Haier 1U71S2SG1FA Service Manual page 184

Vacuuming
1.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.
2.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.
3.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.
4.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.
5.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.
Charging Refrigerant
R must be in a liquid state when charging.
Reasons:
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.
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.
Remedies to be taken in case of a refrigerant leak
When refrigerant leaks, additional refrigerant may be charged. (Add the refrigerant from the liquid side)
Characteristics of the Conventional and the New Refrigerants
• 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.
Accessories
Accessories Supplied with the Outdoor Unit
No.
1
2
3
Drawing
Drainage Elbow
Rubber Cushion
181
Name of Parts
Clap
Quantity
2
4
3