17
TROUBLESHOOTING INFORMATION: CONDENSING UNIT
For detailed service information refer to the Remote Condensing Unit Service manual.
Complaint
System
Operating
Pressures
POSSIBLE CAUSE
DOTS IN ANALYSIS
GUIDE INDICATE
"POSSIBLE CAUSE"
SY
MP
TO
M
S
ys
tem
wi
ll not
s
ta
rt
C
om
pre
ss
or w
ill n
o
t s
ta
rt
- fa
n ru
n
s
Co
mp
.
an
d
Co
nd
. Fa
n wi
ll no
t st
ar
t
Eva
p
or
at
or
f
an wi
ll no
t
st
ar
t
C
ond
en
se
r f
a
n wi
ll not
s
ta
rt
C
om
pr
e
ss
or
r
un
s
- go
es
of
f on
o
ver
lo
ad
Co
m
pr
e
sso
r cycl
es
o
n
ove
rlo
ad
S
ys
tem
r
un
s c
on
tin
u
ous
ly
-
li
tt
le c
oo
lin
g/
ht
g
T
oo
c
o
ol
an
d
th
en
t
oo
w
ar
m
N
ot
c
o
ol
en
oug
h on
w
ar
m
da
ys
C
er
tai
n
a
rea
s t
oo
c
o
ol
,
ot
her
s
too
wa
rm
C
om
pre
ss
or is
n
o
is
y
S
ys
tem
r
un
s -
bl
o
w
s c
ol
d ai
r i
n
h
eat
in
g
Un
it w
ill
n
ot
t
e
rm
in
at
e
de
fr
os
t
U
ni
t wi
ll not
def
ro
st
Lo
w
su
cti
o
n p
re
ssur
e
L
ow he
ad
p
res
su
re
H
igh
s
u
ct
ion
pr
e
ss
ur
e
H
igh
h
ea
d
pr
es
su
re
Test Method
Remedy
Power Failure
•
Test Voltage
Blown Fuse
•
• •
Inspect Fuse Size & Type
Unbalanced Power, 3PH
•
• •
Test Voltage
Loose Connection
•
•
•
Inspect Connection - Tighten
Shorted or Broken Wires
• • • • • •
Test Circuits With Ohmmeter
Open Fan Overload
• •
Test Continuity of Overload
Faulty Thermostat
•
• •
•
Test Continuity of Thermostat & Wiring
Faulty Transformer
•
•
Check Control Circuit with Voltmeter
Shorted or Open Capacitor
•
• • • •
Test Capacitor
Internal Compressor Overload Open
•
♦
Test Continuity of Overload
Shorted or Grounded Compressor
•
•
Test Motor Windings
Compressor Stuck
•
• •
♦
Use Test Cord
Faulty Compressor Contactor
•
• •
Test Continuity of Coil & Contacts
Faulty Fan Relay
•
Test Continuity of Coil And Contacts
Open Control Circuit
•
Test Control Circuit with Voltmeter
Low Voltage
•
• •
Test Voltage
Faulty Evap. Fan Motor
•
•
♦
Repair or Replace
Shorted or Grounded Fan Motor
•
•
Test Motor Windings
Improper Cooling Anticipator
•
•
Check Resistance of Anticipator
Shortage of Refrigerant
• •
♦
• •
Test For Leaks, Add Refrigerant
Restricted Liquid Line
• •
• •
•
Remove Restriction, Replace Restricted Part
Open Element or Limit on Elec. Heater
♦
♦
Test Heater Element and Controls
Dirty Air Filter
•
• •
•
♦
Inspect Filter-Clean or Replace
Dirty Indoor Coil
•
• •
•
♦
Inspect Coil - Clean
Not enough air across Indoor Coil
•
• •
•
♦
Check Blower Speed, Duct Static Press, Filter
Too much air across Indoor Coil
♦
•
Reduce Blower Speed
Overcharge of Refrigerant
• •
•
♦
• •
Recover Part of Charge
Dirty Outdoor Coil
• •
•
♦
•
Inspect Coil - Clean
Noncondensibles
•
•
♦
•
Recover Charge, Evacuate, Recharge
Recirculation of Condensing Air
•
•
•
Remove Obstruction to Air Flow
Infiltration of Outdoor Air
•
• •
Check Windows, Doors, Vent Fans, Etc.
Improperly Located Thermostat
•
•
Relocate Thermostat
Air Flow Unbalanced
•
•
Readjust Air Volume Dampers
System Undersized
•
•
Refigure Cooling Load
Broken Internal Parts
•
♦
Replace Compressor
Broken Valves
•
•
• •
Test Compressor Efficiency
Inefficient Compressor
•
♦
• •
Test Compressor Efficiency
Wrong Type Expansion Valve
• • •
•
• •
♦
Replace Valve
Expansion Device Restricted
• • •
•
• •
•
Remove Restriction or Replace Expansion Device
Oversized Expansion Valve
•
•
Replace Valve
Undersized Expansion Valve
• • •
•
•
Replace Valve
Expansion Valve Bulb Loose
•
•
Tighten Bulb Bracket
Inoperative Expansion Valve
•
•
•
Check Valve Operation
Loose Hold-down Bolts
•
Tighten Bolts
Faulty Reversing Valve
•
♦ ♦ ♦
♦ ♦ ♦
Replace Valve or Solenoid
Faulty Defrost Control
•
♦ ♦ ♦ ♦ ♦
♦
Test Control
Faulty Defrost Thermostat
♦ ♦ ♦ ♦ ♦ ♦ ♦
Test Defrost Thermostat
Flowrator Not Seating Properly
•
• •
Check Flowrator & Seat or Replace Flowrator
•
Cooling or Heating Cycle (Heat Pump)
♦
No Cooling
Unsatisfactory Cooling/Heating
Heating Cycle Only (Heat Pump)