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Wiring
and
Controls
Loose
wiring
connections, or
control
contactor defective.
Unit
Short
Cycles
(Continued)
Compressor Overload
Defective compressor overload, check
and
replace
ifnecessary
If
the
compressor runs too hot,
it
may be due
to
a
insufficient
refrigerant
charge.
Water
Lack of sufficient
pressure,
temperature, and/or quantity
of
water,
Unit
Undersized
Recalculate
heat gains
or
losses
for
space
to
be
conditioned.
If
excessive,
rectify by
adding
insulation,
shading,
etc.
Check
for
leaks
in ductwork or introduction of
ambient air through
doors
and
windows.
Improperly
located thermostat
(e.g. near
kitchen), inaccurately
sensing the
comfort
level
in
the
living
area.
Check
anticipator
setting.
Loss
of
Conditioned
Air
by Leaks
Thermostat
Airflow
Lack of
adequate
airflow or
improper
distribution of
air.
Check
the
motor
speed
or duct
sizing.
Check
the
filter,
it
should be
inspected
every month
and changed
if dirty.
Remove or
add resistance
accordingly.
Refrigerant
Charge
Low
on
refrigerant
charge
causing
inefficient operation. Adjust only
after checking
CFM
and
GPM.
Compressor
Checkfor
defective compressor.
Ifdischarge
pressure
is too
low
and
suction
pressure is
too
high,
compressor
is
not
pumping
properly.
Replace compressor.
Reversing
Valve
Defective reversing valve creating
blpass of
refrigerant
from
discharge
to
suction
side
of
compressor. When
it
is necessary
to
replace
the
reversing valve, wrap
it
with
a
wet cloth
and
direct
heat
away.
Excessive
heat can damage the
valve.
Insufficient
cooling or
heating.
Desuperheater
The
desuperheater
circuit (in-line
fuse) should
be
disconnected
during
cold
weather to
allow
full
heating load to
the house.
Dirty Filter
Check
filter.
Clean or
replace
if
found
dirty
Thermostat
Improperly
Set
Check
if
thermostat is
set
at
corect
temperature.
Defective Thermostat
Check thermostat
operation.
Replace
if
found defective.
Incorrect
Wiring
Check
for
broken, loose, or incorrect wires
Check
blower
motor
in
one
of
the
other switch
positions.
ff
it
does
not
operate, check
for
open
overload.
If
overload is open
and
motor
is
not
overheated,
replace
it.
unir
will
not
operate
on
"heating"
Blower Motor
Defective
Defective solenoid valve
will
not
energize.
Replace solenoid
coil.
Reversing
Valve
Does
Not
Shift
Unit
does
not
cool
(Heats
only)
Reversing
Valve
Does
Not
Shift,
the
Valve
is Stuck
The solenoid valve is de-energized
due
to
miswiring
at the
unit or
thermostat--correct
wiring.
Replace
if
valve is
tight
or frozen
and
will
not
move.
Switch
from
heating to
cooling
a
few
times to loosen
valve.
Compressor
Make
sure the
compressor is not
in
direct contact
with
the base
or
sides
of
the
cabinet.
Cold
surroundings
can cause
liquid
slugging.
Increase
ambient
tempgrafure.
Blower
and
Blower Motor
Blower
wheel
hitting
the
casing. Adjust for
clearance and
alignment.
Bent
blower,
check
and
replace
if
damaged. Loose
blower
wheel on
shaft,
check
and
tighten.
Defective bearings,
check
and
replace.
Noisy
Operation
Contactors
A
clattering or humming noise
in
the
contactor could
be due
to
control
voltage
less
than
18
volts.
Check
for
low
supply voltage,
low
transformer output, or extra long runs
of
thermostat wires.
If
the
contacts
are
pitted
or corroded
,
or coil
is defective,
repair
or
replace.
l4
PROBLTM
POSSIBLE
CAU,S3
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