12
TROUBLESHOOTING INFORMATION
Complaint
Unsatisfactory
Cooling
POSSIBLE CAUSE
DOTS IN ANALYSIS
GUIDE INDICATE
"POSSIBLE CAUSE"
SYM
PT
O
M
S
ys
tem
w
ill
not
s
tar
t
C
om
pr
es
sor
w
ill
not
s
tar
t -
fan r
uns
C
om
pr
es
sor
and C
ondens
er
F
an w
ill
not
s
tar
t
E
vapor
at
or
fan
w
ill
not
s
tar
t
C
ondens
er
fan w
ill
not
s
tar
t
C
om
pr
es
sor
runs
- goes
of
f on ov
er
load
C
om
pr
es
sor
c
yc
les
on ov
er
load
S
ys
tem
runs
c
ont
inuous
ly
- l
itt
le c
ool
ing
Too c
ool
and t
hen t
oo w
ar
m
N
ot
c
ool
enough on w
ar
m
day
s
C
er
tai
n ar
eas
to c
ool
ot
her
s t
o w
ar
m
C
om
pr
es
sor
is
noi
sy
Low
s
uc
tion pr
es
sur
e
Low
head pr
es
sur
e
H
igh s
uc
tion pr
es
sur
e
H
igh head pr
es
sur
e
Test Method
Remedy
Power Failure
•
Test Voltage
Blown Fuse
•
•
•
Impact Fuse Size & Type
Loose Connection
•
•
•
•
Inspect Connection - Tighten
Shorted or Broken Wires
•
•
•
•
•
•
Test Circuits with Ohmmeter
Open Overload
•
•
Test Continuity of Overloads
Faulty Thermostat
•
•
•
•
Test Continuity of Thermostat and 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 and Contacts
Faulty Fan Relay
•
Test Continuity of Coil and Contacts
Open Control Circuit
Test Control Circuit with Voltmeter
Low Voltage
•
•
•
Test Voltage
Faulty Evaporator Fan Motor
•
•
Repair or Replace
Shorted or Grounded Fan Motor
•
•
•
Test Motor Windings
Improper Cooling Anticipator
•
Check Resistance of Anticipator
Shortage or Refrigerant
•
•
•
•
Test For Leaks, Add Refrigerant
Restricted Liquid Line
•
•
•
•
Replace Restricted Part
Undersized Liquid Line
•
•
•
Replace Line
Undersized Suction Line
•
Replace Line
Not Enough Air across Indoor Coil
•
•
•
•
Speed Blower, Check Duct Static Pressure
Too Much Air across Indoor Coil
•
Reduce Blower Speed
Overcharge of Refrigerant
•
•
·
•
•
Recover Part of Charge
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
High Pressure Control Open
•
Reset and Test Control
Unbalanced Power, 3PH
•
•
•
Test Voltage
Wrong Type Expansion Valve
•
•
•
Replace Valve
Expansion Valve Restricted
•
•
•
•
•
•
Replace Valve
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
No Cooling
System
Operating
Pressures
For detailed service information, refer to the
Remote Condensing Unit Service manual.
NOTICE
Units with rotary or reciprocating compressors and non-
bleed TXV’s require a Hard Start Kit.
