To
test the air
conditioning, the
outside
temperature
should be above
60° for 24 hours
(some
manufacturers
recommend 65°).
If you turn the
air conditioning
system on when
the temperature
is below 60°,
you may damage
the compressor.
Turn
the fan switch to
“auto” and
set the
thermostat below
the room
temperature (76°
to 78° is
recommended). The
fan and
condensing unit
should come on,
unless there is a
time delay, which
may slow its
start.
Let
the system run
for eight (8) to
ten (10) minutes
to balance the
temperature in
the ductwork.
Check the
temperature at
the supply and
return registers.
The temperature
at the supply
register should
be 14° to 20°
Fahrenheit cooler
than at the
return ducts or
ambient room
temperature.
If
the temperature
differential is
more than 20°,
it indicates
restricted air.
This points to:
(1) a dirty
filter, (2)
improper
ductwork, or (3)
a fan that is
sized wrong, not
working properly,
or moving too
slowly.
If
it is less than
14°
differential, the
possible causes
are: (1)
refrigerant loss,
(2) a dirty coil,
(3) a laboring
compressor, (4)
an oversized fan,
or (5) a
deficient return
air system.
There
are two copper
lines going from
the condensing
unit on the
exterior to the
air handler on
the interior. The
smaller line is
the liquid or
high-pressure
line and will be
warm, not hot, to
the touch when it
is operating
properly. The
larger line
covered with
insulation is the
suction or low
pressure line and
will be cold to
the touch. The
suction line
should be “sweating”
or condensing,
the way a glass
of iced tea “sweats.”
It should not be
forming ice.
1.
The
refrigerant in
the system may be
low from a
possible leak.
2.
Compressor
failure is a
problem, which
usually requires
replacement of
the unit. Usually
when a compressor
is replaced, the
entire condensing
unit on the
exterior is
replaced. The
typical life
expectancy of a
compressor in a
central air
conditioning
system is 8 to 15
years, depending
on the geographic
location.
