Mitsubishi Electric MXZ-2A20NA-1 User manual

Inverter-controlled multi system type
Models
SERVICE MANUAL
CONTENTS
1. TECHNICAL CHANGES ····································2
2. PART NAMES AND FUNCTIONS······················6
3. INDOOR UNITS COMBINATION·······················7
4. SPECIFICATION···············································10
5. OUTLINES AND DIMENSIONS ·······················12
6. WIRING DIAGRAM ··········································15
7. REFRIGERANT SYSTEM DIAGRAM··············19
8. DATA·································································23
9. ACTUATOR CONTROL····································38
10. SERVICE FUNCTIONS·····································38
11. TROUBLESHOOTING······································40
12. DISASSEMBLY INSTRUCTIONS·····················57
13. PARTS LIST······················································66
14. RoHS PARTS LIST···········································74
15. OPTIONAL PARTS···········································86
No. OB444
REVISED EDITION-B
SPLIT-TYPE, HEAT PUMPAIR CONDITIONERS
The Slim Line.
From Mitsubishi Electric.
33223
9700058
TM
OUTDOOR UNIT
MXZ-2A20NA
MXZ-2A20NA -
MXZ-3A30NA
MXZ-3A30NA - 1
1
MXZ-2A20NA
MXZ-2A20NA - 1
HFC
utilized
R410A
Indoor unit service manual
MSZ-A·NA Series (OB450)
Revision B:
• MXZ-2A20NA - and MXZ-3A30NA -
have been added. 11
NOTE:
• This service manual describes technical
data of the outdoor units.
• RoHS compliant products have <G> mark
on the spec name plate.
For servicing of RoHS compliant products,
refer to the RoHS Parts List.
Please void OB444 REVISED EDITION-A.
OB444B--1.qxp 07.4.17 4:27 PM Page 1

TECHNICAL CHANGES
2
1
MXZ-2A20NA
New model
MXZ-30TN2 ➔MXZ-3A30NA
1. Combinations of connectable indoor units have been increased.
2. Capacity class of connectable indoor units have been made larger.
3. Compressor has been changed. (THV247FBA ➔TNB220FMCH)
4. Outdoor fan motor has been changed. (RA6N60-AA ➔RC0J60-AB)
5. Refrigerant has been changed. (R22 ➔R410A)
6. Refrigerant system diagram has been changed.
• 1 of 2 high pressure switch has been removed.
• Accumulator has been removed.
• Receiver has been added.
7. Communication system has been changed.
8. Power supply way has been changed(change to supply to outdoor unit).
9. Evaporation temperature thermistor has been added.
10. Ambient temperature thermistor has been added.
MXZ-2A20NA ➔MXZ-2A20NA -
1. Compressor has been changed. (SNB130FPDH1 ➔SNB130FQBH1)
2. Gas pipe temperature thermistor has been removed.
3. Pre-heat control has been added.
4. Electronic control P.C. board has been changed.
5. Power board has been changed.
MXZ-3A30NA ➔MXZ-3A30NA -
1. Ball valve has been changed to stop valve.
2. Gas pipe temperature thermistor has been removed.
3. Pre-heat control has been added.
4. Auto line correcting function has been added.
5. Noise filter P.C. board has been changed.
6. Electronic control P.C. board has been changed.
7. Weight has been changed. (158lb. ➔ 148lb.)
1
1
Revision A:
• RoHS PARTS LIST has been added.
Revision B:
• MXZ-2A20NA - and MXZ-3A30NA - have been added.
11
OB444B--1.qxp 07.4.17 4:27 PM Page 2

3
INFORMATION FOR THE AIR CONDITIONER WITH R410A REFRIGERANT
• This room air conditioner adopts HFC refrigerant (R410A) which never destroys the ozone layer.
• Pay particular attention to the following points, though the basic installation procedure is same as that for R22 air
conditioners.
1As R410A has working pressure approximate 1.6 times as high as that of R22, some special tools and piping parts/
materials are required. Refer to the table below.
2Take sufficient care not to allow water and other contaminations to enter the R410A refrigerant during storage and
installation, since it is more susceptible to contaminations than R22.
3For refrigerant piping, use clean, pressure-proof parts/materials specifically designed for R410A. (Refer to 2. Refrigerant
piping.)
4Composition change may occur in R410A since it is a mixed refrigerant. When charging, charge liquid refrigerant to prevent
composition change.
Refrigeration
oil
Refrigerant
New refrigerant
R410A
HFC-32: HFC-125 (50%:50%)
Pseudo-azeotropic refrigerant
Not included
A1/A1
72.6
-60.5
225.82
3.995
Non combustible
0
1730
From liquid phase in cylinder
Possible
Incompatible oil
Non
Non
Previous refrigerant
R22
R22 (100%)
Single refrigerant
Included
A1
86.5
-41.4
136.34
2.772
Non combustible
0.055
1700
Gas phase
Possible
Compatible oil
Light yellow
Non
Refrigerant
Composition (Ratio)
Refrigerant handling
Chlorine
Safety group (ASHRAE)
Molecular weight
Boiling point (-F)
Steam pressure [77-F](PSIG)
Saturated steam density [77-F](lb/ft3)
Combustibility
ODP w1
GWP w2
Refrigerant charge method
Additional charge on leakage
Kind
Color
Smell
w1:Ozone Depletion Potential : based on CFC-11
w2 :Global Warming Potential : based on CO2
OB444B--1.qxp 07.4.17 4:27 PM Page 3

4
R410A tools Can R22 tools be used?
Gas leak detector
R410A has high pressures beyond the measurement range of existing
gauges.
Hose material have been changed to improve the pressure resistance.
Dedicated for HFC refrigerant.
1/4in. and 3/8in.
Description
Clamp bar hole has been enlarged to reinforce the spring strength in the tool.
Provided for flaring work (to be used with R22 flare tool).
Provided to prevent the back flow of oil. This adapter enables you to use
vacuum pumps.
It is difficult to measure R410Awith a charging cylinder because the
refrigerant bubbles due to high pressure and high-speed vaporization.
No
No
No
Yes
Yes
New
New
New
Gauge manifold
Charge hose
Torque wrench
Flare tool
Flare gauge
Vacuum pump
adapter
Electronic scale for
refrigerant charging
No : Not Substitutable for R410A Yes : Substitutable for R410A
No 1/2in. and 5/8in.
1.Tools dedicated for the air conditioner with R410A refrigerant
The following tools are required for R410A refrigerant. Some R22 tools can be substituted for R410A tools.
New Specification Current Specification
The incompatible refrigeration oil easily separates from
refrigerant and is in the upper layer inside the suction muffler.
Raising position of the oil back hole enables to back the
refrigeration oil of the upper layer to flow back to the
compressor.
Since refrigerant and refrigeration oil are compatible,
refrigeration oil goes back to the compressor through the
lower position oil back hole.
Compressor
Suction muffler
Oil back hole
refrigeration oil
Refrigerant
Compressor
Suction muffler
Oil back hole
refrigeration oil /Refrigerant
Compressor
-22 -4 14 32 50 68 86 104 122 140
-73
0
73
145
218
290
363
435
508
580
(PSIG)
R410A
R22
Conversion chart of refrigerant temperature and pressure
Saturated liquid pressure
(-F)
OB444B--1.qxp 07.4.17 4:27 PM Page 4

5
R410A
Pipe diameter
(inch)
1/4
3/8
1/2
5/8
17 [11/16]
22 [7/8]
26 [1-1/32]
29 [1-5/32]
Dimension of flare nut
R22
(inch) [inch]
17 [11/16]
22 [7/8]
24 [15/16]
27 [1-1/16]
2Flaring work and flare nut
Flaring work for R410A pipe differs from that for R22 pipe.
For details of flaring work, refer to Installation manual “FLARING WORK”.
3.Refrigeration oil
Apply the special refrigeration oil (accessories: packed with indoor unit) to the flare and the union seat surfaces.
4.Air purge
•Do not discharge the refrigerant into the atmosphere.
Take care not to discharge refrigerant into the atmosphere during installation, reinstallation, or repairs to the refrigerant
circuit.
•Use the vacuum pump for air purging for the purpose of environmental protection.
5.Additional charge
For additional charging, charge the refrigerant from liquid phase of the gas cylinder.
If the refrigerant is charged from the gas phase, composition change may occur in the refrigerant inside the cylinder and the
outdoor unit. In this case, ability of the refrigeration cycle decreases or normal operation can be impossible. However,
charging the liquid refrigerant all at once may cause the compressor to be locked. Thus, charge the refrigerant slowly.
2.Refrigerant piping
1Specifications
Use the copper or copper-alloy seamless pipes for refrigerant that meet the following specifications.
Wall thickness
(inch)
Outside diameter
(inch)
1/4
3/8
1/2
5/8
0.0315
0.0315
0.0315
0.0394
Heat resisting foam plastic
Specific gravity 0.045 Thickness 0.315 inch
Insulation material
Electronic scale for refrigerant charging
Outdoor unit
Refrigerant gas
cylinder
operating valve
Refrigerant gas cylinder
for R410A with siphon
Refrigerant (liquid)
Service port
Gauge manifold
valve (for R410A)
Union
Liquid pipe
Gas pipe
Stop valve
Indoor unit
Charge hose (for R410A)
OB444B--1.qxp 07.4.17 4:27 PM Page 5