Mitsubishi Electric MXZ-SM48NAM Operating manual

TECHNICAL & SERVICE MANUAL
OUTDOOR UNIT
No. OCH789
HFC
utilized
R410A
November 2021
Note:
• This service manual
describes technical data of
the outdoor units only.
<Outdoor unit>
[Model Name]
Model name
indication
PARTS CATALOG (OCB789)
MXZ-SM36NAM
MXZ-SM48NAM
MXZ-SM60NAM
MXZ-SM36NAMHZ
MXZ-SM42NAMHZ
MXZ-SM48NAMHZ
MXZ-SM36NAM-U1
MXZ-SM48NAM-U1
MXZ-SM60NAM-U1
MXZ-SM36NAMHZ-U1
MXZ-SM42NAMHZ-U1
MXZ-SM48NAMHZ-U1
[Service Ref.]
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
CONTENTS
1. SAFETY PRECAUTION ·······················2
2. OVERVIEW OF UNITS ························ 5
3. SPECIFICATIONS ···························· 11
4. DATA·············································· 14
5. OUTLINES AND DIMENSIONS ··········· 36
6. WIRING DIAGRAM ··························· 37
7. NECESSARY CONDITIONS
FOR SYSTEM CONSTRUCTION········· 40
8. TROUBLESHOOTING ······················· 55
9. ELECTRICAL WIRING ·····················134
10. REFRIGERANT PIPING TASKS ·········140
11. DISASSEMBLY PROCEDURE ···········148

2
OCH789
Cautions for units utilizing refrigerant R410A
1-2. CAUTIONS RELATED TO NEW REFRIGERANT
1SAFETY PRECAUTION
1-1. ALWAYS OBSERVE FOR SAFETY
Before obtaining access to terminal, all supply circuit must be disconnected.
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 refrigerating
cycle.
• When the repair or the inspection of the circuit needs
to be done without turning o󰀨 the power, exercise great
caution not to touch the live parts.
•
When opening or closing the valve below freezing
temperatures, refrigerant may spurt out from the gap
between the valve stem and the valve body, resulting in
injuries.
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
o󰀨 the power-supply breaker.
• Discharge the condenser before the work involving the
electric parts.
Use new refrigerant pipes.
Avoid using thin pipes.
Use a vacuum pump with a reverse ow check
valve.
Vacuum pump oil may ow back into refrigerant cycle and
that can cause deterioration of refrigerant oil, etc.
Handle tools with care.
If dirt, dust or moisture enters into refrigerant cycle, that
can cause deterioration of refrigerant oil or malfunction of
compressor.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refrigera-
nt will change and the e󰀩ciency will be lowered.
Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a ame, poisonous gases will be released.
Use the following tools specically designed for
use with R410A refrigerant.
The following tools are necessary to use R410A
refrigerant.
Tools for R410A
Gauge manifold Flare tool
Charge hose Size adjustment gauge
Gas leak detector Vacuum pump adaptor
Torque wrench Electronic refrigerant
charging scale
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 specied thickness.
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil, etc.
Store the piping indoors, and keep both ends of
the piping sealed until just before brazing.
(Leave elbow joints, etc. in their packaging.)
If dirt, dust or moisture enters into refrigerant cycle, that
can cause deterioration of refrigerant oil or malfunction of
compressor.
Follow the instructions below to prevent abrasive
components contained in sandpaper and cutting
tools from entering the refrigerant circuit because
those components can cause failures of the
compressor and valves.
• To deburr pipes, use a reamer or other deburring tools,
not sandpaper.
• To cut pipes, use a pipe cutter, not a grinder or other tools
that use abrasive materials.
• When cutting or deburring pipes, do not allow cutting
chips or other foreign matters to enter the pipes.
• If cutting chips or other foreign matters enter pipes, wipe
them o󰀨 the inside of the pipes.

3
OCH789
2
Electronic weighing scale
Unit
[3] Service tools
Use the below service tools as exclusive tools for R410A refrigerant.
[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) If moisture or foreign matter might have entered the refrigerant piping during service, ensure to remove them.
[2] Additional refrigerant charge
When charging directly from cylinder
(1) Check that cylinder for R410A on the market is a syphon type.
(2) Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.)
No. Tool name Specifications
1Gauge manifold · Only for R410A
· Use the existing fitting specifications. (UNF1/2)
· Use high-tension side pressure of 768.7 PSIG [5.3 MPa.G] or over.
2Charge hose · Only for R410A
· Use pressure performance of 738.2 PSIG [5.09MPa.G] or over.
3Electronic weighing 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 —
Use the specied refrigerant only.
Never use any refrigerant other than that specied.
Doing so may cause a burst, an explosion, or re when
the unit is being used, serviced, or disposed of.
Correct refrigerant is specied 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.
The refrigerant oil applied to are and ange
connections must be ester oil, ether oil or
alkylbenzene oil in a small amount.
If large amount of mineral oil enters, that can cause
deterioration of refrigerant oil, etc.
Charge refrigerant from liquid phase of gas
cylinder.
If the refrigerant is charged from gas phase, composition
change may occur in refrigerant and the e󰀩ciency 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.
Do not pump down the system when a gas leak
has been detected.
The intake of air or other gases causes abnormally high
pressure in the refrigeration cycle, which may cause
explosion or injury.

4
OCH789
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 7/256 in [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 its working pressure is higher than that of other refrigerants.
Therefore, to enhance airtightness and strength, flare cutting dimension of copper pipe for R410A has been specified sepa-
rately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A also has partly
been changed to increase strength as shown below. Set copper pipe correctly referring to copper pipe flaring dimensions for
R410A below. For 1/2 and 5/8 inch pipes, 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
1/32 [0.8]
1/32 [0.8]
1/32 [0.8]
5/128 [1.0]
5/128 [1.0]*
1/32 [0.8]
1/32 [0.8]
1/32 [0.8]
5/128 [1.0]
5/128 [1.0]
Nominal
dimensions
(in)
Diagram below: Piping diameter and thickness
Outside
diameter (mm)
Thickness : in [mm]
R410A
*Use 1/2 H or H pipes.
R22
1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
11/32-23/64 [ 9.1]
1/2-33/64 [13.2]
41/64-21/32 [16.6]
49/64-25/32 [19.7]
—
9.0
13.0
16.2
19.4
23.3
Nominal
dimensions (in)
Flare cutting dimensions
Outside
diameter (mm)
Dimension A ( )
0
-0.4
Unit : in [mm]
R410A R22
1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
43/64 [17.0]
7/8 [22.0]
1-3/64 [26.0]
1-9/64 [29.0]
17.0
22.0
24.0
27.0
36.0
Nominal
dimensions (in)
Flare nut dimensions
Outside
diameter (mm)
Dimension B
Unit: in [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, 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

45
OCH789
2OVERVIEW OF UNITS
2-1. Auxiliary HEATING ON/OFF CONTROL SET-UP
(1) Auxiliary heating operation controls another heat source that depends on the main system's operations,
which means the interlock operation shown in "b)" will be possible.
a)
b) Different Indoor unit applications that can be applied:
(2) Outdoor unit DIPSW5-4 for auxiliary heating control:
Set DIPSW5-4 when power is turned off at unit.
OFF: Disable auxiliary Heating Function (Initial setting)
ON : Enable auxiliary Heating Function
Indoor unit must be R410A UL model for this function to operate.
(3) Determine required indoor fan speed during defrost mode:
To set the fan speed, see the chapter referring to heater control in the indoor unit’s Technical & Service Manual.

6
OCH789
When the set temperature ranges overlap, the previously set pattern (1, 2 or 3) has a priority.
The stage 1 has the highest priority, 2 the second and then 3.
b) Based on above chart listed the sequence of operation on "On ambient decrease"
Stage 1: (TH7 = > 50°F [10
: ]): the outdoor unit runs in HP mode.
Stage 2: (TH7 = 50 to −13°F [10
to −25 : ]): the outdoor unit runs in HP mode with auxiliary heating.
Stage 3: (TH7 = < −13°F [−25
: ]): Auxiliary heating only (Outdoor unit is OFF).
c) Based on above chart listed the sequence of operation on "On ambient increase"
Stage 3: (TH7 = < 32°F [0
: ]): Auxiliary heating only (Outdoor unit is OFF).
Stage 2: (TH7 = > 32 to 68°F [0 to 20
: ]): Auxiliary heating with outdoor unit in HP mode.
Stage 1: (TH7 = > 68°F [20
: ]): Outdoor unit in HP mode only.
(4) Determine fan speed setting during indoor thermo-OFF conditions:
a) These settings are done within Indoor DIPSW1-7 and DIPSW1-8, see chart below for options.
b) Recommended SW1-7 OFF and SW1-8 ON will determine airflow based on "Setting on the remote controller".
Fan speed
setting
Fan speed
setting
OFF ON
SW1-7 SW1-8
OFF OFF Very low
ON OFF Low
OFF ON
Setting on
remote
controller
ON
ON
Stopped
Auxiliary heating
signal
Thermo condition
(5) Setting outdoor unit and auxiliary heat switch over temperatures
When the DIPSW 5-4 is set to "ON", the outdoor unit and the contact output operates as shown below.
a) Outdoor default setting and operations are shown below:
Stage 1
A
mb. decreasing - Outdoor unit HP operation
Amb. increasing - Defrost : Heater contact ON signal
- Other than defrost : Contact OFF
Stage 2
- Outdoor unit HP operation
- Heater contact ON signal
Stage 3
- Outdoor unit OFF (Standby)
- Heater contact ON signal
TH7 = Outdoor temperature
a
−25
-C
[
− 13-F]
b
0
-C
[32-F]
c
10
-C
[50-F]
d
20
-C
[68-F]
Setting on
remote
controller

7
OCH789
(6) Locally procured wiring
A basic connection method is shown.
(i.e. interlocked operation with the electric heater with the fan speed setting on high)
Recommended circuit
CN24
CN22
X
+
X
Remote control Board Relay circuit Adapter
Indoor unit
control board
Outdoor unit
control board
Electric Heater power source
Electric
Heater
Red 1
White 2
Dip switch
SW5-4 "ON"
Preparations in the field Maximum cable length
is 10 m (32ft)
Red 1
Red 2
YellowGreen
FS1
FS2
FS1
FS2
R
S
R
S
CN24
H2
88H
H1
88H
26H
88H
1-phase power
supply
208V, 230V/60Hz
Control board
FS1, 2 ----- Thermal fuse
H1, H2 ----- Heater
26H --------- Overheat protection
thermostat
88H --------- Electromagnetic contactor
Wiring diagram
For relay X use the specifications given below operation coil
Rated voltage: 12 V DC
Power consumption: 0.9W or less
*Use the diode that is recommended by the relay manufacturer at both ends of the relay coil.
The length of the electrical wiring for the PAC-YU24HT is 2 meters (6-1/2 ft)
To extend this length, use sheathed 2-core cable.
Control cable type: CVV, CVS, CPEV, or equivalent.
Cable size: 0.5 mm2to 1.25 mm2(AWG22 to AWG16)
Do not extend the cable more than 10 meters (32 ft).

8
OCH789
2-2. SYSTEM CONSTRUCTION
Branching pipe
components
Branch header
(2 branches)
Branch header
(4 branches)
Branch header
(8 branches)
CMY-Y62-G-E CMY-Y64-G-E CMY-Y68-G-E
Model
Capacity
Cassette Ceiling Ceiling
Concealed Wall Mounted
Ceiling
Suspended
Floor standing
Multi-position
air handling unit
4-way
ow 2 by 2
1-way
ow
Exposed Concealed
PLFY-EP PLFY-P PLFY-P PMFY-P PEFY-P PKFY-P PCFY-P PFFY-P PFFY-P PVFY-P
NEMU-E NCMU-E NFMU-E NBMU-E NMAU NMSU-E NMHU-E NMHSU-E NBMU-E NHMU-E NKMU-E NLMU-E NKMU-E NEMU-E NRMU-E NAMU-E
04 ––––––– – ––– – – – –
05 – – – – – – – – – – – – – – –
06 – – – – – – – – –
08 – – – – – –
12 – – – – –
15 – – – –
18 – – – – – –
24 – – – – – – –
27 – – – – – – – – – – – – – –
30 – – – – – – – – – –
36 – – – – – – – – – – –
48 – – – – – – – – – – – –
54 – – – – – – – – – – – – –
72 ––––––– *–––– – – – –
* Only MXZ-SM60 is connectable.
Outdoor unit
4HP 4.5HP 5HP 7HP
MXZ-SM36NAM-U1
MXZ-SM36NAMHZ-U1 MXZ-SM42NAMHZ-U1 MXZ-SM48NAM-U1
MXZ-SM48NAMHZ-U1 MXZ-SM60NAM-U1
Applicable
indoor unit
Capacity Type 04 to Type 36 Type 04 to Type 54 Type 04 to Type 72
Number of units 1 to 11 unit 1 to 12 unit
Total system
capacity range 50 to 130% of outdoor unit capacity
Remote
controller
Name M-NET remote controller MA remote controller
Model number PAR-F27MEA-E
PAR-U01MEDU PAR-21MAA, PAR-40MAA
Functions
• A handy remote controller for use in
conjunction with the Melans centralized
management system.
• Addresses must be set.
• Addresses setting is not necessary.
–: Not connectable
: Connectable

9
OCH789
Outdoor unit MXZ-SM36NAM-U1
MXZ-SM36NAMHZ-U1 MXZ-SM42NAMHZ-U1 MXZ-SM48NAM-U1 MXZ-SM48NAMHZ-U1 MXZ-SM60NAM-U1
4HP 4.5HP 5HP 7HP
Rated capacity
(kBtu/h)
Cooling 36 42 48 60
Heating 42 48 54 66
Refrigerant R410A
Connectable
indoor unit
Capacity class Type 06 to Type 36
Caution: The indoor unit which rated capacity exceeds
36 kBtu/ h (Type 36) can NOT be connected.
Number of units 2(*1) to 4 units 2(*1) to 5 units 2(*1) to 8 units 2(*1) to 8 units
Total system capacity range 33 to 130% of outdoor
unit capacity
(12 to 46.8 kBtu/h)
29 to 130% of outdoor
unit capacity
(12 to 54.6 kBtu/h)
25 to 130% of outdoor
unit capacity
(12 to 62.4 kBtu/h)
20 to 130% of outdoor
unit capacity
(12 to 78 kBtu/h)
Connectable
branch box
Number of units 1 or 2 units
Connectable indoor unit lineups (Heat pump inverter type)
Model type Model name Capacity class [kBtu/h]
06 09 12 15 18 24 30 36
Deluxe Wall-mounted MSZ-FH06/09/12/15NA, 18NA2
MSZ-FS06/09/12/15/18NA
Designer MSZ-EF09/12/15/18NA(W/B/S)
Standard Wall-mounted MSZ-GL06/09/12/15/18/24NA
Low static ducted*3 *4 SEZ-KD09/12/15/18NA
P-series mid static ducted*3 *4 PEAD-A09/12/15/18/24/30/36AA7
1-way cassette MLZ-KP09/12/18NA(2)
P-series 22*22 4-way cassette SLZ-KF09/12/15NA
P-series 33*33 4-way cassette PLA-A12/18/24/30/36EA7*5
Floor standing MFZ-KJ09/12/15/18NA
Standard Multi-position air handler*2 SVZ-KP12/18/24/30/36NA
●Models other than MXZ-SM60NAM (For each connected branch box)
Number of connecting
multi-position unit Constraints
2
Any indoor units other than ducted units are not
connectable.
1
· The total system wide capacity should be 130% or
below including the ducted unit.
· Only 1 ducted unit can be included in the connection.
Option Optional accessories for indoor units and outdoor units are available.
2- branch pipe (joint): Optional parts
In the case of using 1- branch box No need
In the case of using 2- branch boxes Model name Connection method
MSDD-50AR-E are
MSDD-50BR-E brazing
Branch box PAC-MKA52BC PAC-MKA32BC
Number of branches
(Indoor unit that can be connected)
5 branches
(MAX. 5 units)
3 branches
(MAX. 3 units)
Note: A maximum of 2 branch boxes can be connected to 1 outdoor unit.
●MXZ-SM60NAM (For each connected branch box)
Number of connecting
multi-position unit
Constraints
2
Any indoor units other than ducted unit are not
connectable.
1
· The total system wide capacity should be 100% or
below including the ducted unit.
· Only 1 ducted unit can be included in the connection.
*3 For MXZ-SM60NAM; When connecting the SEZ and PEAD-series units, the total system wide capacity per 1 branch box should be 100% or below including
the
ducted unit s. (Only if connecting to branch box)
*4 When not outside units 60: A branch box can connect to maximum 3 of the
ducted unit s. When connecting with 3 of the ducted unit sper 1 branch box, other
indoor units cannot be connected.
When outside units 60: A branch box can connect to maximum 2 of the
ducted unit s. When connecting with 1 and over 1 of the ducted unit s, the total ability
including of the ducted unit s is 100% and below 100%.
*5 When the system includes 1 unit of
ducted unit s, the number of the maximum connectable indoor units is decreased as follows:
3 for MXZ-SM36NAM(HZ), 4 for MXZ-SM42NAMHZ, and 6 for MXZ-SM48NAM(HZ) and MXZ-SM60NAM
*1 Only one
unit connection is possible with ducted unit.
*2
When connecting a multi-position unit(s), set additional constraints as follows. For connections other than those specied below, consult your dealer.
Select a model according to the
connection method.

10
OCH789
2-3. SYSTEM SPECIFICATIONS
(2) Method for identifying
(1) Outdoor Unit
Power supply
N: Single phase 208/230 V 60 Hz
Multi type heat
pump inverter
outdoor unit
Indicates equivalent to rated cooling capacity.
(kBtu/h)
Control and refrigerant
A: New A control and R410A
MXZ -36SM N AM -U1
Sub-number
Smart Multi
Cooling/Heating capacity indicates the maximum value at operation under the following condition.
Cooling Indoor D.B. 80°F/W.B. 67°F: [D.B. 26.7°C/W.B. 19.4°C]
Outdoor D.B. 95°F/W.B. 75°F: [D.B. 35°C/W.B. 23.9°C]
Heating Indoor D.B. 70°F/W.B. 60°F: [D.B. 21.1°C/W.B. 15.6°C]
Outdoor D.B. 47°F/W.B. 43°F: [D.B. 8.3°C/W.B. 6.1°C]
Service Ref. MXZ-SM36NAM-U1
MXZ-SM36NAMHZ-U1 MXZ-SM42NAMHZ-U1 MXZ-SM48NAM-U1
MXZ-SM48NAMHZ-U1 MXZ-SM60NAM-U1
Capacity Cooling (kBtu/h) 36 42 48 60
Heating (kBtu/h) 42 48 54 66
Compressor (kW) 2.8 2.9 3.4 3.9