1979 DATSUN 210 engine

Air

Conditioning

DESCRIPTION

OUTLINE
OF
AIR

CONDITIONER
level
and

ventilation
functions
Its

control

system
consists

of
a
mechani

cal

system

using
cables
and

engine

vacuum
and
electric

system

The

component
units

of
the
air

conditioner
are
installed
in
the

engine

and

passenger
compartments
the
compressor
and
condenser
in

the
for

mer

and
the
unit

comprising
the

evaporator
heater
and
blower
and
i

Is

control
in
the

latter
The

units
in

the

passenger
compartment
aTe
summa

rized
as
foUows
Th

ipr
conditio
er
isa

combine4

unit

of
an

evaporator
heater
and

blower
and

provides
heating
and
cool

lng
functions
In

addition
it

has
hi

I

1
Heater
unit

2
Ventilation

door

3

Air
mix
dom

4

Air
intake
door

5

Cooling
unit

6
E

r
or

7
Blower
motor

8
Floor
door

AC377A

Fig
AC
1
Air

Conditioning
Unit
and
Air
Flow

AC
2

REFRIGERATION

SYSTEM

If

you
were
to

paint
your
rmger

with
alcohol

your
finger
would
feel

cold
This
is

because
the

liquid
alcohol

takes
heat

away
from

your

rmger

while
it

evaporates
If

a

quickly
evapo

rating
liquid
such

as
alcohol
is

placed

in
a
container
inside
a
box
the
tern
Air

Conditioning

perature
inside
the
box

will

drop
This

is

because
the

alcohol
is

evaporated

absorbing
the
heat

from
the
air

inside

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

1
r
I

Outside
air

U

Condenser

r
lf
P

9

n

U

Receiver
drier

AC378A

The

operation
of
the
five
devices
of

the

refrigeration

system
are
described

below

EVAPORATOR

The
heat
of
the
inside
air
which
is

force
irculated

by
the
blower
motor

is

absorbed
by

vaporizing
the

liquid

refrigerant
passed
through
the

evapora

tor
This
cools
the
air
l

t
High
pressure

gas

I
High
pressure

liquid

Compressor

Jj

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
refriger

ant

gas
is

compressed
to
a

high

pres

sure
and

high

temperature

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

Fig
AC
2

Low

pressure

liquid

C
J
Low
pressure

gas

Inside
air

v

n

Blower

1f
motor

Cooled
air

Fig
AC
2

Refrigeration
Cycle

CONDENSER

The
condenser
is

installed
to
the

front
of
the
radiator
The
heated
and

compressed
refrigerant

gas
from
the

compressor
condenses
to
a

liquid
by

being
cooled

by
air

passing
between

the
fins
of
the
condenser

VACUUM
SYSTEM

MAGfilET
VALVE

The

magnet
valve
is

located
be

tween
the

fast
idle
actuator
and

the

intake
manifold
vacuum

con

nector

Valve

cloaed

When
current
to
the
coil
is
inter

rupted

passage
on
the
intake
mani

fold
side

closes

leaving
the

actuator

side

line

open
to
the

atmosphere

Actuator

side

j

I

i

r
1
Filter

2
Return

spring

3
Coil

AC175A
4

Valve

Intake
manifold
side

Fig
AG
6

Magnet
Valve

Glosed

Velve

open

While
the

magnet
valve
coil
is

energized
by
an
electric
current
it

holds
the
valve
needle
in
the

raised

position
and
vacuum
is

imposed
on

the

vacuum
actuator
from
the
intake

manifold
Air

Conditioning

Actuator
side

AC176A
Intake
manifold

side

Fig
AG
7

Magnet
Valve

Open

FAST
IDLE
CONTROL

DEVICE
F
I
C
D

FAST

IDLE
ACTUATOR

The
fast

idle
control
device
in

creases

engine
idle

speed
so
that
the
air

conditioner
continues
to
cool
the

pas

senger
compartment
even
when
the

car

is
at
a

standstill

The
device
is
a
vacuum
actuator

and
is

equipped
with
a

diaphragm
The

diaphragm
deflects
when
vacuum

pres

sure
is

applied
and
as
a
result
the

operating
wire
attached
to
it
is
moved

The

operating
wire
is
connected
with

the
carburetor
throttle
lever
When

the

vacuum

pressure
acting
on
the
dia

phragm
is
lost
the

diaphragm
is

reo

turned
to
its

original
position

AC
6
1

Adjusting
screw

2
Lock
nut

3

Diaphragm

AC266A

Fig
AG

B
FlUI
Idle

Actuator

INTAKE
ACTUATOR

The
intake
actuator
is

actuated

by

the

intake
vacuum
or
the

atmospheric

air
introduced

by
turning
on
or
off
the

vacuum
switch

thereby
opening
or

closing
the
intake

door
The
intake

port
for

atmospheric
air
is

located
on

the
vacuum

switch

The

check
valve

is

a
one

way
valve

and
it

prevents

negative
pressure
from

passing
through
it

except
when
the

pressure
at
the
actuator
side
is

higher

than
at
the

intake
manifold
side

thus

eliminating
the
variation
in

opening
or

closing
the
intake
door

due
to
the

variation
in
the

engine
manifold
vacu

urn

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

Note
Exercise

care
when

handling
re

frigerant
as
it
is

stored
under

high

pressure

COMPRESSOR
OIL

The

SUNISO
5GS

refrig
ration

lubricant
should
be
used
to
assure
the

successful

compressor
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
lubrica

tion

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

MAINTENANCE

The

following
checks
and
main

tenance
are

especially
important
to
the

air
conditioner

I

Check

refrigerant
level

2
Check

refrigerant
leaks

3
Check

compressor
drive

belt
for

proper
deflection

4

Even
in

the
off
season
turn
the

compressor
for
10
minutes

at
least

once
a
month

by

running
the

engine
at

1

500

rpm

GENERAL

SERVICE

INSTRUCTIONS

If
dirt
water
or
air
enters

the
air

conditioner

system
it

will
be

seriously

affected
Be

sure
to
observe

the

following

I

Always
keep
the

working
place

clean

and

dry
and
free
from
dirt
and
Air

Conditioning

GENERAL
SERVICE

dust

Wipe
water
off
from
the
line

fittings
with
a

clean
cloth
before
dis

connecting

2

Have
all

necessary
tools

in

prepar

ation
beforehand

and
have
tools
clean

and

dry

3

Handling

plug
when

the

system

line
is

disconnected

4

Handling

compressor
oil

For
details
refer
to
each

descrip

tion
in
this

manual

SAFETY

PRECAUTIONS

WARNING

1
Since
direct
contact
of
the

liquid

refrigerant
with

your
skin

will

cause
frostbite

always
be
carelul

when

handling
the

refrigerant

Always
wear

goggles
to

protect

your

eyes
when

working
around

the

system

2
The

refrigerant
service
container

has
a
safe

strength
However
if

handled

incorrectly
it
will
ex

plode
Therelore

always
follow

the
instructions
On
the

label
In

particular
never
store
it
in
a
hot

location
above
520e

1260F

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

relrigerant

gas
is
heavier
than
air
and

will

lay
close

to
the
floor

be

espe

cially
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

contacu
fire
and

special
care
is

therefore

required
when
check

ing
for

leaks
in
the

system
with
a

halide
torch

5
Do
not
steam
clean
On
the

sys

tem

especially
condenser
since

excessively
high
pressure
will

build

up
in
the

system
resulting

in

explosion
of
the

system

The

above

precautions
are
essen

tial

in

handling
of

Refrigerant

12
and
their
strict
observation

AC
9
requires
sufficient

training

Therefore
it
is
of
first

impor

tance
that

any
other

personnel

than
a
well
trained
serviceman

should
not
be

allowed
to
handle

the

refrigerant

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

1
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

fonn

Consequently
the
effective

thermal
transmission
area
of
condenser

for

refrigerant
gas
will

be
reduced
and

refrigerant
gas
to
be

condensed
will

be

reduced
The

pressure
rise
will
become

proportional
to
the
volume

of
the
air

in

system

2
When
air
and

refrigerant
are

r
tixed
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

4

Wfefrlgerant

charging
speed
slows

down

charge
it
while

running
the

compressor
for

ease
of

charging
After

having
taken

the

steps
up
to

3
above

proceed
with

charging
in
the

following

order

1
Shut

off

high
pressure
valve
of

manifold

gauge

2
Run

the

engine
at

idling

speeds

below
1

500

rpm

3
Set
the

Temperature
lever
and

Fan

switch
at
maximum
cool
and

maximum

speed
respectively

To

Lpw
pressure

service

valve

t
Air

Conditioning

4

Charge

efiigerani
while
con

trolling
low

pressure
gauge
reading
at

2
8

kg
cm2

40

psi
or

less

by
turning

in

or
out
low

pressure
valve
of
mani

fold

gauge
See

Fig
A

20

WARNING

Never

charge
refrigerant

through

high

pressure
side

discharge
side

of

system
since
this
will

force
re

frigerant
back
into

refrigerant
can

and
can

may
explode

To

High
pressure

service
valve

A

5
When

refrigerant
can
is

empty

fully
close
both
valves

of
manifold

gauge
and

replace

refrigerant
can
with

a
new

ot
e

Before

opening
manifold

gauge

valve
to

charge

refrigerant
from
new

can
be

sure
to

purge
air

from
inside

charging
hose

6

Charge
the

specified
amount
of

refrigerant
into

system
by
weighing

charged

refrigerant
with

scale
Over

charging
wiU

cause

discharge
pressure

to
rise
AC380A

Fig
AC
20
Charging
Refrigeront

Measure
the
amount

of

charged
refrigerant

with
a

scale

Make
a
note

of
the

amount

charged
from

can

AC252

Fig
AC
21

Chorging
Refrigeront

Refrigerant
capacity

Unit

kg
lb

Refrigerarit
Minimum

Maximum

R
12

0
8
1
8

1
0
2
2

AC14
Note
The

p
Ce
of
btibble
hi

sight
glass
of
receiver
drier
is

an

unsuitable

method
of

checking
the

amount
of

refrigerant

charged
in

system
The
state
of
the
bubbles

iJt

sight
glass
should

only
be
used
ior

checking
whether
the
amount
of

charged

refrigerant
is
small
or

not

The
amount
of

charged

refrigerani

can
be

correcdy

judged
by
means

of

discharge
pressure
Refer
to
Re

frigerant
Level
Check

7
After

the

specified
amount
of

refrigerant
has
been

charged
intosys

tern
close
manifold

gauge
valves
Then

detach

charging
hoses
from
service

valves
of

system
Be

sure
to
install

valve

cap
to
service

valve

8

Confirm
that

there
are
no
leaks
in

system
by
checking
with
a
leak
detec

tor

Refer

to

Checking
for

Leaks

Note

Conducting
8

performance
test

prior
to

removing
manifold

gauge
is

8

good
service

operation
Refer
to

Performance

Test

CHECKING
FOR

LEAKS

Conduct
a
leak
t
st
whenever
leak

age
of

refrigerant
is

suspected
and

when

conducting
service

operations

which
are

accompanied
by

disassembly

or

loosening
of
connection

fittings

Refrigerant
is

a
colorless
odorless

gas
and

leakage
from

system
is

diffi

cult
to
detect

Accordingly
the
use
of

a
leak
detector
facilitates
check
for

leaks
Two

methods
of

checking
are

available
one

employs
a

halide
leak

detector
which
bums

propane

gas
or

butane

gas
and
the
other
is

an
electric

type
leak

detector

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

HALIDE
LEAK
DETECTOR

Since
the

propane
leak
detector
and

butane
leak
detector
are
the
same
in

respect
to
their

operation
this
section

describes
the

operation
of
the

propane

leak
detector

The

copper
screen
is
heated

by
the
Air

Conditioning

burning
of

propane
Refrigerant
gas

decomposes
to
color
the

flame
when
it

contacts
the
heated

screen
The

gas
to

be
checked
is
drawn
into
the

sampling

tube
and

sent
out
to
the
burner
A

refrigerant
leak
can
clearly
be

detected

by
variations
in
the
color
of
the

flame

1

Copper
reaction

plate

2
Flame

adjusting
lines

3
Burner

4

Sampling
tube

5
Strainer

6
Gas
bomb

7

Flame

adjuster

AC010

Fig
AC
22
Checking
for
Leaks
4

The
flame
will
be

almost
colorless

when
there
is
no

refrigerant
gas
being

burned
When
there
is

a
small

refriger

ant

gas
leak
the
flame
will
be

green
or

yellowgreen
When

refrigerant
gas
leak

age
is

large
the
flame

will
be
brilliant

blue
or

purple
Since
the

color
of
the

flame
will
be

yellow
when
dust
is

being
burned

or
there
is

aging
scale
on

copper
reaction

plate
always
keep
the

strainer

of

sampling
tube
and
reaction

plate
clean

5

Major
check

points

l
Compressor

Compressor
shaft
seal

rotate
the

compressor
by
hand

Flexible
hose

connections

Front
and
rear

head

gaskets

Service
valve

2
Condenser

Condenser

pipe
fitting

Condenser
inlet
and

outlet

pipe

connections

3
Refrigerant
lines

Flared
section
of

high

pressure
and

low

pressure
flexible
hoses

Une

connections

4

Evaporator
housing

Inlet
and
outlet
line
connections

Expansion
valve

Propane
type
Butane

type

ELECTRIC
LEAK
DETECTOR

NO
LEAK

Greenish
blue
Pale

blue

For
the

operational
procedures

SMALL
LEAK
Yellow

Bright
blue
refer

to
the
instructions
furnished
with

LARGE
LEAK

Purple
Vivid

green
each
electric
leak
detector

Discharge
refrigerant
in
one
or

two
seconds

to
ascertain

that

system

has

a
sufficient

pressure
needed
for

leak
detection

Charge
with
0
4

kg
0
9

Ib
of

refrigeranl
if

necessary

2

Light
leak
detector

Adjust
the

height
of
the
flame
between

flame

adjusting
lines
at
the

top
and
bottom

of
combustion
tube

A
reaction

plate

will

immediately
become
red
hot

3
Place
the
end
of

sampling
tube

near
the

point
of
the

suspected
leak
in

system

Note

a
Since

refrigerant
gas
is

heavier
than

air
small
leaks

can
be

easily
detect

ed

by

placing
sampling
tube
direct

ly
below
the
check

point
b
Suitable
ventilation
is

required
If

refrigerant
gas
is

mixed
with
the

surrounding
air
leak
detector
will

always
indicate
a

response
and

detection
of
the
actual
leak
will
be

difficult

c
Never

hold
leak
detector
at
an

angle

WARNING

a
Never
inhale
the
fumes

produced

by
combustion

of

refrigerant
gas

since

they
are
toxic

b
Never
use
halide
torch
in
a

place

where
combustible
or

explosive

gas
is

present

AC
15
REFRIGERANT

LEVEL
CHECK

SIGHT

GLASS

Sight
glass
is

provided
at
the

top
of

receiver

drier
One

guide
for
whether

there
is

enough
refrigerant
in

syst
m
is

given
by
observing
refrigerant
flow

through
sight
glass
However
this

method
is
unsuitable
for

judging
the

aJTlount
of

refrigerant
The
correct

refrigeranl
level
can
be

judged
by

measuring
the

system
pressures
in

ac

cordance
with
the

procedures
as
de

scribed
in
Performance
Test

1

Start
the

engine
and
hold

engine

speed
al
1

500

rpm

2

Set
AIR
lever
to

AlC

position

I

I

3
Set

temperature
lever
to
max

imum

cold

position
Air

Conditioning

4

Sefblower
to
maximum

speed

S

Check

sight
glass
after

the

lapse

Almost
no

refrigerant

Check
item

Temperature
of

high
prenure

and
low

pressure
lines
Almost
no
difference

between

high
presswc

and

lowpressufC
side

temperature

State
in

sight
gl
ltS3
Bubbles
flow
continu

ously
Bubbles
will

disappear
and
some

thing
like

mist
wiD

flow
when

rerrigel
l
llt

is

nearly

gone

AC256

Pressure
of

system
High
pressure
side
is

abnormally
low

Repair
Stop
compressor
and

conduct
an

overall

check

Note

a
The
bubbles
seen

tbrough
the

sight

glass
are
influenced

by
the
ambient

tempemture
Since
the
bubbles
are

bard
to
show

up
in

comparatively

low

tempemtures
below
200C
680

F
it
is

possible
that
a

slightly

larger
amouot
of

refrigemot
would

be
filled
if

supplied
according
to

tbe

sight
glass
Be

sure
to
recheck

the
amount
when
it

exceedS
20
C

680F
In

higher
tempemture
tbe

bubbles
are

easy
to
show

up
Insufficient

High
pressure
side
is

warm
and

low

pressure

side
is

fairly
cokt

The
bubbles
are
seen

at
intervals
of
1
2

seconds

AC257

Both

pressures
on

high

and
low

pressure
sides

are

slightly
low

Check
for
gas

leakage

repair
as

required
re

plenish
and

chaxge

system

b
Wben
the
screen
in
tbe
receiver

drier
is

clogged
tbe
bubbles
wiD

appear
even
if
the
amount
of

refrig

erant
is

nonnaL
In
this
case
tbe

outlet
side

pipe
of
tbe
receiver
drier

becomes

considembly
cold

AC
16
of

abOut
five
rilintJtes

Jullgeaccording

to
the

following
table

Suitable
Too
much

refrigerant

High
pressure
side
is

hot
and
low

pressure

side

is
cold
High
pressure
side
is

abnormally
hot

Almost
transparent

Bubbles

may
appear

when

engine
speed
is

raised
and
lowered
No
bubbles
can
be
seen

No
clear
difference
exists
these
two

conditions

nl

AC258

Both

pre55ures
on

high

and
low

pressure
sides

are

normal
Both

pressures
on

high

and
low

pressure
sides

are

abnonnally
high

Discharge
refrigerant

from
service
valve
of

low

pressure
side

PERFORMANCE
TEST

Check
for
the
amount
of

refrigerant

in
the

system
can
be
made

by
meas

uring
pressure
on

discharge
side

The
correct
amount
of

refrigerant
is

in

the

system
if

pressure
on
the

discharge
side
i
within
the

specified

range
For
details
refer
to
Trouble

Diagnoses
and
Corrections
for

per

fannance
test

Overcharging
will
show

up
in

higher

presstJre
on

discharge
side

COMPRESSOR

OIL
LEVEL
CHECK

The
oil
used
to
lubricate

compres

sor
circulates
into

system
from
the
oil

sump
while

compressor
is

operating

Therefore
to

correctly
measure
com

pressor
oil
the
amount
of
oil

flowing

to

system
must
be
considered
If
a

considerable
amount
of

leakage
of

refrigerant
gas
happens
the

leakage
of

compressor
oil
is
also

considered

There
will
be
no

compressor
oil
leak

age
from
a

completely
sealed

system

When

system
operates
under

satisfying

condition
the

compressor
oil
level

check
is

unnecessary

When

checking
the
level
of
com

pressor
oil

or
when

replacing
any

component
part
of
the

system
use
the

following
service

procedure
This

facio

litates
to

return
oil
to

compressor

1

Operate
compressor
at

engine

idling
speed
I
OOO

rpm
or
below

with

controls
set
for

maximum

cooling

and

high
blower

speed
for
10
to
15

minutes
in
order

to
return
com

pressor

oil
to

compressor

2

Stop
the

engine
and

discharge

refrigerant
of

system
and
then

remove

compressor
from
the

car

3

Remove

compressor
filler

plug

Drain

compressor
oil
from

compres

sor
oil

sump
and
measure
the
amount

AC742

Fig
AC
23
Filler
Plug

4

Compressor
oil
is

satisfactory
if

the

following
amount
of
oil
remains
in

the

compressor

Residual
oil

140
to
220
cc

4
7

to
7
4
US
fl
oz

4
9
to
7
7

Imp
fl
oz
Air

Conditioning

5
Check
the

cleanliness
of
the

oil
If

the
oil
contains

chips
or
other

foreign

material
clean

oil

sump
with
new
oil

6
Discard
the
used
oil
and
fill
with

the
same

amount
of

new
oil
Add

oil
if

found
less

than
above
amount

If

compressor
is

inoperative
due

to

faulty
compressor
or

heavy
loss
of

refrigerant
remove

compressor
and

repair
as

necessary
Then

pour
oil

up

to

correct
level
and
install
on

engine

After
above

steps
have
been

com

pleted
recheck

oil
level
drain
oil

to

correct
level

if
level
is

excessively
high

CAUTION

a
The
oil
should
not
be
transfused

from
a
container
into
another
as

the
failure
will

possibly
cause

moisture
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

PERFORMANCE
TEST

The

cooling

per
ormance
of
the

air

conditioner

changes
considerably
with

changes
in

surrounding
conditions

Testing
must
be

performed
using
the

correct
method
This
test
is
used
to

judge
whether

system
is

operating
cor

rectly
and

can
also
be
used

as
a

guiqe

in

checking
for

problems

1
Park
the

car
indoors
or
in
the

shade

2

Open
all
the
windows

of
the
car

fully
However
close
the
doors

3

Open
the
hood

4
Connect

manifold

gauge
to

high

and
low

side
service
valves
of
the

system
Refer
to

Handling
Manifold

Gauge

5

Set
air
lever
to

AIC

position

6
Set

temperature
lever
to
maxi

mum
cold

position

7

Set
blower
to
its

highest

speed

8
Start
the

engine
and
hold

engine

speed
at
1
500

rpm

9
After
the
air
conditioner
has
been

operated
for
about
10
minutes
meas

ure

system
pressures
at

high
pressure

discharge
side
and
low

pressure
suc

tion

side

10
Measure
the

temperature
of
dis

AC
17
charge
air
at
the

center
outlet

grille

11
Measure

the

temperature
and

humidity
of
the

evaporator
in
take
air

at

the

recirculating
air
inlet

of
the

evaporator

12
Measure
the

temperature
and

humidity
of
the
ambient
air
at
a

point

I
m
3
3
ft

front
of

condenser

However
a

dry
bulb

and
wet
bulb

must
not
be

placed
in

direct
sunlight

13

Check
for

any
abnormalities
by

comparing
the
test
results

with
stand

ard

pressure
Refer
to

Performance

Chart

Note

a

The

pressure
will

change
in
the

following
manner
with

changes
in

conditions

When

blower
speed
is
low
dis

charge
pressure
will

drop

When
the
relative

humidity
of
in

take
air
is
low

discharge
pressure

will

drop

b

The

temperature
will

change
in
the

following
manner

with

changes
in

conditions

When
the
ambient
air

temperature

is
low
the
outlet
air

temperature

will
become
low

If
the
test
reveals
that

there
is

any

abnormality
in

system
pressure
isolate

the

cause
and

repair
Refer
to
Trouble

Diagnoses
and
Corrections

REFRIGERANT

LEAKS

If
leaks
are

noticeable
leaky
parts

should
be

repaired
Then
system

should

be
fIlled
with

refrigerant

CAUTION

00

not

operate
compressor
with

refrigerant
level

excessively
low

If
this
caution
is

neglected
a
burnt

compressor
will
result
since

heavy
loss

of

refrigerant
usually
indicates

heavy

loss
of

compressor
liil

I

f

system
has
been

exposed
to

atmosphere
for

an
extended

period
of

time

I
receiver

drier
must
be

replaced

If
leaks
are

slight
and

no
air
is

present

in

system
add

refrigerant
as

necessary

To
detect
leaks

refer
to

Checking