5.4 Installation for the first time 
Air and moisture in the refrigerant system have 
undesirable effects as below:   
●  Pressure in the system rises. 
●  Operating current rises. 
●  Cooling or heating efficiency drops. 
●  Moisture  in  the  refrigerant  circuit  may 
freeze and block capillary tubing. 
●  Water may lead to corrosion of parts in the 
refrigerant system. 
Therefore, the indoor units  and  the pipes 
between indoor and outdoor units must be leak 
tested  and  evacuated  to  remove  gas  and 
moisture from the system. 
Gas leak check (Soap water method): 
Apply  soap  water  or  a  liquid  neutral 
detergent  on  the  indoor  unit  connections  or 
outdoor  unit  connections  by  a  soft  brush  to 
check for  leakage  of the  connecting  points of 
the piping. If bubbles come out, the pipes have 
leakage. 
1. Air purging with vacuum pump 
 
1)  Completely  tighten  the  flare  nuts  of  the 
indoor and outdoor units, confirm that both 
the 2-way and 3-way valves are set to the 
closed position. 
2)  Connect the charge hose with the push pin 
of handle lo to the 3-way valves gas service 
port.. 
3)  Connect  the  charge  hose  of  handle  hi 
connection to the vacuum pump. 
4)  Fully  open  the  handle  Lo  of  the  manifold 
valve. 
5)  Operate the vacuum pump to evacuate.   
6)  Make evacuation for 30 minutes and check 
whether  the  compound  meter  indicates 
-0.1Mpa.  If the  meter  does  not  indicate 
-0.1Mpa  after  pumping  30  minutes,  it 
should be pumped 20 minutes more. If the 
pressure  can’t  achieve  -0.1Mpa  after 
pumping 50 minutes, please check if there 
are some leakage points. 
Fully close the handle Lo valve of the manifold 
valve  and  stop  the  operation  of  the  vacuum 
pump. Confirm that the gauge needle does not 
move (approximately 5 minutes after turning off 
the vacuum pump). 
7)  Turn the flare nut of the 3-way valves about 
45°  counterclockwise  for  6  or  7seconds 
after the gas 
coming  out,  then  tighten  the  flare  nut  again. 
Make sure the pressure display in the pressure 
indicator is a little higher than the atmosphere 
pressure. Then remove the charge hose from 
the 3 way valve. 
8)  Fully open the 2 way valve and 3 way valve 
and securely tighten the cap of the 3 way 
valve. 
2. Air purging by refrigerant 
 
Procedure: 
1). Confirm that both the 2-way and 3-way valves 
are set to the closed position. 
2).  Connect  the  charge  set  and  a  charging 
cylinder to the service port of the 3-way valve.   
3). Air purging. 
Open the valves on the charging cylinder and the