Mitsubishi Electric SUZ-KA24NAHZ User manual

SERVICE MANUAL
CONTENTS
1. REFERENCE MANUAL····························· 2
2. SAFETY PRECAUTION····························· 2
3. FEATURES ············································· 6
4. SPECIFICATIONS ···································· 7
5. DATA······················································ 9
6. OUTLINES AND DIMENSIONS················· 13
7. WIRING DIAGRAM································· 15
8. WIRING SPECIFICATIONS ······················ 17
9. REFRIGERANT SYSTEM DIAGRAM ············ 20
10. TROUBLESHOOTING ····························· 23
11. EASY MAINTENANCE FUNCTION ············ 74
12. FUNCTION SETTING ······························ 76
13. MONITORING THE OPERATION DATA BY THE REMOTE CONTROLLER ··78
14. DISASSEMBLY PROCEDURE ·················· 87
15. REMOTE CONTROLLER························100
No. OCH754
REVISED EDITION-A
R410A
December 2020
Note:
• This manual describes
service data of the
outdoor units only.
PARTS CATALOG (OCB754)
[Model Name] [Service Ref.]
SUZ-KA24NAHZ SUZ-KA24NAHZ
SUZ-KA30NAHZ SUZ-KA30NAHZ
SUZ-KA36NAHZ SUZ-KA36NAHZ
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
SUZ-KA30NAHZ
SUZ-KA36NAHZ
SUZ-KA24NAHZ
Revision:
• Some descriptions
have been modified in
REVISED EDITION-A.
OCH754 is void.

2
OCH754A
2SAFETY PRECAUTION
1REFERENCE MANUAL
Before obtaining access to terminal, all supply circuits must be disconnected.
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 off the power-supply breaker.
• Discharge the condenser before the work involving the electric parts.
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 off 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.
2-1. ALWAYS OBSERVE FOR SAFETY
Model Name Service Ref. Service Manual No.
Parts Catalog No.
PEAD-A24/30/36AA7 PEAD-A24/30/36AA7 HWE1608A
BWE01629A
SVZ-KP24/30/36NA SVZ-KP24/30/36NA MD-1404-K019
MD-1404-K018
INDOOR UNIT SERVICE MANUAL

3
OCH754A
Cautions for units utilizing refrigerant R410A
2-2. CAUTIONS RELATED TO NEW REFRIGERANT
Use new refrigerant pipes.
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 small amount.
In the case of using the existing pipes for R22, be careful
with the following:
· Be sure to clean the pipes and make sure that the insides
of the pipes are clean.
· Change flare nut to the one provided with this product.
Use a newly flared pipe.
· Avoid using thin 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.
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil, etc.
If large amount of mineral oil enters, that can cause deterio-
ration of refrigerant oil, etc.
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
Use the specified refrigerant only.
Never use any refrigerant other than that specified.
Doing so may cause a burst, an explosion, or fire when the
unit is being used, serviced, or disposed of.
Correct refrigerant is specified 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.
Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.
Store the piping indoors, and 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.

4
OCH754A
Electric weighing scale
Unit
[3] Service tools
Use the below service tools as exclusive tools for R410A refrigerant.
No. Tool name Specifications
1
Gauge manifold · Only for R410A
· Use the existing fitting specifications.
· Use high-tension side pressure of 5.3 MPa·G or over.
2Charge hose · Only for R410A
· Use pressure performance of 5.09 MPa·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 —
[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.
[2] Additional refrigerant charge
When charging directly from cylinder
· Check that cylinder for R410A on the market is a syphon type.
· Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.)

5
OCH754A
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 time 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 inch [0.7mm] or below.)
Nominal
dimensions (in)
Outside
diameter (mm)
Thickness: in (mm)
R410A R22
1/4 6.35 1/32 (0.8) 1/32 (0.8)
3/8 9.52 1/32 (0.8) 1/32 (0.8)
1/2 12.70 1/32 (0.8) 1/32 (0.8)
5/8 15.88 5/128 (1.0) 5/128 (1.0)
3/4 19.05 — 5/128 (1.0)
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 refriger-
ants. Therefore, to enhance air tightness 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 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.
Dimension A
Dimension B
3Tools for R410A (The following table shows whether conventional tools can be used or not.)
Tools and materials Use R410A tools Can R22 tools be used?
Gauge manifold Air purge, refrigerant charge and
operation check
Tool exclusive for R410A
Charge hose Tool exclusive for R410A
Gas leak detector Gas leak check Tool for HFC refrigerant
Refrigerant recovery equipment Refrigerant recovery Tool exclusive for R410A
Refrigerant cylinder Refrigerant charge Tool exclusive for R410A
Applied oil Apply to ared section Ester oil and alkylbenzene oil
(minimum amount)
Safety charger Prevent compressor malfunction when
charging refrigerant by spraying liquid
refrigerant
Tool exclusive for R410A
Charge valve Prevent gas from blowing out when
detaching charge hose
Tool exclusive for R410A
Vacuum pump Vacuum drying and air purge Tools for other refrigerants can be
used if equipped with adopter for
reverse ow check
(Usable if equipped with adopter for
reverse ow)
Flare tool Flaring work of piping Tools for other refrigerants can be
used by adjusting aring dimension
(Usable by adjusting aring
dimension)
Bender Bend the pipes
Tools for other refrigerants can be used
Pipe cutter Cut the pipes Tools for other refrigerants can be used
Welder and nitrogen gas cylinder Weld the pipes Tools for other refrigerants can be used
Refrigerant charging scale Recover refrigerant Tools for other refrigerants can be used
Vacuum gauge or thermistor vacuum
gauge and vacuum valve
Check the degree of vacuum. (Vacuum
valve prevents back ow of oil and
refrigerant to thermistor vacuum gauge)
Tools can be used for other
refrigerants.
Charging cylinder Recover refrigerant Tool exclusive for R410A
: 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.
Diagram below: Piping diameter and thickness
Nominal
dimensions (in)
Outside
diameter (mm)
Thickness: in (mm)
R410A R22
1/4 6.35 1/32 (0.8) 1/32 (0.8)
3/8 9.52 1/32 (0.8) 1/32 (0.8)
1/2 12.70 1/32 (0.8) 1/32 (0.8)
5/8 15.88 5/128 (1.0) 5/128 (1.0)
3/4 19.05 — 5/128 (1.0)
Flare nut dimensions
Nominal
dimensions (in)
Outside
diameter (mm)
Dimension B: in (mm)
R410A R22
1/4 6.35 43/64 (17.0) 17.0
3/8 9.52 7/8 (22.0) 22.0
1/2 12.70 1-3/64 (26.0) 24.0
5/8 15.88 1-9/64 (29.0) 27.0
3/4 19.05 — 36.0

6
OCH754A
3 FEATURES
CHARGELESS SYSTEM
PRE-CHARGED REFRIGERANT IS SUPPLIED FOR PIPING LENGTH AT SHIPMENT.
Maximum 100 ft, 30 m
The refrigerant circuit with LEV(Linear Expansion Valve) and power receiver always control the optimal refrigerant level
regardless of the length (maximum:100 ft [30 m] and minimum: 16 ft [5 m]) of piping. The additional refrigerant charg-
ing work during installation often causes problems. It is completely eliminated by chargelss system. This unique system
improves the quality and reliability of the work done. It also helps to speed up the installation time.
SUZ-KA30NAHZ
SUZ-KA36NAHZ
SUZ-KA24NAHZ

7
OCH754A
4 SPECIFICATIONS
Service Ref. SUZ-KA24NAHZ SUZ-KA30NAHZ
Power supply Phase Single
Cycle 60 Hz
Voltage 208/230 V
MCA A 17 24
MOCP A 27 40
Breaker size A 25 35
External nish Munsell 3Y 7.8/1.1
Heat exchanger Plate n coil
Defrost method Reverse cycle
Crankcase heater kW —
Compressor Hermetic
Model DNB28FBAMT ANB33FJMMT
Motor output kW 2.2 2.5
R.L.A. 9.0 18.0
L.R.A. 18.0 27.5
Starter type Inverter
Fan Fan(drive) × No. Propeller fan x 1 Propeller fan x 2
Fan motor output kW 0.074 0.074 + 0.074
Fan motor F.L.A. 0.33 0.33 + 0.33
Airow m3/min 58 115
CFM 2050 4060
Sound pressure level (SPL) Cooling dB 52 52
Heating dB 53 53
Protection devices HP switch
Comp. Surface thermistor
Dimensions W in 37-13/32 41-11/32
D in 12-63/64+63/64
H in 37-1/8 52-43/64
W mm 950 1050
D mm 330 + 25
H mm 943 1338
Weight lb 190 261
kg 86 118
Refrigerant R410A
Charged lb 7.72 11.46
kg 3.5 5.2
Control Linear expansion valve
Oil Charged Model FVC68D FV50S
oz 34 47
L 1.0 1.4
Refrigerant piping Pipe size O.D. Liquid in 3/8
mm 9.52
Pipe size O.D. Gas in 5/8
mm 15.88
Connection method Indoor Flared
Connection method Outdoor Flared
Height di󰀨erence IU-OU ft Maximum 100
m Maximum 30
Piping length ft Maximum 165 Maximum 245
m Maximum 50 Maximum 75

8
OCH754A
Service Ref. SUZ-KA36NAHZ
Power supply Phase Single
Cycle 60Hz
Voltage 208/230 V
MCA A 26
MOCP A 42
Breaker size A 35
External nish Munsell 3Y 7.8/1.1
Heat exchanger Plate n coil
Defrost method Reverse cycle
Crankcase heater kW —
Compressor Hermetic
Model ANB33FJMMT
Motor output kW 2.5
R.L.A. 18.0
L.R.A. 27.5
Starter type Inverter
Fan Fan(drive) × No. Propeller fan x 2
Fan motor output kW 0.074 + 0.074
Fan motor F.L.A. 0.33 + 0.33
Airow m3/min 115
CFM 4060
Sound pressure level (SPL) Cooling dB 52
Heating dB 53
Protection devices HP switch
Comp. Surface thermistor
Dimensions W in 41-11/32
D in 12-63/64+63/64
H in 52-43/64
W mm 1050
D mm 330 + 25
H mm 1338
Weight lb 261
kg 118
Refrigerant R410A
Charged lb 11.46
kg 5.2
Control Linear expansion valve
Oil Charged Model FV50S
oz 47
L 1.4
Refrigerant piping Pipe size O.D. Liquid in 3/8
mm 9.52
Pipe size O.D. Gas in 5/8
mm 15.88
Connection method Indoor Flared
Connection method Outdoor Flared
Height di󰀨erence IU-OU ft Maximum 100
m Maximum 30
Piping length ft Maximum 245
m Maximum 75

9
OCH754A
5-1. REFILLING REFRIGERANT CHARGE (R410A: oz, kg)
Service Ref. Piping Length (one way) Factory
Charged
70 ft 80 ft 90 ft 100 ft
20 m 24 m 27 m 30 m
SUZ-KA24NAHZ
-7
oz
14
oz
21
oz
123
oz
-0.2
kg
0.4
kg
0.6
kg
3.5
kg
SUZ-KA30NAHZ
SUZ-KA36NAHZ ----
183
oz
5.2
kg
5-2. COMPRESSOR TECHNICAL DATA
Winding temperature at 68°F [20°C]
Service Ref. SUZ-KA24NAHZ SUZ-KA30NAHZ SUZ-KA36NAHZ
Compressor model DNB28FBAMT ANB33FJMMT
Winding Resistance (Ω) U - V 0.74 0.188
U - W 0.74 0.188
W - V 0.74 0.188
5DATA
For pipes longer than 70 ft, additional charge is required.

10
OCH754A
5-3. NOISE CRITERION CURVES
10
20
30
40
50
60
70
80
90
63 125 250 500 1000 2000 4000 8000
COOLING
MODE
HEATING
52
SPL(dB)
53
LINE
OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002 µbar)
BAND CENTER FREQUENCIES, Hz
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
5 ft
3.3 ft
MICROPHONE
UNIT
GROUND
SUZ-KA24NAHZ
10
20
30
40
50
60
70
80
90
63 125 250 500 1000 2000 4000 8000
OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002 µbar)
BAND CENTER FREQUENCIES, Hz
COOLING
MODE
HEATING
52
SPL(dB)
53
LINE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
SUZ-KA30NAHZ
SUZ-KA36NAHZ