15 
 
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 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). Open the valves (Low side) on the charge set 
and charge the system with liquid refrigerant 
If the system cannot be charge with the specified 
amount  of  refrigerant,  or  can  be  charged  with  a 
little  at  a  time  (approximately  150g  each  time)  , 
operating the air conditioner in the cooling cycle; 
however,  one  time  is  not  sufficient,  wait 
approximately  1  minute  and  then  repeat  the 
procedure. 
5).When the  electronic  scale displays the  proper 
weight,  disconnect  the  charge  hose  from  the  3-
way valve’s service port immediately 
If  the  system  has  been  charged  with  liquid 
refrigerant while operating the air conditioner, turn 
off  the  air  conditioner  before  disconnecting  the 
hose. 
6). Mounted the valve stem caps and the service 
port.  Use  torque  wrench  to  tighten  the  service 
port cap to a torque of 18N·m (13.27 ft·lbs).  
Always  leak  check  after  servicing  the  refrigerant 
system. 
 
For  M3OF-27HFN1-M/M4OF-36HFN1-M/M5OF-
48HFN1-M 
There are one low-pressure centralized valve and 
one  high-pressure  centralized  valve,  it  will  be 
more  time  saving  when  vacuum  and  recycle 
refrigerant.  But  refer  to  the  previous  instruction 
when vacuum and recycle refrigerant.