Lo
Hi
Indoor unit
Outdoor unit
Manifold valve
Charge hose
Nitrogen gas
cylinder(in vertical
standing position)
Pressure
gauge
Air purging
Pressure in
the system
rises.
Air
an
d m
ois
tu
re
re
ma
in
in
g in
th
e re
fri
ge
ra
nt
sy
ste
m h
av
e u
nd
es
ira
ble
eff
ec
ts
as
in
dic
ate
d
be
lo
w.
Operating current
rises.
Cooling(or heating)
efficiency
drops.
Mo
is
tu
re
in
th
e r
efr
ig
er
an
t c
ir
cu
it
ma
y
fr
ee
ze
an
d b
lo
ck
ca
pil
la
ry
tu
bin
g.
Water
may lead
to corrosion
of parts
in the
refrigeration system.
Therefore, the
indoor unit
and tubing
between
the indoor
and outdoor
unit must
be leak
tested
and evacuated to remove any non condensable
gas and moisture from the system.
Air purging
with vacuum
pump
A
Check that
each tube(both
liquid and
gas
sid
e
tu
be
s)
be
tw
ee
n
th
e
in
do
or
an
d
ou
td
oo
r
un
it
s
ha
ve
be
en
pr
op
er
ly
connected and
all wiring
for the
test run
has been
completed. Remove
the service
valve caps
from both
the gas
and the
liquid
side on
the outdoor
unit. Note
that both
the
liquid and
the gas
side service
valves on
the outdoor
unit are
kept closed
at this
stage.
B
Leak t
est
Connect the
manifold valve(with
pressure
gauges) and
dry nitrogen
gas cylinder
to
this service
port with
charge hoses.
Do a
leak test
of all
joints of
the tubing(both
indoor and
outdoor) and
both gas
and liquid
side
service valves.
Bubbles indicate
a leak.
Be sure
to wipe
off
the
soap with
a clean
cloth.
After the
system is
found to
be free
of leaks,
relieve the
nitrogen pressure
by loosening
the
charge hose
connector at
the nitrogen
cylinder.
When the
system pressure
is reduced
to normal,
disconnect the
hose from
the cylinder
.
AIR PURGING
Prepar
ation
INSTALL
ATION
To avoid nitrogen entering the refrigerant system in a
liquid state, the top of the cylinder must be higher than its
bottom when you pressurize the system. Usually, the
cylinder is used in a vertical standing position.
CAUTION
18
Be sure
to use
a manifold
valve for
air
purging. If
it is
not available,
use a
stop valve
for this
purpose. The
3-way valve
must always
be
kept close.
CAUTION
Pressurize the
system to
maximum 250
P .S.I.G.(R-22
model) or
400 P
.S.I.G.
(R-410A model)
with dry
nitrogen gas
and
close the
cylinder valve
when the
gauge
reading reached
250 P
.S.I.G. (R-22
model)
or 400
P .S.I.G.
(R-410A model).
Next, step
is leak
test with
liquid soap.
There is
a risk
of fire
and explosion.
-
Inert gas
(nitrogen) should
be used
when you
check
plumbing leaks,
cleaning or
repairs of
pipes
etc.
If
you are
using combustible
gases including
oxygen,
product may
have the
risk of
fires and
explosions.
CAUTION
