Panasonic CS-TZ50TKEW / CU-TZ50TKE Service Manual ▷ View online
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13. Installation and Servicing Air Conditioner using R32
13.1 About R32 Refrigerant
For air conditioning refrigerants such as R410A, the refrigerants were collected back in order to prevent their air
dissipation, to curbe the global warming impact, in case they were released into the atmosphere. In the “4th
Environmental Basic Plan”, 80% reduction of greenhouse gas emissions by 2050 is required, and due to this
requirement, further reduction in the emission of high greenhouse effect gas, such as CFCs, is required. Therefore,
the conversion of air conditioning refrigerant into the ones who has smaller greenhouse effect, even if it is dissipated
into the atmosphere, became our responsibility.
dissipation, to curbe the global warming impact, in case they were released into the atmosphere. In the “4th
Environmental Basic Plan”, 80% reduction of greenhouse gas emissions by 2050 is required, and due to this
requirement, further reduction in the emission of high greenhouse effect gas, such as CFCs, is required. Therefore,
the conversion of air conditioning refrigerant into the ones who has smaller greenhouse effect, even if it is dissipated
into the atmosphere, became our responsibility.
Nevertheless, in case of air conditioning refrigerant, it would be the best if there is a refrigerant which has smaller
impact on global warming, but ensures good energy efficiency and performance, and is safe; however, there is no
such refrigerant which satisfies all these conditions. As a result, we have been considering the practical usage, within
the safety frame-work, of R32 refrigerant which has short lifetime in the atmosphere, and has smaller effect of global
warming, but is slightly flammable.
In 2004, due to the revision of air conditioner safety standards by the International Electro-safety Commission (IEC),
the safety standards of air conditioners using slightly flammable refrigerant was issued. In 2010, the regulations of
American Society of Heating, Refrigerating and Air-Conditioning Engineers in the United States (ANSI/ASHRAE34)
was issued adopting the grades for refrigerants which are difficult to inflame due to their slow burning rates, and as a
result have smaller damages in cases of fire. The burning rate of R32 is lower by 10cm / per second, and safety
standardization for various usage is now being processed.
impact on global warming, but ensures good energy efficiency and performance, and is safe; however, there is no
such refrigerant which satisfies all these conditions. As a result, we have been considering the practical usage, within
the safety frame-work, of R32 refrigerant which has short lifetime in the atmosphere, and has smaller effect of global
warming, but is slightly flammable.
In 2004, due to the revision of air conditioner safety standards by the International Electro-safety Commission (IEC),
the safety standards of air conditioners using slightly flammable refrigerant was issued. In 2010, the regulations of
American Society of Heating, Refrigerating and Air-Conditioning Engineers in the United States (ANSI/ASHRAE34)
was issued adopting the grades for refrigerants which are difficult to inflame due to their slow burning rates, and as a
result have smaller damages in cases of fire. The burning rate of R32 is lower by 10cm / per second, and safety
standardization for various usage is now being processed.
13.2 Characteristics of R32 Refrigerant
1. Chemical
Characteristics
R32 is one of the refrigerants used in R410A, has almost no toxicity, and chemically stable compound formed by
hydrogen, carbon and fluorine.
hydrogen, carbon and fluorine.
R32 has short lifetime of 4 to 9 years in case of being released into the atmosphere; therefore, it has smaller
greenhouse gas effect but has slight inflammability because of the large proportion of hydrogen.
Chemical Characteristic Table of R32, R410A and R22.
greenhouse gas effect but has slight inflammability because of the large proportion of hydrogen.
Chemical Characteristic Table of R32, R410A and R22.
R32
R410A
R22
Chemical Formula
CH2F2
CH2F2 / CHF2CF3
CHCLF2
Composition
(mixture ratio wt.%)
Single Composition
R32 / R125A
Single Composition
(50 / 50 wt.%)
Boiling Point (°C)
-51.7
-51.5
-40.8
Pressure (physical) *1
3.14
3.07
1.94
Capacity (physical) *2
160
141
100
COP (physical) *3
95
91
100
Ozone Depletion Potential (ODP)
0
0
0.055
Global Warming Potential
(GWP) *4
675 2090 1810
Inflammability *5
Slightly Inflammable
(A2L)
Non-inflammable (A1)
Non-inflammable (A1)
Toxicity None None None
*1：Physical property of temperature condition 50°C
*2：Relative value of temperature condition 0/50°C, providing R22=100
*3：Te/Tc/SC/SH=5/50/3/0°C
*4：GWP=Global Warming Potential, each figure is based on “4
th
IPCC4 Report”
*5：Based on ANSI / ASHRAE std. 34-2010
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2. Characteristic of Pressure
As shown in Table 2, R32 does not have much difference in vapor pressure at the same refrigerant temperature
comparing to R410A, but comparing to R22, it is higher at 1.6 times more. Thus, the same as in case of R410A, it is
necessary to do installation and service using high-pressure tools and components.
Table 2. Saturated vapor pressure comparison table
As shown in Table 2, R32 does not have much difference in vapor pressure at the same refrigerant temperature
comparing to R410A, but comparing to R22, it is higher at 1.6 times more. Thus, the same as in case of R410A, it is
necessary to do installation and service using high-pressure tools and components.
Table 2. Saturated vapor pressure comparison table
(Unit: MPa)
Temperature
Refrigerant
R32
R410A
R22
-20 0.30 0.30 0.14
0 0.71
0.70
0.40
20 1.37 1.35 0.81
40 2.38 2.32 1.43
60 3.84 3.73 2.33
65 4.29 4.17 2.60
40 2.38 2.32 1.43
60 3.84 3.73 2.33
65 4.29 4.17 2.60
Reference： Thermal properties table of Japan Society of Refrigerating and Air Conditioning Engineers (60, 65°C)
NIST REFPROP V8.0 (-20 ~ 40°C)
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13.3 Refrigerant piping installation • Tools used in services
13.3.1 Required
Tools
R32 refrigerant air conditioners use the common parts as R410A air conditioners for two-way valves and three-way
valves (diameters of service ports); thus, they maintain commonality in the maintenance of the compressive strength,
the size of pipe flaring, and the size of flare nuts as R410A. Therefore, for refrigerant pipe installation and services,
you can use tools for R410A.
However, mixing of refrigerants is not allowed, so that you have to separate the cylinders for the recovery of
refrigerants.
Tools used for installation •
valves (diameters of service ports); thus, they maintain commonality in the maintenance of the compressive strength,
the size of pipe flaring, and the size of flare nuts as R410A. Therefore, for refrigerant pipe installation and services,
you can use tools for R410A.
However, mixing of refrigerants is not allowed, so that you have to separate the cylinders for the recovery of
refrigerants.
Tools used for installation •
relocation •
replacement of air conditioning units
Works
R32
R410A
R22
Flaring
Flare tools for R410A (clutch type)
Flare tools for R22 (clutch type)
Connection of pipes
Torque wrench (diameter 1/4 3/8)
Torque wrench (diameter 1/2 5/8) *1
Toque wrench (diameter 1/2 5/8)
Manifold gauge charging hose
R32 & R410A Common (As at November 2013)
R22 Only
Air purging
Vacuum pump + Reducer / expander
Vacuum pump
Gas leakage test
Detection liquid or soup water, HFC detector
*1. Nut diameters of 1/2 5/8, the size of torque wrench common with R410A
For other installation, you can use general tools such as screw drivers (+, -), metal saws, electric drills, long-nose
pliers, hole core drills (ø70 or ø65), linen tape, levels, temperature gauges, clamp meters, electric knives, nippers,
pipe cutters, reamers or scrapers, spring benders, (diameters 1/4 3/8 1/2 5/8), monkey wrenches, fixing wrenches
(17 or 12 mm), feeler gauges, hexagon wrenches (4 mm), testers, megohm testers, etc.
Tools used for services
Works
R32
R410A
R22
Insertion of refrigerant
Digital scale for refrigerant charging, refrigerant cylinders, cylinder adopters and packing *a
Recovery of refrigerant
Refrigerant recovery devices, refrigerant cylinders, manifold gauges, charging hoses *b
*a. Use cylinder for each refrigerant, cylinder adopter and packing.
*b. Use refrigerant recovery cylinder separately for each refrigerant (no mixture of refrigerant allowed). Please be
aware that there are some refrigerant collection devices which do not have self-certification.
13.3.2 Tools for R32 (common with R410A)
1. Flare
gauges
Use flare gauges when you perform flaring with flare
tools (crutch type). Flare gauges are used to set the
pipe ends at 0.5 ~ 1.5 mm from clump bars of flare
tools.
Flare gauges
tools (crutch type). Flare gauges are used to set the
pipe ends at 0.5 ~ 1.5 mm from clump bars of flare
tools.
Flare gauges
2. Flare tools (clutch type)
Flare tools have larger holes of clump bars in order
to set the pipe end at 0 ~ 0.5 mm, and have stronger
springs inside to ensure solid flaring torques. These
flare tools can be used commonly for R22.
Flare tools (clutch type)
Flare tools have larger holes of clump bars in order
to set the pipe end at 0 ~ 0.5 mm, and have stronger
springs inside to ensure solid flaring torques. These
flare tools can be used commonly for R22.
Flare tools (clutch type)
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3. Torque wrenches (diameters 1/2, 5/8)
In order to strengthen the compressive strength, the
diameters of wrenches change depending on the flare
nut sizes.
In order to strengthen the compressive strength, the
diameters of wrenches change depending on the flare
nut sizes.
Torque wrenches
Differences in torque wrenches
R32
(common R410A)
R22
1/2
(diameter × torque)
26 mm × 55 N•m
(550 kgf•m)
24 mm × 55 N•m
(550 kgf•m)
5/8
(diameter × torque)
29 mm × 65 N•m
(650 kgf•m)
27 mm × 65 N•m
(650 kgf•m)
4. Manifold
gauges
R22 gauges cannot be used because of the high
pressures.
Each port of manifold has different shapes in order
to prevent inserting wrong refrigerant.
*However, the port shape for R410A and R32 is the
same; therefore, attention need to be paid not to insert
wrong refrigerant.
pressures.
Each port of manifold has different shapes in order
to prevent inserting wrong refrigerant.
*However, the port shape for R410A and R32 is the
same; therefore, attention need to be paid not to insert
wrong refrigerant.
Differences in high/low pressure gauges
R32
(common R410A)
R22
High pressure
gauges (red)
-0.1 ~ 5.3 MPa
-76 cmHg ~ 53 kgf / cm
2
-76 cmHg ~ 35 kgf / cm
2
Low pressure
gauges (blue)
-0.1 ~ 3.8 MPa
-76 cmHg ~ 38 kgf / cm
2
-76 cmHg ~ 17 kgf / cm
2
Difference in manifold port sizes
R32
(common R410A)
R22
Port sizes
1/2 UNF20
7/16 UNF20
5. Charging
hoses
The pressure resistance of charge hoses is increased.
At the same time, the material is changed to HFC
resistant, and the size of each manifold adopter is
changed, as the port size of manifold gauge itself.
Further, some hoses are with anti-gas pressure
backflow valves placed near the adopters. (hoses with
the valves recommended)
At the same time, the material is changed to HFC
resistant, and the size of each manifold adopter is
changed, as the port size of manifold gauge itself.
Further, some hoses are with anti-gas pressure
backflow valves placed near the adopters. (hoses with
the valves recommended)
Manifold gauges / Charging hoses
Differences in charging hoses
R32
(common R410A)
R22
Pressure
Resistance
Normal
operation
pressure
5.1 MPa
(52 kgf / cm
2
)
3.4 MPa
(35 kgf / cm
2
)
Burst
pressure
27.4 MPa
(280 kgf / cm
2
)
17.2 MPa
(175 kgf / cm
2
)
Material
HNBR rubber
Internal nylon
Internal nylon
coating
NBR rubber
6. Vacuum pump and Vacuum pump adopter
When using a vacuum pump, it is necessary to set a
solenoid valve in order to prevent backflow of vacuum
pump oil into the charge hoses, and use a vacuum
pump with oil backflow prevention function, or use the
vacuum pump with vacuum pump adopter.
If vacuum pump oil（mineral oil-based）mixes with
R410A (R32), it may cause damage to the machine.
When using a vacuum pump, it is necessary to set a
solenoid valve in order to prevent backflow of vacuum
pump oil into the charge hoses, and use a vacuum
pump with oil backflow prevention function, or use the
vacuum pump with vacuum pump adopter.
If vacuum pump oil（mineral oil-based）mixes with
R410A (R32), it may cause damage to the machine.
Vacuum pump
Vacuum pump adopter
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