9  ADDITIONAL REFRIGERANT CHARGE
9.1  AIR-TIGHT TEST
Check  to  ensure  that  spindles  of  the  stop  valves  for  High/Low 
pressure gas, Low pressure gas and Liquid pipes are closed com-
pletely before air-tight test.
The refrigerant used for this outdoor unit is R410A.  Use the mani-
fold gauge and the charging hose for exclusive use of R410A.
 
Tightening check of stop valves
After connecting the pipe, remove the caps of stop valves for high/
low  pressure  gas,  low  pressure  gas  (for  heat  recovery  system 
only) and liquid. Tighten the open-close spindle in the closing di-
rection according to the following tightening torque.
Caution for operation of stop valves
a.  Remove the stop valve caps before performing the air-tight 
test  after  connecting  the  refrigerant  piping.    Tighten  the 
spindle (valve) in clockwise direction according to the fol-
lowing tightening torque.
b.  Perform the work after warming the spindle part with a dry-
er etc. when controlling the stop valve in a cold area. (O-
ring of the spindle part will harden at the low temperature 
and the refrigerant leakage may occur.)
c.  Do  not  apply  an  excessive  force  after  fully  opening  the 
spindle. (Tightening Torque: < 5.0N-m) (The back seat is 
not provided.)
d.  When each valve is opened, remove tags “Close” (Acces-
sories) and attach tags “Open” instead.
e.  Tighten securely the caps according to the following tight-
ening torque after each spindle valve is opened.
Stop valve for low 
pressure gas
Stop valve 
for liquid
Flare nut
Stop valve for high/low 
pressure gas
Check joint 
(Only the charging hose for 
R410A can be connected.)
Hexagonal wrench
High/Low Pressure 
     Low Pressure: 10 mm 
             Liquid: 4 mm
(To open or close spindle valve)
O-ring 
(Rubber)
Refrigerant 
pressure
Spindle valve
Closed before shipment
Counterclockwise...Open 
Clockwise...............Close
Cap
(N-m)
Outdoor unit
Spindle (Valve) Flare Nut Cap Check Joint
High/Low pressure 
and low pressure 
gas valves
Liquid 
valve
Liquid
High/low pressure 
and low pressure 
gas valves
Liquid 
valve
High/low pressure 
and low pressure 
gas valves
Liquid 
valve
5 - 12HP 18.0 - 22.0
7.0 - 9.0
33.0 - 42.0
49.0 - 58.0 33.0 - 42.0 9.0 - 14.0 14.0 - 18.0
14/16 25.0 - 31.0 50.0 - 62.0
 
Air-tight test method
Connect the manifold gauge to the check joints of the liquid line 
and the gas line stop valves using charging hoses with a vacu-
um pump or a nitrogen cylinder. Perform the air-tight test. Do not 
open the stop valves. Apply nitrogen gas pressure of 4.15MPa for 
FSXN1E and FSXNH(E) series. For checking  gas leakage, use 
the leak detector or forming agent. If there is any leakage, x the 
leaking part.
For checking gas leakage, do not use a forming agent which gen-
erates ammonia. Additionally, do NOT use a household detergent 
as forming agent whose components are not clear. The recom-
mended foaming agent for checking gas leakage is shown below.
Procedure
Completion 
of refrigerant 
piping
Applying  
nitrogen gas
Check of pressure 
decrease
Pass
Repairing of 
leakage part
Recommended forming agent Manufacturer
Guproex Yokogawa & CO.,Ltd
  DANGER
Be sure to use Nitrogen Gas for air-tight test. If other gases 
such as oxygen gas, acetylene gas or uorocarbon gas are ac-
cidentally used, it may cause an explosion or gas intoxication.
49
PMML0294A rev.2 - 07/2014
Additional refrigerant charge
PMML0294A_rev.2_02-2014.indb   49 14/07/2014   12:28:30