Mitsubishi Electric City Multi CMB-WP108V-G, Service Manual

Page: 22 / 301

[
I
Read Before Servicing ]
- 13 - HWE1113B GB
[11] Characteristics of the Conventional and the New Refrigerants
1. Chemical property
As with R22, the new refrigerant (R410A) is low in toxicity and chemically stable nonflammable refrigerant.
However, because the specific gravity of vapor refrigerant is greater than that of air, leaked refrigerant in a closed room will
accumulate at the bottom of the room and may cause hypoxia.
If exposed to an open flame, refrigerant will generate poisonous gases. Do not perform installation or service work in a con-
fined area.
*1 When CFC11 is used as a reference
*2 When CO
2
is used as a reference
2. Refrigerant composition
R410A is a pseudo-azeotropic HFC blend and can almost be handled the same way as a single refrigerant, such as R22. To
be safe, however, draw out the refrigerant from the cylinder in the liquid phase. If the refrigerant in the gaseous phase is drawn
out, the composition of the remaining refrigerant will change and become unsuitable for use.
If the refrigerant leaks out, it may be replenished. The entire refrigerant does not need to be replaced.
3. Pressure characteristics
The pressure in the system using R410A is 1.6 times as great as that in the system using R22.
New Refrigerant (HFC type) Conventional Refriger-
ant (HCFC type)
R410A R407C R22
R32/R125 R32/R125/R134a R22
Composition (wt%) (50/50) (23/25/52) (100)
Type of Refrigerant Pseudo-azeotropic
Refrigerant
Non-azeotropic
Refrigerant
Single Refrigerant
Chloride Not included Not included Included
Safety Class A1/A1 A1/A1 A1
Molecular Weight 72.6 86.2 86.5
Boiling Point (°C/°F) -51.4/-60.5 -43.6/-46.4 -40.8/-41.4
Steam Pressure
(25°C,MPa/77°F,psi) (gauge) 1.557/226 0.9177/133 0.94/136
Saturated Steam Density
(25°C,kg/m
3
/77°F,psi)
64.0 42.5 44.4
Flammability Nonflammable Nonflammable Nonflammable
Ozone Depletion Coefficient (ODP)
*1
0 0 0.055
Global Warming Coefficient (GWP)
*2
1730 1530 1700
Refrigerant Charging Method Refrigerant charging in
the liquid state
Refrigerant charging in
the liquid state
Refrigerant charging in
the gaseous state
Replenishment of Refrigerant after a Refrigerant
Leak Available Available Available
Temperature (°C/°F)
Pressure (gauge)
R410A R407C R22
MPa/psi MPa/psi MPa/psi
-20/-4 0.30/44 0.18/26 0.14/20
0/32 0.70/102 0.47/68 0.40/58
20/68 1.34/194 0.94/136 0.81/117
40/104 2.31/335 1.44/209 1.44/209
60/140 3.73/541 2.44/354 2.33/338
65/149 4.17/605 2.75/399 2.60/377