17
Pressurize the equipment with nitrogen up to the design pressure and then judge the equipment's air tightness, taking
temperature variations into account.
When investigating leakage locations using a refrigerant, be sure to use R32.
Insure that R32 is in a liquid state when charging.
Use of oxygen as the pressurized gas may cause an explosion.
Charging with R32 gas will lead the composition of the remaining refrigerant in the cylinder to change and then this
refrigerant can not be used.
R32 leakage Test
No changes from the conventional method. Note that a refrigerant leakage detector for R22 or R410A cannot detect R32
leakage.
Halide torch
NO
R22 or R407C leakage detector
NO
Items to be strictly observed :
Reasons:
Because R32 is a simulated azeotropic refrigerant, it can be handled in almost the same manner as a refrigerant such as
R410A. Howerver, if the refrigerant is removed in the vapor phase, the composition of the refrigerant in the cylinder will
somewhat change.
Remove the refrigerant in the liquid phase. Additional refrigerant may be added in case of a refrigerant leak.
Characteristics of the Conventional and the New Refrigerants
Required accuracy of the vacuum gauge
Use a vacuum gauge that can measure up to 650Pa. Do not use a general gauge manifold since it cannot measure a
vacuum of 650Pa.
Vacuuming
Vacuum pump with check valve
A vacuum pump with a check valve is required to prevent the vacuum pump oil from flowing back into the refrigerant
circuit when the vacuum pump power is turned off (power failure). It is also possible to attach a check valve to the actual
vacuum pump afterwards.
Standard degree of vacuum for the vacuum pump
Use a pump which reaches 65Pa or below after 5 minutes of operation.
In addition, be sure to use a vacuum pump that has been properly maintained and oiled using the specified oil. If the
vacuum pump is not properly maintained, the degree of vacuum may be too low.
Evacuating time
Evacuate the equipment for 1 hour after 650Pa has been reached.
After envacuating, leave the equipment for 1 hour and make sure the that vacuum is not lost.
Operating procedure when the vacuum pump is stopped
In order to prevent a backflow of the vacuum pump oil, open the relief valve on the vacuum pump side or loosen the
charge hose to drawn in air before stopping operation.The same operating procedure should be used when using a
vacuum pump with a check valve.
1.
2.
3.
4.
5.
1.
2.
3.
1.
2.
R32
is a pseudo-azeotropic refrigerant (boiling point R32= -52 C, R125= -49 C) and can roughly be handled in the same
way as
R410A
; however, be sure to fill the refrigerant from the liquid side, for doing so from the gas side will somewhat
change the composition of the refrigerant in the cylinder.
Charging Refrigerant
R must be in a liquid state when charging.
Reasons:
Note
In the case of a cylinder with a syphon, liquid R32 is charged without turning the cylinder up side down. Check the type
of cylinder before charging.
When refrigerant leaks, additional refrigerant may be charged. (Add the refrigerant from the liquid side)
Remedies to be taken in case of a refrigerant leak
