Additional Refrigerant Charge; Air-Tight Test; Vacuuming - Hisense Hi-FLEXi S Series Technical, Installation, Maintenance

Additional Refrigerant Charge

6. Additional Refrigerant Charge

6.1 Air-Tight Test

(1) Check to ensure that the stop valves are closed completely before air-tight test.
(2) Connect the indoor units and the outdoor unit with field-supplied refrigerant piping.
Suspend the refrigerant piping at specified points and prevent the refrigerant piping from touching weak parts of the
building such as wall, ceiling, etc.. Vibration of the piping may give abnormal sound.
(3) Connect the manifold gauge to a vacuum pump or a nitrogen cylinder and the check joint of the liquid stop valves and
gas stop valves with charging hoses.
(4) Apply nitrogen gas pressure of 601psi(4.15MPa).
Do not open the stop valves.
Be sure to use Nitrogen Gas for air-tight test. If other gases such as oxygen gas, acetylene gas or fluorocarbon gas are
accidentally used, it may cause explosion or gas intoxication.
(5) Check for any gas leakage at the flare nut connections, or brazed parts by use of a foaming agent or gas leak detector.
(6) Mount the piping insulation materials after connecting the pipe.

6.2 Vacuuming

(1) Connect manifold gauge and vacuum pump to the check joints.
(2) Continue vacuum pumping for one to two hours until the pressure reaches -14.5Psi(-0.1MPa /-756mmHg) or lower.
After vacuum pumping, stop the valve of manifold gauge, stop the vacuum pump and leave it for one hour
Check to ensure that the pressure in the manifold gauge does not increase.
(3) Tighten the cap of check joint after vacuum pumping.
NOTES:
(1) If tools or measuring instruments come into contact with the refrigerant, use the tools or the measuring instruments
exclusively for R410A.
(2) If vacuum degree of -14.5Psi(-0.1MPa /-756mmHg) is not available, it is considered that there is a gas leakage. Check
for any gas leakage and correct. After it's correct, just go back to (2).
● Insulate the refrigerant pipes as shown in Fig.5.2. After connecting
the refrigerant piping, seal the refrigerant pipes by using the
field-supplied insulation material. Insulate the unions and flare
nuts at the piping connections completely. Insulate the liquid piping
and gas piping completely to avoid decreasing of performance and
dewing on the surface of the pipe.
Procedure
Completion of
Charging
Ref. Piping
Nitrogen Gas
Check of Pressure
Decrease
Leak Repair
100
Pass
Stop Valve
Insulation
(Field-Supplied)
Refrigerant Piping
(Field-Supplied)
Fig. 5.2 Insulation on Pipes