Mitsubishi Electric MXZ-8B48NA Operating manual

TECHNICAL & SERVICE MANUAL
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
CONTENTS
1. TECHNICAL CHANGE.................................... 2
2. SAFETY PRECAUTION....................................2
3. OVERVIEW OF UNITS......................................5
4. SPECIFICATIONS.............................................9
5. DATA................................................................ 11
6. OUTLINES AND DIMENSIONS......................34
7. WIRING DIAGRAM.........................................36
8.
NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION.... 38
9. TROUBLESHOOTING.................................... 39
10. PRECAUTIONS AGAINST REFRIGERANT LEAKAGE
..... 79
11. DISASSEMBLY PROCEDURE....................... 81
OUTDOOR UNIT
BRANCH BOX
No. OCH468
REVISED EDITION-C
[Service Ref.]
MXZ-8B48NA
MXZ-8B48NAR1
PAC-AKA51BC
PAC-AKA31BC
Model name
indication
HFC
utilized
R410A
November 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.
[Model name]
<Outdoor unit>
MXZ-8B48NA
<Branch box>
PAC-AKA51BC
PAC-AKA31BC
(Indispensable optional parts
for MXZ-8B48NA)
PARTS CATALOG (OCB468)
• Please void OCH468
REVISED EDITION-B.
Revision:
• Switch setting on page 68
has been modified in
REVISED EDITION-C.
• Some descriptions have
been modified.

2
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.
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.
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.)
The refrigerant oil applied to flare and flange
connections must be ester oil, ether oil or
alkylbenzene oil in a small 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.
2 SAFETY PRECAUTION
1TECHNICAL CHANGE
MXZ-8B48NA MXZ-8B48NAR1
• THERMISTOR has been changed. (Discharge thermistor ĺCompressor thermistor)

3
Gravimeter
Unit
[3] Service tools
(1) Use the below service tools as exclusive tools for R410A 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
[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.

4
2-3. 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 [7/256 inch] 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 its working pressure is higher than that of other
refrigerants. Therefore, to enhance airtightness and intensity, flare cutting dimension of copper pipe for R410A has
been specified 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 cop-
per pipe flaring dimensions for R410A below. For 1/2 and 5/8 inch, 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 [1/32]
0.8 [1/32]
0.8 [1/32]
1.0 [5/128]
—
0.8 [1/32]
0.8 [1/32]
0.8 [1/32]
1.0 [5/128]
1.0 [5/128]
Nominal
dimensions[inch]
Diagram below: Piping diameter and thickness
Outside
diameter (mm)
Thickness (mm) [inch]
R410A R22
1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
9.1 [11/32-23/64]
13.2 [1/2-33/64]
16.6 [41/64-21/32]
19.7 [49/64-25/32]
—
9.0
13.0
16.2
19.4
23.3
Nominal
dimensions[inch]
Flare cutting dimensions
Outside
diameter Dimension A ( )
+0
-0.4
(mm) [inch]
R410A R22 1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
17.0 [43/64]
22.0 [7/8]
26.0 [1-3/64]
29.0 [1-9/64]
—
17.0
22.0
24.0
27.0
36.0
Nominal
dimensions[inch]
Flare nut dimensions Outside
diameter[inch] Dimension B
(mm) [inch]
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, ether 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, ether 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

5
3 OVERVIEW OF UNITS
3-1. CONSTRUCTION OF SYSTEM
6HP
Rated capacity (kBTU/h)
(Cooling/Heating) 48/54
MXZ-8B48NA, MXZ-8B48NAR1
R410A
Indoor unit
that can be
connected
Branch box
that can be
connected
Capacity
Number of units
Total system wide capacity
Type 06 ~ Type 24
2 ~ 8 units
1 ~ 2 units
22.2 ~ 130 % of outdoor unit MAX. Cooling capacity (12 kBTU/h ~ 70.2kBTU/h)
Number of units
Outdoor unit
Branch box PAC-AKA51BC
5 branches
(MAX. 5 units)
PAC-AKA31BC
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.
MAX. capacity (kBTU/h)
(Cooling/Heating) 54/60
Ceiling
concealed
4-way ceiling cassette
Wall
mounted
Model type Model name
Deluxe
Standard
Low static pressure
Middle static pressure
Standard
MSZ-FE09/12, MSZ-FD09/12
MSZ-GE06/09/12/15/18/24
MSZ-GA24
MSZ-A09/12/15/17/24
SEZ-KD09/12/15/18
PEAD-A24AA
PLA-A12/18/24BA
MFZ-KA09/12/18NA
Floor standing
Capacity class [kBTU/h]
06 09 12 15 18(17) 24
Connectable indoor unit lineup (Heat pump inverter type)
<NOTE> When connecting MSZ-FE18NA model, joint pipe is necessary for both liquid and gas pipes.

6
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 suc-
cessfully realizes a long distance piping for big houses. Equipped with a microcomputer, the Branch Box can translate the
transmission signal of indoor units to achieve the optimum control.
3-2-1. System example
3-2-2. Method for identifying
ŶOutdoor unit
Development No. : A, B, ···,etc.
Power supply
N: Single phase 208/230V 60Hz
Multi type heat pump
inverter outdoor unit
Indicates equivalent to rated cooling capacity.
(kBTU/h)
Number of connectable indoor units (MAX.)
Control and refrigerant
A : New A control and R410A
Service No. : 1, 2, ···,etc.
M X Z-4 88B NA
P A C-A K A 5 1 B C
(Indispensable)
Optional parts
Symbol of factory
Branch box (Controller)
Number of branches
5 : 5 branches
3 : 3 branches
Applicable refrigerant
A : R410A
Marketable area
A: America
ŶBranch box

7
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-18 MSZ-12 MSZ-12 MSZ-09 MSZ-09
Living Dining Bedroom (1) Bedroom (2)
Master
bedroom
Indoor unit type (capacity class)
Rated capacity (cooling) (kBTU/h)
06
6
09
9
12
12
15
15
24
24
18
18
ŶSystem example of 5 indoor units
ŶVerification
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 12 ~ 70.2 kBTU/h.
The total indoor unit capacity should be within the outdoor units. (=54.0 kBTU/h 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
60 70.2 kBTU/h
MSZ-09 = 9
+
+
+
+
SEZ-18 = 18
MSZ-12 = 12
MSZ-12 = 12
MSZ-09 = 9

8
3-4. SIMPLIFIED PIPING SYSTEM
Piping connection size
Liquid
Gas
W9.52 mm
(3/8 inch)
W15.88 mm
(5/8 inch)
The piping connection size differs according to the type and capacity of indoor units.
Match the piping connection size of branch box with indoor unit.
If the piping connection size of branch box does not match the piping connection size of
indoor unit, use optional different-diameter (deformed) joints to the branch box side.
(Connect deformed joint directly to the branch box side.)
AB
Flare connection employed. (No brazing!)
A
BB BBB
Branch box
ŶIn case of using 1-branch box
Flare connection employed (No brazing)
AA
A
BB BBB
2 branches pipe (joint)
: optional parts
Branch box #1
Branch box #2
ŶIn case of using 2-branch boxes
ŶInstallation procedure (2 branch pipe (joint))
Refer to the installation manuals of MSDD-50AR-E and MSDD-50BR-E.

9
4 SPECIFICATIONS
• Outdoor unit : MXZ-8B48NA/MXZ-8B48NAR1 Conversion formula: kcal/h = kW %860
Btu/h = kW %3412
CFM = m3/min %35.31
Service Ref. MXZ-8B48NA, MXZ-8B48NAR1
Standard performance
Indoor type Non-Ducted Mix Ducted
Cooling
Capacity Rated / Max (*1) Btu/h 48000 / 54000
Rated power consumption (*1) W 5780 6125 6470
EER Btu/Wh 8.30 7.84 7.42
SEER Btu/Wh 15.0 14.8 14.7
Heating
Capacity Rated / Max 47 °F (*1) Btu/Wh 54000 / 60000
Capacity 17 °F *2 Btu/Wh 36600 36550 36500
Rated power consumption 47 °F (*1) W 4820 5045 5270
COP 47 °F (*1) Btu/Wh 11.20 10.70 10.25
HSPF 4/ 5Btu/Wh 8.7 / 7.0 8.8 / 7.0 8.9 / 7.1
OUTDOOR UNIT
Connectable indoor units (Max.) 8
Max. Connectable Capacity 70200 Btu/Wh (130% of Outdoor Unit Max Capacity)
Power supply 208/230, 1, 60
Breaker Size / Max. fuse size 50A / 52A
Min. circuit ampacity 32A
Sound level (Cool/Heat) dB 54 / 55
External ¿nish Munsell 3Y 7.8/1.1
Refrigerant control Linear Expansion Valve
Compressor Hermetic
Model ANB33FDSMT
Motor output kW 2.9
Starting method Inverter
Heat exchanger Plate ¿n coil
Fan Fan (drive) × No. Propeller fan × 2
Fan motor output kW 0.086 + 0.086
AirÀow m³/min (CFM) 100 (3,530)
Dimensions
(H × W × D)
W mm (in.) 980 (37-13/32)
D mm (in.) 330+30 (13+1-3/16)
H mm (in.) 1,350 (53-5/32)
Weight kg (lbs) 126 (278)
Refrigerant R410A
Charge kg (lbs) 8.5 (18.7)
Oil / Model L (oz) 2.3 (73) / FV50S
Protection devices High pressure protection HP switch
Compressor protection Discharge thermo, Over current detection (MXZ-8B48NA)
Compressor thermo, Over current detection (MXZ-8B48NAR1)
Fan motor protection Overheating / Voltage protection
Guaranteed operation range (cool) -5 〜46 °C DB (23 ~ 115 °F DB)
(heat) -15 〜21 °C DB (5 ~ 70 °F DB)
REFRIGERANT PIPING
Total Piping length (Max.) m (ft) 115 (377)
Farthest m (ft) 70 (300)
Max. Height difference m (ft) 30 (98) (*3)
Chargeless length m (ft) 40 (131)
Piping diameter Liquid [mm (in.) [9.52 (3/8)
Gas [mm (in.) [15.88 (5/8)
Connection method Indoor side Flared
Outdoor side Flared
(*1) Rating conditions Cooling Indoor : D.B.26.7°C / W.B.19.4°C (D.B.80°F / W.B.67 °F)
Outdoor : D.B.35.0°C (95°F)
Heating Indoor : D.B.21.1°C (70°F)
Outdoor : D.B.8.3°C / W.B.6.1°C (D.B.47°F / W.B.43°F)
(*2) Conditions Heating Indoor : D.B.21.1°C (70°F)
Outdoor : D.B. - 8.3°C / W.B. - 9.4°C (D.B.17°F / W.B.15°F)
(*3) 20m (66ft) ：In case of installing outdoor unit lower than indoor unit.
Note : Refer to the service manual of indoor unit for the indoor units speci¿cations.

10
kW
A
mm (in.)
mm (in.)
mm (in.)
mm (in.)
kg (lbs)
mm (in.)
mm (in.)
mm (in.)
mm (in.)
Model name
Connectable number of indoor units
Power supply (from outdoor unit)
Input
Running current
External finish
Drain hose size (on site)
Dimensions
Weight
Piping
connection
(Flare)
Wiring
Width
Depth
Height
Branch (indoor side)
Main (outdoor side)
To indoor unit
To outdoor unit
Liquid
Gas
Liquid
Gas
MAX. 3
8.4 (19)
:6.35 (1/4) × 3 {A,B,C}
:9.52 (3/8) × 3 {A,B,C}
MAX. 5
9.6 (21)
:6.35 (1/4) × 5 {A,B,C,D,E}
:9.52 (3/8) × 4 {A,B,C,D},
:12.7 (1/2) × 1{E}
PAC-AKA51BC PAC-AKA31BC
Single phase, 208/230V, 60Hz
0.003
0.05
Galvanized sheets
O.D.20 (O.D. 3/4)
450 (17 - 3/4)
280 (11)
198 (7 - 3/4)
:9.52 (3/8)
:15.88 (5/8)
Each 3-wire, plus earth wire
3-wire, plus earth wire

• Branch box : PAC-AKA51BC PAC-AKA31BC
W The piping connection size differs according to the type and capacity of indoor units. Match the piping connection size for indoor
and branch box. If the piping connection size of branch box does not match the piping connection size of indoor units, use
optional different-diameter (deformed) joints to the branch box side. (Connect deformed joint directly to the branch box side.)