Piper Cherokee Six - Page 678

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
NOTE
A table
at
the end
of these
instructions
will
assist
in locating
and
correcting
malfunctions
which
may arise
in this
system.
NOTE
The air
conditioning
system
should
be operated
at least once
a
month
to
prevent
sticking
valves
and keep
the
system
lubricated.
13-4.
MALFUNCTION
DETECTION.
The
detection
of
system
malfunction
largely
depends
on
the
mechanic's
ability
to interpret
the
gauge
pressure
readings
into system
problems.
A system
operating
normally
will
have
a
low side
gauge
pressure
reading
that
will
correspond
with
the temperature
of the
refrigerant
evaporating
in the
evaporator,
allowing
for
a few
degrees
temperature
rise
due to
loss
in the
tube
walls
and
fins.
The high
side
will
have
a
gauge
pressure
that
will
correspond
with
the
temperature
of the
refrigerant
condensing
in the
condenser,
allowing
for a
few degrees
temperature
drop
due
to loss
in
the
tube
walls
and fins.
Any
deviation
from
that
which
is normal
indicates
a malfunction
within
the
system
due
to
a faulty
control
device,
obstruction,
defective
part,
or improper
installation.
Detection
of system
malfunction
is made
easier
with
the
knowledge
that
the
temperature
and
pressure
of
Refrigerant
12 is in
close
proximity
between
the
pressures
of
twenty
and
eighty
pounds
per square
inch
(psi).
A glance
at
the
temperature-pressure
chart
will show
that
there
is only
a slight
variation
between
the
temperature
and
pressure
of
the
refrigerant
in the
lower
range.
It
is correct
to assume
that
for
every
pound
of
pressure
added
to the
low
side. a
temperature
increase
of
about
one
degree
Fahrenheit
takes
place.
For
instance,
a pressure
of
23.8
on
the chart
indicates
a temperature
of
24°F.
A change
of pressure
of
almost
one
pound
to
24.6
psi gives
us
a temperature
increase
to
25
F.
NOTE
For
each
1.000
feet
of elevation
above
sea level,
the
gauge
readings
will be
about
one
inch of
mercury
or
1/2 psi
higher
than
the chart
indicates.
It
must
be pointed
out
that
the
actual
temperature
of the
air
passing
over
the coils
of
the
evaporator
will be
several
degrees
warmer
allowing
for
a temperature
rise
caused
by
the
loss
in the
fins and
tubing
of
the evaporator.
The
importance
of a seasonal
check
up of
the air
conditioning
system
should
be
brought
to
the attention
of
the customer
whenever
possible.
A
thorough
check
of
the
system
performed
in a
methodical
manner
will
reveal
trouble
the
customer
is
often
not aware
of.
ACCESSORIES
AND UTILITIES
Issued:
8/17/72
3G12