Leak Test; Vacuum Operation - Gree KM48H4O Service Manual

Caution!
 During the connection of the indoor unit and BU module to the refrigerant pipe, never pull any joints of the
indoor unit and the BU module by force; otherwise the capillary pipe or other pipe may crack, which then
would result in leakage.
 The refrigerant pipe should be supported by brackets, that is, don't let the unit withstand the weight of it.
 For the Super Free Match system, each pipe should be labeled to tell which system it belongs to avoid
mistaken inaccurate piping.

6.8 Leak Test

1) Please make sure that the stop valves of the outdoor unit are closed during the operation.
2) The leak test should be made by pressurizing nitrogen gas.
3) Turn on the Hi-knob and Lo-knob. The leak test should be done simultaneously at both the gas and
liquid stop valves.
4) Open the pressure reducing valve, pressurize the connection pipes to 1.0 MPa (10 bar) slowly, wait
fifteen minutes, and make sure that the pressure will not drop.
5) Rise the pressure to 4.0 MPa (40 bar) slowly, wait 24 hours, and make sure the pressure will not drop.
6) If the pressure does not decrease, the pipes have passed the test. Otherwise, look for where the gas leaks
from.
1: Outdoor unit
2: Liquid side stop valve
3: Gas side stop valve
4: Pressure-vacuum gauge
5: Hi-knob
6: Lo-knob
7: Pressure reducing valve
8: Nitrogen

6.9 Vacuum Operation

1) Make sure that the liquid and gas stop valve of the outdoor unit are closed fully during the operation.
2) As shown in the following figure, expel the gas from the refrigerant pipes by the vacuum pump.
3) Open the pump and turn on the knobs to evacuate the gas in the liquid and gas pipes. The vacuuming
should be done simultaneously at both the gas and liquid stop valves.
4) When the pressure of the system is less than -0.1Mpa (-1bar), keep the system for more than one hour
under the condition.
Super Free Match
Service Manual
97 INSTALLATION