LG HMC030KD1 Service Manual - Page 34

4.

AIR

PURGING

1)

Air

purging

Air

and

moisture

remaining

in

the

refrigerant

system

have

undesirable

effects

as

indicated

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

refrig-

eration

system.

Therefore,

the

indoor

unit

and

tubing

between

the

indoor

and

outdoor

unit

must

be

leak

tested

and

evacuated

to

remove

any

noncondensables

and

moisture

from

the

system.

2)

Air

purging

with

vacuum

pump

1.

Preparation

■

Check

that

each

tube(both

liquid

and

gas

side

tubes)

between

the

indoor

and

outdoor

units

have

been

properly

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.

2.

Leak

test

■

Connect

the

manifold

valve(with

pressure

gauges)

and

dry

nitrogen

gas

cylinder

to

this

service

port

with

charge

hoses.

A

CAUTION

Be

sure

to

use

a

manifold

valve

for

air

purging.

If

it

is

not

available,

use

a

stop

valve

for

this

purpose.

The

"Hi"

knob

of

the

manifold

valve

must

always

be

kept

close.

■

Pressurize

the

system

to

no

more

than

150

P.S.I.G

with

dry

nitrogen

gas

and

close

the

cylinder

valve

when

the

gauge

reading

reached

150

P.S.I.G.

Next,

test

for

leaks

with

liquid

soap.

A\

CAUTION

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.

-

34

-

•

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.

Indoor

unit

30K

Outdoor

unit

Manifold

valve

Pressure

gauge

Charge

hos

Nitrogen

gas

cylinder(in

vertical

standing

position)

LG HMC030KD1 Service Manual - Page 34

Purging

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