)
• NOISE FILTER CIRCUIT BOARD (N.F.)
• ACTIVE FILTER MODULE (ACTM)
• RELAY (52C), RESITOR (RS) (including N.F.)
MXZ-8A140VA1MXZ-8A140VA2
The parts below have been changed.
• FOUR-WAY VALVE AND COIL (21S4)
• CONTROLLER CIRCUIT BOARD (C.B.)
• FAN MOTOR (MF1, MF2)
• SOLENOID VALVE AND COIL (SV2)
MXZ-8A140VA MXZ-8A140VA1
The parts below have been changed.
• POWER CIRCUIT BOARD (P.B.)
• NOISE FILTER CIRCUIT BOARD (N.F.)
• THERMISTOR (OUTDOOR/TH7)
(Length change)

3
2 SAFETY PRECAUTION
Cautions for units utilizing refrigerant R410A
2-1. ALWAYS OBSERVE FOR SAFETY
Use new refrigerant pipes.
Charge refrigerant from liquid phase of gas
cylinder.
If the refrigerant is charged from gas phase, composition
change may occur in refrigerant and the efficiency will be
lowered.
Do not use refrigerant other than R410A.
If other refrigerant (R22 etc.) is used, chlorine in refrige-
rant can cause deterioration of refrigerant oil etc.
Use a vacuum pump with a reverse flow check
valve.
Vacuum pump oil may flow back into refrigerant cycle and
that can cause deterioration of refrigerant oil etc.
Use the following tools specifically designed for
use with R410A refrigerant.
The following tools are necessary to use R410A refrigerant.
Handle tools with care.
If dirt, dust or moisture enters into refrigerant cycle, that can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refrigera-
nt will change and the efficiency will be lowered.
Flare tool
Electronic refrigerant
charging scale
Vacuum pump adaptor
Size adjustment gauge
Gauge manifold
Torque wrench
Gas leak detector
Charge hose
Tools for R410A
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil etc.
If dirt, dust or moisture enters into refrigerant cycle, that can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
If large amount of mineral oil enters, that can cause deterio-
ration of refrigerant oil etc.
Store the piping to be used indoors during
installation, and both ends of the piping sealed
until just before brazing. (Leave elbow joints, etc.
in their packaging.)
Make sure that the inside and outside of refrige-
rant piping is clean and it has no contaminants
such as sulfur, oxides, dirt, shaving particles, etc,
which are hazard to refrigerant cycle.
In addition, use pipes with specified thickness.
The refrigerant oil applied to flare and flange
connections must be ester oil, ether oil or
alkylbenzene oil in a smalll amount.
Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.
2-2. CAUTIONS RELATED TO NEW REFRIGERANT
Before obtaining access to terminal, all supply
circuit must be disconnected.

4
Gravimeter
Unit
[3] Service tools
(1) Use the below service tools as exclusive tools for R410A refrigerant.
[2] Additional refrigerant charge
When charging directly from cylinder
· Check that cylinder for R410A on the market is syphon type.
· Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.)
[1] Cautions for service
(1) Perform service after recovering the refrigerant left in unit completely.
(2) Do not release refrigerant in the air.
(3) After completing service, charge the cycle with specified amount of refrigerant.
(4) When performing service, install a filter drier simultaneously.
Be sure to use a filter drier for new refrigerant.
No. Tool name Specifications
1Gauge manifold
· Only for R410A
· Use the existing fitting specifications. (UNF1/2)
· Use high-tension side pressure of 5.3MPa·G or over.
2Charge hose · Only for R410A
· Use pressure performance of 5.09MPa·G or over.
3Electronic scale
4Gas leak detector · Use the detector for R134a, R407C or R410A.
5Adaptor for reverse flow check · Attach on vacuum pump.
6Refrigerant charge base
7Refrigerant cylinder · Only for R410A · Top of cylinder (Pink)
· Cylinder with syphon
8Refrigerant recovery equipment

5
(2) Cautions for refrigerant piping work
New refrigerant R410A is adopted for replacement inverter series. Although the refrigerant piping work for R410A is same
as for R22, exclusive tools are necessary so as not to mix with different kind of refrigerant. Furthermore as the working
pressure of R410A is 1.6 times higher than that of R22, their sizes of flared sections and flare nuts are different.
1Thickness of pipes
Because the working pressure of R410A is higher compared to R22, be sure to use refrigerant piping with thickness
shown below. (Never use pipes of 0.7 mm or below.)
2Dimensions of flare cutting and flare nut
The component molecules in HFC refrigerant are smaller compared to conventional refrigerants. In addition to that,
R410A is a refrigerant, which has higher risk of leakage because of its working pressure higher than that of other refriger-
ants. Therefore, to enhance airtightness and intensity, flare cutting dimension of copper pipe for R410A has been speci-
fied separately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A also
has partly been changed to increase intensity as shown below. Set copper pipe correctly referring to copper pipe flaring
dimensions for R410A below. For 1/2” and 5/8”, the dimension B changes.
Use torque wrench corresponding to each dimension.
3Tools for R410A (The following table shows whether conventional tools can be used or not.)
1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
0.8
0.8
0.8
1.0
—
0.8
0.8
0.8
1.0
1.0
Nominal
dimensions(inch)
Diagram below: Piping diameter and thickness
Outside
diameter (mm)
Thickness (mm)
R410A R22
1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
9.1
13.2
16.6
19.7
—
9.0
13.0
16.2
19.4
23.3
Nominal
dimensions(inch)
Flare cutting dimensions
Outside
diameter
Dimension A ( )
+0
-0.4
(mm)
R410A R22
1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
17.0
22.0
26.0
29.0
—
17.0
22.0
24.0
27.0
36.0
Nominal
dimensions(inch)
Flare nut dimensions
Outside
diameter
Dimension B
(mm)
R410A R22
Gauge manifold
Charge hose
Gas leak detector
Refrigerant recovery equipment
Refrigerant cylinder
Applied oil
Safety charger
Charge valve
Vacuum pump
Flare tool
Bender
Pipe cutter
Welder and nitrogen gas cylinder
Refrigerant charging scale
Vacuum gauge or thermis-
tor vacuum gauge and
vacuum valve
Charging cylinder
Air purge, refrigerant charge
and operation check
Gas leak check
Refrigerant recovery
Refrigerant charge
Apply to flared section
Prevent compressor malfunction
when charging refrigerant by
spraying liquid refrigerant
Prevent gas from blowing out
when detaching charge hose
Vacuum drying and air
purge
Flaring work of piping
Bend the pipes
Cut the pipes
Weld the pipes
Refrigerant charge
Check the degree of vacuum. (Vacuum
valve prevents back flow of oil and refri-
gerant to thermistor vacuum gauge)
Refrigerant charge
Tool exclusive for R410A
Tool exclusive for R410A
Tool for HFC refrigerant
Tool exclusive for R410A
Tool exclusive for R410A
Ester oil and alkylbenzene
oil (minimum amount)
Tool exclusive for R410A
Tool exclusive for R410A
Tools for other refrigerants can
be used if equipped with adop-
ter for reverse flow check
Tools for other refrigerants
can be used by adjusting
flaring dimension
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants
can be used
Tool exclusive for R410A
Tools and materials Use R410A tools Can R22 tools be used?
(Usable if equipped
with adopter for rever-
se flow)
(Usable by adjusting
flaring dimension)
Can R407C tools be used?
Ester oil:
Alkylbenzene oil: minimum amount
(Usable if equipped
with adopter for rever-
se flow)
(Usable by adjusting
flaring dimension)
: Prepare a new tool. (Use the new tool as the tool exclusive for R410A.)
: Tools for other refrigerants can be used under certain conditions.
: Tools for other refrigerants can be used.
Dimension A
Dimension B

6
3 OVERVIEW OF UNITS
3-1. CONSTRUCTION OF SYSTEM
5HP
Rated capacity (kW)
(Cooling/Heating) 14.0/16.0
MXZ-8A140VA/ MXZ-8A140VA
1 / MXZ-8A140VA 2 / MXZ-8A140VA 3
R410A
Indoor unit
that can be
connected
Branch box
that can be
connected
Capacity
Number of units
Total system wide capacity
Type 15 ~ Type 80
2 ~ 8 units
1 ~ 2 units
21 ~ 132 % of outdoor unit capacity (3.0 kW ~ 18.5 kW)
Number of units
Outdoor unit
Ceiling
concealed
4-way
ceiling cassette
Wall
mounted
Model type Model name
Deluxe
Standard
Compact
Low static pressure
Middle static pressure
High static pressure
2 by 2 type
Standard
MSZ-FA25/35VA
MSZ-FB25/35/50VA(H)
MSZ-FD25/35/50VA
MSZ-GA22/25/35/50/60/71/80VA
MSZ-GB50VA
MSZ-GC22/25/35VA
MSZ-GC22/25/35/50/60/71NA
MSZ-GE22/25/35/42/50/60/71VA/NA
MSZ-SF15/20VA
SEZ-KA/KC25/35/50/60/71VA
SEZ-KD25/35/50/60/71VA(L)
PEAD-RP50/60/71EA.UK
PEAD-RP60/71GA.UK
PEAD-RP50/60/71JA(L).UK
PEA-RP71EA
MCFZ-GA35/50/60VA
SLZ-KA25/35/50VA(L)
PLA-RP35/50/60/71AA(.UK)/BA(.UK)
PLA-RP71BA2.UK
MFZ-KA25/35/50VA
MLZ-KA25/35/50VA
Floor standing
Capacity class (kW)
2.2 2.5 3.5 5.0 6.0 7.1 8.0
Connectable indoor unit lineup (Heat pump inverter type)
<NOTE> The lineup of a connectable indoor unit depends on a district/areas/country.
Branch box PAC-AK50BC
PAC-AK51BC
5 branches
(MAX. 5 units)
PAC-AK30BC
PAC-AK31BC
3 branches
(MAX. 3 units)
Number of branches
Indoor unit that
can be connected
( )
+Max. 2 branch boxes can be connected to 1 outdoor unit.
+According to the connection method, you can choose the favorite one.
2- branch pipe (joint) : Optional parts
In case of using 1- branch box
In case of using 2- branch boxes
No need
Model name Connection method
flare
brazing
MSDD-50AR-E
MSDD-50BR-E
Option Optional accessories of indoor units and outdoor units are available.
CAUTION : The indoor unit which rated capability exceeds
8.0kW (80 type) can NOT be connected.
2.0
1.5 4.2
1-way ceiling cassette

7
Indoor unit (Ceiling concealed type)
Indoor unit
(Wall mounted type)
Outdoor unit Branch Box
3-2. SYSTEM OUTLINE
The additional connection of the Branch Box together with employment of the compact trunk-looking outdoor unit can
successfully realizes a long distance piping for big houses. Equipped with a microcomputer, the Branch Box can trans-
late the transmission signal of indoor units to achieve the optimum control.
3-2-1. System example
3-2-2. Method for identifying
■Outdoor unit
M X Z - 8 A 140 V A
Model type
Power supply
V: Single phase 220/230/240V 50Hz
220V 60Hz
Multi type heat pump
inverter outdoor unit
Indicates equivalent to rated cooling capacity.
(0.1kW)
Number of connectable indoor units (MAX.)
Control and refrigerant
A : New A control and R410A
Branch box (Controller)
Number of branches
5 : 5 branches
3 : 3 branches
Model type
Symbol of factory
Applicable refrigerant
A : R410A
P A C - A K 5 0 BC
(Indispensable)
Optional parts
■Branch box

8
3-3. TYPICAL COMBINATION EXAMPLE
Branch box is located INSIDE of condominium
Branch box
(Inside)
Installing branch box indoors
Only 1 piping is required between the outdoor and
indoor offering a fine external view.
Branch box (5 branch type)
Outdoor unit
SEZ-60 MSZ-35 MSZ-35 MSZ-25 MSZ-25
Living Dining Bedroom (1) Bedroom (2)
Master
bedroom
■System example of 5 indoor units
■Verification
The rated capacity should be determined by observing the table below. The unit’s quantities are limited in 2 to 8 units.
For the next step, make sure that the selected total rated capacity is in a range of 4.4 ~ 18.5 kW.
The total indoor unit capacity should be within the outdoor units. (= 14.0 kW is preferred).
Combination of excessive indoor units and an outdoor unit may reduce the capacity of each indoor unit.
The rated indoor capacity is as the table below.
Example:
Total rated capacity
18.0 18.5kW
MSZ-25 =2.5
+
+
+
+
SEZ-60 = 6.0
MSZ-35 = 3.5
MSZ-35 = 3.5
MSZ-25 = 2.5
Indoor unit type (capacity class) 15 20 22 25 35 42 50 60 71 80
Rated capacity (cooling) (kW) 1.5 2.0 2.2 2.5 3.5 4.2 5.0 6.0 7.1 8.0

9
3-4. INSTALLATION
3-4-1. Outdoor unit installation location
For best performance, select proper position.
●Avoid places where combustible gas may be generated or leak.
●Avoid direct sunlight or other sources of heat.
●Install sunshade to protect the outdoor unit if direct sunlight hits the unit.
●Install the outdoor unit with enough distance between neighbours as operation noise may disturb the neighbours.
●Avoid the position that the unit is covered by snow or snow blows directly against the air outlet. The snow block or blow will
reduce the airflow of the outdoor unit.
In the areas of heavy snow, special countermeasures must be taken at installation to protect the outdoor unit from malfunc-
tion caused by snow.
●Select a location permitting easy wiring and pipe access to the power source and indoor unit.
●Drain water must be drained freely during operation. Check for draining.
3-4-2. Ventilation and service space
(1) Windy location installation
When installing the outdoor unit on a rooftop or other location unprotected from the wind, situate the air outlet of the unit so
that it is not directly exposed to strong winds. Strong wind entering the air outlet may impede the normal airflow and a mal-
function may result.
The following shows 3 examples of precautions against strong winds.
●Face the air outlet towards the nearest available wall about 50 cm away from the wall. (Fig. 2-1)
●Install an optional air guide if the unit is installed in a location where strong winds from a typhoon, etc. may directly enter
the air outlet. (Fig. 2-2)
AAir guide
●Position the unit so that the air outlet blows perpendicularly to the seasonal wind direction, if possible. (Fig. 2-3)
BWind direction
Fig. 2-1 
Fig. 2-2

Fig. 2-3

10
(2) When installing a single outdoor unit
Minimum dimensions are as follows, except for Max., meaning Maximum dimensions, indicated.
Refer to the figures for each case.
●Obstacles at rear only (Fig. 2-4)
●Obstacles at rear and above only (Fig. 2-5)
· Do not install the optional air outlet guides for upward airflow.
●Obstacles at rear and sides only (Fig. 2-6)
●Obstacles at front only (Fig. 2-7)
wWhen using an optional air outlet guide, the clearance is 500 mm or more.
●Obstacles at front and rear only (Fig. 2-8)
wWhen using an optional air outlet guide, the clearance is 500 mm or more.
●Obstacles at rear, sides, and above only (Fig. 2-9)
· Do not install the optional air outlet guides for upward airflow.
150
250
25
0
1500
500
Max. 500
1000
200
300
200
Fig. 2-4
Fig. 2-8Fig. 2-7
Fig. 2-5 Fig. 2-6
Fig. 2-9
unit : mm
300
1000
Max. 500
150
1000