8
coolinG onlY room air conditionerS: troUBleSHootinG tiPS
n
o
it
c
A
e
s
u
a
C
e
l
b
i
s
s
o
P
m
e
l
b
o
r
P
Unit does not run
Fuse blown or circuit tripped
Replace fuse, reset breaker. If repeats, check
fuse or breaker size. Check for shorts in unit
wiring & components
Power cord not plugged in
Plug it in
System switch in “OFF” position
Set switch correctly
Inoperative system switch or open
control board
Test for continuity
Loose or disconnected wiring at
switch, control board or other com-
ponents
Check wiring & connections. Reconnect per
wiring diagram
n
o
it
c
A
e
s
u
a
C
e
l
b
i
s
s
o
P
m
e
l
b
o
r
P
Evaporator coil
freezes up
Dirty
fi
l
a
u
n
a
M
s
’r
e
n
w
O
n
i
d
e
d
n
e
m
m
o
c
e
r
s
a
n
a
e
l
C
r
e
tl
Restricted air
fl
ow
Check for dirty or obstructed coil. Use
pressure wash or biodegradable cleaning
agent to clean
Inoperative t-stat or thermistors
Test for continuity
Short of refrigerant
De-ice coil & check for leak
Inoperative fan motor
Test fan motor & replace if inoperative
Partially restricted capillary tube
De-ice coil. Check temp. differential (delta T)
across coil. Touch test coil return bends for
same temp. Test for low running current
n
o
it
c
A
e
s
u
a
C
e
l
b
i
s
s
o
P
m
e
l
b
o
r
P
Compressor runs
continually & does
not cycle off
Excessive heat load
Unit undersized. Test cooling performance &
replace with larger unit if needed
Restriction in line
Check for partially iced coil & check
temperature split across coil
Refrigerant leak
Check for oil at silver soldered connections.
Check for partially iced coil. Check split across
coil. Check for low running amperage
Thermistor shorted
Replace thermistor or electronic control board
n
o
it
c
A
e
s
u
a
C
e
l
b
i
s
s
o
P
m
e
l
b
o
r
P
Control does not
turn unit off
Control at coldest point
Turn to higher temp. setting to see if unit
cycles off
Incorrect wiring
Refer to appropriate wiring diagrams
Unit undersized for area to be
cooled
Refer to industry standard sizing chart
Defective thermistor
Replace thermistor or electronic control board
