air condition DATSUN PICK-UP 1977 Service Manual

OUTLINE
OF
AIR
CONDITIONER

REFRIGERATION

SYSTEM

CONDENSER

COMPRESSOR

RECEIVER
DRYER

COOLING
UNIT

ELECTRICAL
CIRCUIT

OUTLINE
OF
AIR

CONDITIONER

The

air
conditioner
consists

es

sentially
of
a

cooling
unit

compressor

condenser
receiver

dryer
and

piping

The

cooling
unit

secured
with

three

brackets
is
a

ttached
to
the

location

occupied
by
the

package

tray

in
the
dash

panel

The

cooled
air
from
the
duct

is

directed
into
the

passenger
compart
Air

Conditioning

DESCRIPTION

CONTENTS

AC
2

AC3

AC
3

AC3

AC4

AC4

AC
5
DESCRIPTION

MAIN

RELAY

FAN
SWITCH

THERMO

SWITCH

PRESSURE
SWITCH

COMPRESSOR
RELAY

F
I
C
D

SOLENOID
VALVE
AC
5

AC
7

AC
7

AC
7

AC
7

AC
7

AC
7

ment

through
the
three

outlets
at

the

instrument

panel

The

compressor
serves
to

compress

the

vaporized
refrigerant
and
is
attach

ed

through
the
bracket
to
the
loca

tion

occupied
by
the

mechanical
fuel

pump
on
the

engine

The
condenser
cools
the

compres

sed

refrigerant
vapor
sent

by
the
com

pressor
and
is

located
on

the
front
of
the
radiator
in

the

engine
compart

ment

The
receiver

dryer

serving
as
a

reservoir

for

storage
of
the

liquid
sent

by
the
condenser
is

located
on
the

right
in
the

engine
compartment

The

piping
consists
of

two
flexible

hoses

and
five

copper
tubes
which

connect
various

components
of
the

air

conditioning
system

I

Cooling
unit

2

Expansion
valve

3
Receiver

dryer

4

Comressor
5

Condenser

6
Duct

@
Flexible
hose

@
Copper
tube

AC
2
AC724

Fig
AC
1

Cooling
system

REFRIGERATION

SYSTEM

If

you
were
to

paint
your
finger

with
alcohol

your
finger
would
feel

cold
This
is
because
the

liquid
alcohol

takes
heat

away
from

your
finger

while
it

evaporates
If
a

quickly
evapo

rating

liquid
such
as
alcoliol
is

placed

in
a
container
inside
a
box
the
tem

f

Outside
air

U

Condenser

J6G1
i
i

1
1

t1

1

ilill
I
I

J

JJ
LlJ
i
l

7

U

Receiver

dryer

h

w

t

CONDENSER

The
condenser
is
installed
to
the

front
of
the
radiator

The
heated
and

compressed

refrigerant
gas
from
the
Air

Conditioning

perature
inside
the
box
will

drop
This

is
because
the

alcohol
is

evaporated

absorbing
the
heat
from
the
air

insidc

the
box
If
the

gaseous
alcohol
is

collected
and

cooled
with

cold
water

it
will
be

changed
back

into
a

liquid
by

absorption
of
its
heat

by
the
cold

water

The
cooler

operates
on
this

princi

Compressor

t

q
ttLJ

IrJ

Evaporator
It

J

1

J

f
9

d

lUr

I

Expansion
valve
V7777
J
High
pressure

lLLLLL
l

gas

I
I
High
pressure

liquid

t

u

compressor
condenses
to
a

liquid
by

being
cooled

by
air

passing
between

the
fins
of
the
condenser

1
GJ
7

vlmnn

iii

plI

d1i
1il

Ac459

Fig
AC

3
Condenser

AC3
pIe
The

liquid
used

is
the

refrigerant

R
12

The
heat
inside
the

passenger

compartment
is
absorbed

by

changing

the

refrigerant
from
a

liquid
to
a

gas

and
then

dissipated
to
the

outside

by

changing
the

refrigerant
from

a

gas

back
to
a

liquid

The

refrigeration
system
is

shown

in

Figure
AC
2

Low

pressurt

liquid

1

I
L2
Low

pressure

gas

Inside
air

li

r

L

Blower
motor

AC458

Fig
AC
2

Refrigeration
cycle

COMPRESSOR

The

compressor
is
installed
to
the

side

of
the

engine
and
is
driven

by

crank

pulley
through
a
belt
The

refrig

erant

gas
leaving
the

evaporator
is

forced
out
to
the
condenser

by
com

pressor
and
the
low

pressure
refrig

erant

gas
is

compressed
to
a

high

pressure
and

high

temperature

The

driving
force
is
transmitted

by

an
electrical
clutch
Because

engine

rpm
is

very
low

during
idling
the

clutch
will

not
transmit

the

driving

force
thus

ensuring
smooth

engine

idling

Air

Conditioning

RECEIVER
DRYER

The
receiver

dryer
serves
the

pur

pose
of

storing
the

liquid
refrigerant

The

amount
of
the

liquid
refrigerant

flowing
through
the

system
varies

with

the

operating
condition
of
the
air

conditioner
To
be
accurate
the

receiver

dryer
stores

excess
amount
of

refrigerant
when

the
heat
load
is

lowered
It

also
releases
stored

refriger

ant
when

additional

cooling
is
needed

thus

maintaining
the

optimum
flow
of

refrigerant
within
the

system

The
receiver

dryer
includes

a

strainer
and
desiccant

They
have
the

job
of

removing
moisture
and

foreign

particles
as
the

refrigerant
circulates

within
the

system

The

pressure
switch

is
installed

beside

sight
glass
of
receiver

dryer
The

purpose
of
the
switch

is
to

stop
the

compressor
operation
in
the
event

an

excessive

system

pressure
builds

up
on

the

high
pressure
lines
AC728

Fig
A
C
4

Compressor

To
e

ran
ion
alve

From
condenser

5

c
FJi

i

1

Z

i

3

c

o

I

COOLING
UNIT
o

L

o

W
7
R
o
3

J
J
r

t

AC230
I

Prc
surc
switch

2

Sight
glass

3
Strainer

4
De
kcant

Fig
AC
5
Receiver

dryer

The

liquid
refrigerant
evaporates
in

the

evaporator
with

the
aid
of
the

expansion
valve

Consequently
the
air

drawn

by
the
blower
motor
is

cooled

in

passing
through
the

evaporator

The

expansion
valve
restricts

the

liquid
refrigerant
as
it

passes
through
it

and

delivers

sprayed
refrigerant
to
the

evaporator
for

facilitating
refrigerant

evaporation
The

cooling
unit

includes
an

evapo

rator
and
an

expansion
valve
From

the
electrical

point
of
view

the

cooling
unit
consists
of
a

blower

motor

a
resistor
for
fan

speed
control

and
some
switches
and

relays

AC
4

The

refrigerant
within
the

thermo

bulb

changes
in

pressure
through
the

super
heat

condition
of

vaporized
re

frigerant
gas
which
comes
out
of
the

evaporator
causing
the

deflection
of

the

diaphragm
The
lift

of
the

ball

valve
attached
to
the

diaphragm
is

changed
by
the
deflection
of
the
dia

phragm
thus

controlling
the
amount

of

refrigerant
passing
the

orifice

ELECTRICAL
CIRCUIT

DESCRIPTION

The

electrical
circuit

of
the
air

conditioner
consists
of
four
switches

two

relays
a
solenoid
valve
a
fan

motor
and
a

compressor
magnetic

clutch
Air

Conditioning

Diaphragm

Orifice

Valve
ball

AC729
4

Sensing
bulb

Fig
A
C
6

Expansion
value

The

following
wiring
diagram

pro

vides
a

complete
description
of
the

whole
circuit

When
the

ignition
switch
and
the

fan
switch
are
ON
the
main

relay
is

activated

causing
battery
power
to

flow

through
the
fan
motor
and
the

magnetic
clutch
The

magnetic
clutch

is

activated

by
the
thermo
switch

AC
5
000

l

1
Motor

2
Fan

3
Lower

case

4

Cooler
duct

5

Evaporator

6

Expansion
valve

7

Upper
case
8
Resistor

9

Main

relay

10
Thermo
switch

II
Cable

clamp

12

Cable

13
Harness

AC725

Fig
AC
7

Cooling
unit

pressure
switch
and

compressor
relay

The

blower
motor
fan

speed
is

con

trolled

by
the
fan
switch
and
resistor

The
solenoid
valve
is

also
activated

This
in
turn

causes
the

fast
idle
control

device
F
l

C
D
to
increase

engine

speed
when
the

vehicle
is

at
rest
with

the

engine
ON

1
I

6

I

BA

RY

i
Air

Conditioning

BW
c
J

BW

n
B

m

00
L
ELECTRIC

FUEL
PUMP

oB

tl

b@

L

t

FROM
LIGHT

SWITCH

c
J

LW
2
L

rRL
fZP
W

I
FUSE
15A

J
D
CJ
B

1
COMPRESSOR
RELAY
B

GL
I

lL

GL1J
ILLUMINATION

CONTROL

RHEOSTAT

3

ILLUMINATION

LAMP

I

I
MAIN
RELAY

FAN
SWITCH

I

r

1

UE
H

I

I
THERMO

SWITCH

COLOR

CODE

@

IC
PRESSU
1

rlTCH

D
D

G
c
J
oc

I
m

f
F
I
C
D

SOLENOID

COMPRESSOR

FUSE
LR

I

BW
O

W

ov
J

I

IG
0

0

OVJ

AC

6
B

BW

L

LW

LR

W

G

GL

RL
Black

Black
with
white

stripe

Blue

Blue
with

white

stripe

Blue
with
red

stripe

White

Green

Green
with

blue

stripe

Red
with
blue

stripe

IG

BW
t
1

n

L

IGNITION
SWITCH

AC727

Fig
A
C
B

Wiring
diagram
of
air
conditioner

system

MAIN
RELAY

The
main

relay
is
located
on
the

cooling
unit

When
the

ignition
switch
and
fan

switch

are
both
turned
on
the

COll

@

FAN
SWITCH

The

fan
switch

serving
as
a
control

unit
is

installed
on
the
center
console

This
switch

controls
the

blower
motor

speed
through
the
resistor
It
is
also

used
as
a

main

relay
switch

Fig
AC
I0
Fan
switch

THERMO

SWITCH

The
thermo

switch
is

located
on
the

upper
side
of
the

cooling
unit
and
is

controlled

by
the

cable
and
the
con

trollever
attached
to
the
console
box

It
is
so

designed
that
when
the
air

passing

through
the

evaporator
core
is

cooled
down

to
the

predetermined
Air

Conditioning

tacts
in
the

relay
are
closed
Then

electrical

power
from
the

battery
is

supplied
to
the
blower

motor
and
the

electrical
clutch
for
the

compressor

@

Dc

IDe

ID
1
1

l@

@
e

L
J

AC465

Fig
A
C
9
Main

relay

temperature
set

by
the

control
lever

it

automatically
turns

off
When
the

switch
is
turned
off
the

magnetic

clutch
is

turned
off

stopping
the
flow

of

refrigerant
inside
the

cooling
system

and

increasing
the

cooling
system
tem

perature

When
the

air
rises
to
the

pre

determined

temperature
the
thermo

switch

automatically
turns

on
In
this

way
the

temperature
of
the
air
dis

charged
from
the

cooling
unit
is
auto

matically
controlled
as
desired

PRESSURE

SWITCH

The

pressure
switch
is
turned
off

when

refrigerant
pressure
in
the

cooling
system
rises
to

an

abnormally

high
level
28

kg
cm2

398

psi
This

in

turn
turns
off
the

compressor

magnetic
clutch

actuating
the
com

pressor
relay
and

gradually
decreasing

pressure
in
the

cooling
system
When

the

pressure
drops
to
or
below
24

kg
cm2
341

psi
the

pressure
switch

again
turns
on

Thus

cooling

system
refrigerant

pressure
is

automatically
maintained
at

the

proper
value

a
t
all
times

AC
7
COMPRESSOR
RERAY

The

compressor
relay
is

attached
to

the
receiver

dryer
bracket
on
the

right

side

of
the

engine
compartment
This

relay
is

actuated
by
the

fan
switch

thermo
switch

and

pressure
switch
to

turn
on

and
off
the

compressor

magnetic
clutch

cv

1

2

AC731

Fig
A
C

11
Pressure
switch
and

compressor
relay

F
I
C
D
SOLENOID
VALVE

The
F
l
C
D
solenoid

valve
is
at

tached
to
the
dash

panel
in
the

engine

compartment
This
valve

supplies
vacu

um
to
the

F
I

C
D

diaphragm
through

the
vacuum
hose
connected

to
the

engine
intake
manifold
when
the

engine
is

at
idle
and

the

cooling
system

is
ON

thereby
raising
idle

speed
to
the

predetermined
rpm
800

IW

r

e

I

1
s

AC132

Fig
AC
12
F
l
C
D
solenoid

value

REFRIGERAi
H
R
12

COMPRESSOR
OIL

MAINTENANCE

PERIODIC
MAINTENANCE
AND

SEASON
IN

INSPECTION

GENERAL
SERVICE
INSTRUCTION

SAFETY

PRECAUTIONS

EV

ACUA
TlNG
AND

CHARGING
SYSTEM

HANDLING

MANIFOLD
GAUGE

HANDLING
SERVICE
VALVE

HANDLING
CAN
TAP

DISCHARGING
SYSTEM

REFRIGERANT
R
12

The

refrigerant
used
in
the
air

conditioner
is

generally
called
Re

frigerant
12

R
12
No
other

refrig

erant
than
the

above

refrigerant
should

be
used

This

refrigerant
is

usually
available

in
a
small
can
or
a

cylinder
In

either

case
it

is

liquefied
under

high
pressure

in
the
container

Refrigerant

evaporates
easily
has
a

low

evaporation
point
and
moreover

since
the
latent

heat
of
the

refrigerant

is

large
it

can
abSorb

a

large
amount

of
heat

wh

err
e

vaporating
Extreme

care
must
be
exercised
when

handling

the

refrigerant

COMPRESSOR
OIL

The
SUNISO
5GS
or
SUNISO

351

should
be
used
as

refrigeration

lubricant

Mixing
of
the

two
is

allowable

The

refrigeration
lubricant
should

be
used
to
assure
the
successful
com

pressor
operation
Use
of
oils
other

than
recommended
or

mixing
of
the

oil

with
other
oils
would
cause

chemical
reaction

or
lead
to
lowered

viscosity
or
deficient
lubrication

The
oil

absorbs
moisture
as
it

con

tacts

the
air
This

points
out
the
need

for

care
not
to

expose
it

to
atmos

phere
for
an

extended

period
of
time
Air

Conditioning

GENERAL
SERVICE

CONTENTS

EVACUATING
SYSTEM

CHARGING
REFRIGERANT

CHECKING
FOR
LEAKS

HALIDE
LEAK

DETECTOR

ELECTRIC
LEAK

DETECTOR

REFRIGERANT
LEVEL
CHECK

SIGHT

GLASS

PERFORMANCE
TEST

COMPRESSOR
OIL
LEVEL
CHECK

PERFORMANCE
TEST

REFRIGERANT

LEAKS
AC
8

AC

8

AC
8

AC
8

AC
8

AC
9

AC
9

AC
9

AC10

AC

11

AC
12

MAINTENANCE

PERIODIC
MAINTENANCE

AND

SEASON
IN

INSPECTION

Both

periodic
maintenance
and

season
in

inspection
are

most
essential

to
enable
the
air

conditioner
to

give

full

performance

Perform
the

following
checks

Start

engine
and

check

refrigerant

level

through
sight
glass
on

receiver

dryer
For

details
refer
to

relative

topics
under

Refrigerant
Level

Check

2
Check
the
entire

sysiein
for

sign

of

refrigerant
leaks

Refer
to
relative

topics
under

Checking
for

Leaks

and

Refrigerant
Leaks

If

any
trace
of
oil
is

noted
at

and

around
connection

fittings
it
is
a

sure

indication

that

refrigerant
is

leaking

This
condition

can
be
corrected

easily

by
retightening
the

joints
If

any
joint

on
line

is

suspected
of
small
amount
of

leakage
use
a
leak

detector
to

locate

leaking
points

3
Check

compressor
drive
belts

for

proper
deflection

Season
off

Observe
the

following
maintenance

tips
to
allow

the
air

conditioner

to

operate

normally
in

the
next

season

I

Keep
the
entire

system
free
from

AC
8
AC12

AC

13

AC15

AC15

AC16

AC

16

AC16

AC
17

AC17

AC
17

AC18

refrigerant
leakage
by

periodically

checking
for

refrigerant
gas
leak

even

out
of
season

2

Turn
the

compressor
for
10

minutes

at
least
once
a
month

by

running
the

engine
at
1

500

rpm

c
ENERAL
SERVICE

INSTRUCTION

The

servicing
of
the
air
conditioner

should
be
carried
out

only
by
well

trained
servicemen
This

chapter
de

scribes
essential

points
of

servicing

Jf

a

Jarge
amount
of

dirt
and
sand

enter

the

system
they
will
be

carried
with

refrigerant
and

may

clog
the

system
or
scratch

rotating

parts
This

points
out
the
need
for

care
in

servicing
the

system
That

is

disconnecting

joints
should
be

carried
out

in
a
dean

place

Water
should
not
be
allowed
to

get

inside
the

system
The

refrigerant

does
not

readily
mix

with
water

However
the

presence
of
even
a

minute

amount
of

water
will
cause

a
chemical
reaction

at

high
tem

perature
which
will
in

turn

produce

hydrochloric
acid

HCl
Since

hydrochloric
acid
is

highly
corro

sive
to
metals
the
aluminum
and

copper
piping
etc
will
become

corroded
and
the

refrigeration

system
will
become

clogged

Water
in
the

system
will

ice
the

orifice
when
the

high
pressure
re

frigerant
is

changed
to
low

pressure

refrigerant
by

expansion
valve
etc

and
will
obstruct
the

refrigerant

flow

The

following
items

are

general

instructions
to
be

closely
observed
in

servicing
the

system

I
When
a

system
line
is

discon

nected

plug
the

opening
immediately

This
is

especially
necessary
to

prevent

moisture

condensation
from

forming

in
the
line
and
to

keep
out
dirt
and

dust
It
is
also

necessary
to

keep
the

line
at
and
above

surrounding
air

temperatures
at
all

times
When

con

necting
system
lines
do

not

attempt

to
remove
the

plug
from
the

opening

until

ready
for
immediate
use

2

Always
keep
the

working
place

clean
and

dry
and
free
from
dirt
and

dust

Wipe
water
off
with
a
clean

cloth

3
Have
all

necessary
tools
in

pre

paration
beforehand

and
have

tools

clean
and

dry

4
The

compressor
oil
will

easily

absorb
moisture
when

exposed
to
air

Immediateiy
close
the

opening
of
the

container
after
use
It
is
also

necessary

to
observe
the

following
notes

Notes

a
The
oil
should
not
be
transfused

from
a
container
into

another
as

the
failure

will

possibly
cause
mois

ture
to
mix

with
the
oil

b
The

used
oil
should
not
be

returned

into
a
container

c

The
oil

should
not

be
used
if
its

state
of

preservation
is

not
clear

enough

5
When

connecting
or

disconnect

ing
pipes
from
the

refrigeration
sys

tem
use
two

wrenches
One
wrench
is

used
for

holding
the

fixing
nut

in

place

while
the

other
for

turning
the

mating

flare

nut
Failure
to
do

so

may
result

in
a

twisted
tube
or

may
damage

connection

6
Also
use
care
not
to

give
scratches

to
the

seating
surface
at
connections

A

small
scratch
on

the

seating
surface
Air

Conditioning

may
be
the
cause
of

gas
leakage

Before

connecting
pipes
be
sure
to

give
coating
of

compressor
oil
to
the

sea

ting
surfaces

SAFETY

PRECAUTIONS

I

Since
direct

contact
of
the

liquid

refrigerant
with

your
skin
will
cause

frostbite

always
be
careful

when

handling
the

refrigerant
Wear

gloves

or

wrap
a

piece
of
cloth
around
service

valve

to

protect
your
fingers
against

frostbite

by

refrigerant
If

any
of
the

refrigerant
should

get
into

your
eyes

when

charging
the

refrigerant
splash

your
eyes
with

cool
water
to
raise

the

temperature
gradually
Apply
a

protec

tive

film
to

the

eye
to

avoid
infection

Do
not
rub

your
eyes
Consult
an

eye

specialist
Always
wear

goggles
or

glasses
to

protect
your
eyes
when

working
around
the

system
Should

refrigerant
strikes

your
body
splash

on
cool
water
and

apply
a

protective

film

2
The

refrigerant
service
container

has
a

safe

strength
However
if
han

dled

incorrectiy
it
wili

explode

Therefore

always
follow
the
instruc

tions
on
the

label
In

particular
never

stpre
it
in

a
hot

location
above

S20C

l250F
or

drop
it
from

a

high

height

3
The

refrigerant
gas
is

odorless
and

colorless
and

breathing
may
become

difficult

due
to
the

lack
of

oxygen

Since
the

refrigerant
gas
is

heavier
than

air
and

will

lay
close
to
the
floor
be

especially
careful
when

handling
it

in

small

confined

spaces

4

The

refrigerant
itself
is
nonflam

mable
However
a

toxic

gas

phosgene

gas
is

produced
when
it

contacts
fire

and

special
care
is
therefore

required

when

checking
for

leaks
in

the

system

with

a
halide
torch

5

Do
not
steam

clean
on
the

sys

tern

especially
condenser
since
exces

sively
high
pressure
will
build

up
in

the

system
resulting
in

explosion
of
the

system

The

above

precautions
are
essential

in

handling
of

Refrigerant
l
2
and

their
strict
observation

requires
suffi

AC
9
dent

training
Therefore
it
is

of
first

importance
that

any
other

personnel

than
a
well
trained
serviceman
should

not
be

allowed
to
handle
the

refrig

erant

EVACUATING

AND

CHARGING
SYSTEM

During

servicing
use
caution
to

keep
air

from

getting
into

refrigerant

When
air

enters
the

system
all

refriger

ant

must
be
evacuated
from

system

prior
to

charging
new
refrigerant
Air

in

refrigerant
has
the

following
delete

rious

effects

I

Since
the
condensation

tempera

ture

of
the
air
is

extremely
low
the
air

will

not
be

condensed
when

refrigerant

gas
is
condensed

in
the
condenser
and

the

air
will

thus
remain
in

gaseous

form

Consequently
the
effective

thermal

transmission
area

of
condenser

for

refrigerant
gas
will
be
red
uced
and

refrigerant
gas
to
be
condensed
will
be

red
ueed
The

pressure
rise
will
become

proportional
to

the
volume
of
the
air

in

system

2

When
air
and

refrigerant
are

mixed
in

system
a
chemical
reaction

will
be

produced
and

hydrochloric

acid
which
will

adversely
affect
the

aluminum

copper
iron
and
other

materials
in

system
may
be

generated

HANDLING
MANIFOLD

GAUGE

The

pressure
at
the

high
and
low

sides
of

system
should
be

measured

when

evacuating
and

charging
refrig

erant
and
when

diagnosing
trouble
in

the

system
The
manifold

gauge
is
used

for
these

purposes
A

manifold

gauge

has
two

pressure
gauges
a

low

pressure

gauge
and
a

high
pressure
gauge
These

gauges
are

connected
to

the

high
and

low

side
service

valves
of

system

through
flexible

charging
hoses

The

construction

of
manifold

gauge
is

shown
in

Figure
AC
13

When
valve
stem
is

fully
screwed

the
valve
is
front
seated
and
valve

path

and
the
center

path
are
blocked
When

valve
stem
is

backed
off
the

paths
are

opened

Air
Conditioning

Low

pressure
gauge

Compound
pres
lIrt

gaug
High
rHe
ure

g
Uge

c

7

I

Back
se
ted

Full
counter

J

clockwise

Ji

r

rnF
r

r1
gL

r

W
t

g

2

Connection
to
service
valve

I

Fully
close
both
valves
of
mani

fold

gauge
Connect
high
and
low

pressure
charging
hoses
to
manifold

gauge

2
Remove

caps
from
service
valves

Connect
high
and
low

pressure
charg

ing
hoses
to
service
valves
in

system

The

refrigerant
gas
wili
be

discharged

since
check
valve
is

open
when

pressing
charging
hose
onto

service

valve

3

Next
loosen
the

connection
fit

ting
of

charging
hose
at
manifold

gauge
side
for
2

to
3
seconds
to

purge

any
air

inside

charging
hose

by
the

pressurized
gas
in

system

Disconnedion
from

service
val
v

I

Fully
close
both
valves
of
mani

fold

gauge

2

Disconnect
two

charging
hoses

from
service
valves
At

this
time
the

gas
will
be

discharged
until
check
valve

is
closed
Therefore
disconnect
hose

quickly

Caution
Work
with

fingers
protected

with
cloth

against
frostbite

by
re

fri
l
fant
To
low
side
To
vacuum

pump
OI

To

high
ide

rvicc
valve

refrigerant
can

service
va
lve

HANDLING
SERVICE
VALVE

An
automatic
check
valve
is
built

into

service
valve
When
this
valve

presses
against
the
connection

fitting

that
is
when

charging
hose

is
con

nected
to
service
valve
the
valve
is

open
When

charging
hose
is
discon

nected
the
valve
is
closed
automatical

ly
Always
observe
the

following
usage

precautions

Always
install
valve

cap
after

using
service
valve

When

high
speed
opera
tion
is

per

formed
without
valve

cap
a

negative

pressure
will

gradually
build

up
at

the

low

pressure
side
of

system
and
air

may
be
sucked
in
In
addition
dirt
and

dust

will

easily
enter
the
valve
result

ing
in
foreign
matter

entering
the

system

L

5V

j

Close

AC
l0
Front
seated

Full
clockwise

AC243

Fig
AC
13

Manifold
gauge

2
Check
valve
will
be
half

opened

during
connection
and
disconnection

of

charging
hoses
and

refrigerant
will

be
forcefully

discharged
Therefore

connect
and
disconnect

charging
hoses

quickly
while

pressing
flare
nut

of

charging
hose

against
service

valve

Caution
Work
with

fingers
protected

with
cloth

against
frostbite

by
re

frigerant

3

Since
close
contact
between
the

thread
of
valve

eap
and

the
thread
of

service

valve
will

prevent
gas
leakage

keep
these
sections
clean
and
free
of

scratches
and
damage

4

Since

packing
of

charging
hose

will
be

lost

during
long
use

always

check

packing
prior
to

installing
charg

ing
hose

J

17

t

1
1

t

Cap

2

Service
valve

3

Charging
hose

AC733

Open

Fig
AC
14
Service
oolve

b

r
r

AC734

Fig
A
C

15
Service
value

docK
wise

n

r
Air

Conditioning

HANDLING
CAN
TAP

A

wide

variety
of
can

taps
are

available
The

following
procedures

apply
to

conventional

can

taps

For
the

correct

usage
refer
to

the

manufacturer
s

instructions

Caution
Use

can

tap
of

good
quality

I
Connect

charging
hose
to
the

center
fitting
of
manifold

gauge
At

this
time
confirm
that
both
stems
are

fully
turned
in

front
seated

2
Turn

can

tap
handle

fully
coun

Counterclockwise

s

r

@

A

rn

Purging
air

n

R
I2

AC
terclockwise

so
that
the

needle
is

pulled

up

3
Attach

can

tap
to

refrigerant
can

firmly

4

Turn

can

tap
handle

fully
clock

wise
to

make
a

hole
in

refrigerant

can

5

Turn
the
handle

fully
counter

clockwise
to
raise
the

needle

Refriger

ant

gas
will

flow

up
to
the
center

fitting
of

manifold

gauge

6
Loosen
the

connection
a
t

the

center

fitting
of
manifold

gauge
for
a

few
seconds
to

purge
air

inside

charg

ing
hose
See

Figure
AC
16

1
Can
tap
handle

2

Charging
hose

3
Needle

4

Refrigeran
t
can

AC246

AC247

Fig
AC
16
Can

tap
and

pw
ging
air

q