charge set. Purge the air by loosening the flare 
nut  on  the  2-way  valve  approximately  45’  for  3 
seconds  then  closing  it  for  1  minute;  repeat  3 
times. 
After  purging  the  air,  use  a  torque  wrench  to 
tighten the flare nut on the 2-way valve. 
4). Check the gas leakage. 
Check the flare connections for gas leakage. 
5). Discharge the refrigerant. 
Close  the  valve  on  the  charging  cylinder  and 
discharge  the  refrigerant  by  loosening  the  flare 
nut on the 2-way valve approximately 45’ until the 
gauge indicates 0.3 to 0.5 Mpa. 
6). Disconnect the  charge set  and  the charging 
cylinder, and set the 2-way and 3-way valves to 
the open position. 
Be sure to use a hexagonal wrench to operate the 
valve stems. 
7). Mount the valve stems nuts and the service 
port cap. 
Be  sure  to  use  a  torque  wrench  to  tighten  the 
service port cap to a torque 18N·m. 
Be sure to check the gas leakage. 
3.  Adding  the  refrigerant  if  the  pipe 
length >5m   
 
Procedure: 
1).  Connect  the  charge  hose  to  the  charging 
cylinder,  open  the  2-way  valve  and  the  3-way 
valve. 
Connect  the  charge  hose  which  you 
disconnected  from  the  vacuum  pump  to  the 
valve  at  the  bottom  of  the  cylinder.  If  the 
refrigerant is R410A, make the cylinder bottom 
up to ensure the liquid charge. 
2). Purge the air from the charge hose. 
Open  the  valve  at  the  bottom  of  the  cylinder 
and press the check valve on the charge set to 
purge  the  air  (be  careful  of  the  liquid 
refrigerant). 
3) Put the charging cylinder onto the electronic 
scale and record the weight. 
4)  Operate  the  air  conditioner  at  the  cooling 
mode. 
5) Open the valves (Low side) on the charge set 
and charge the system with liquid refrigerant. 
6).When the electronic scale displays the proper 
weight (refer to the table), disconnect the charge 
hose  from  the  3-way  valve’s  service  port 
immediately and turn off the air conditioner before 
disconnecting the hose. 
7).  Mount  the  valve  stem  caps  and  the  service 
port 
Use torque wrench to tighten the service port 
cap to a torque of 18N.m. 
Be sure to check for gas leakage. 
6.5 Adding the refrigerant after running 
the system for many years 
 
Procedure: 
1). Connect the charge hose to the 3-way service 
port, open the 2-way valve and the 3-way valve. 
Connect  the  charge  hose  to  the  valve  at  the 
bottom  of  the  cylinder.  If  the  refrigerant  is 
R410A, make the cylinder bottom up to ensure 
liquid charge. 
2). Purge the air from the charge hose. 
Open  the  valve  at  the  bottom  of  the  cylinder 
and press the check valve on the charge set to 
purge  the  air  (be  careful  of  the  liquid 
refrigerant). 
3) Put the charging cylinder onto the electronic 
scale and record the weight.