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Table 43—Cooling Service Analysis
PROBLEM CAUSE REMEDY
Compressor and Condenser Fan
W
i
l
l
N
S
Power failure. Call power company .
C
o
m
p
r
e
s
s
o
r
a
n
d
C
o
n
d
e
n
s
e
r
F
a
n
Will Not Start.
Fuse blown or circuit breaker tripped. Replace fuse orreset circuit breaker.
Defectivethermostat,contactor,transformer,or
control relay.
Replace component.
Insufficient line voltage. Determine causeand correct.
Incorrect or faulty wiring. Check wiring diagram and rewire correctly.
Thermostat settingtoo high. Lower thermostat settingbelowroom tempera-
ture.
Compressor Will Not Start
But Condenser Fan Runs.
Faulty wiringorloose connectionsin compres-
sorcircuit.
Check wiringand repairor replace.
B
u
t
C
o
n
d
e
n
s
e
r
F
a
n
R
u
n
s
.
Compressor motor burnedout, seized, orin-
ternal overload open.
Determine cause. Replace compressor.
Defective run/startcapacitor,overload,start
relay.
Determine causeand replace.
One leg of3-phase power dead. Replace fuse orreset circuit breaker. Determine
cause.
CompressorCycles(OtherThan
Normally Satisfying Thermostat).
Refrigerant overcharge or undercharge. R ecover refrigerant, evacuate system, andre-
charge to nameplate.
N
o
r
m
a
l
l
y
S
a
t
i
s
f
y
i
n
g
T
h
e
r
m
o
s
t
a
t
)
.
Defective compressor. Replace and determine cause.
Insufficient line voltage. Determine causeand correct.
Blocked condenser. Determine causean d correct.
Defective run/startcapacitor,overload,or start
relay.
Determine causeand replace.
Defectivethermostat. Replace thermostat.
Faulty condenser-fan motor or capacitor. Replace.
Restriction in refrigerant system. Locate restriction and remove.
Compressor Operates Continuously.
Dirty air filter. Replacefilter.
C
o
m
p
r
e
s
s
o
r
O
p
e
r
a
t
e
s
C
o
n
t
i
n
u
o
u
s
l
y
.
Unit undersizedforload. Decrease load orincrease unit size.
Thermostat set too low. Reset thermostat.
Low refrigerant charge. Locate leak, repair,and recharge.
Leaking valvesin compressor. Replace compressor.
Air in system. Recover refrigerant, evacuate system, andre-
charge.
Condenser coil dirty orrestricted. Clean coil or remove restriction.
Excessive Head Pressure.
Dirty air filter. Replacefilter.
E
x
c
e
s
s
i
v
e
H
e
a
d
P
r
e
s
s
u
r
e
.
Dirty condensercoil. Clean coil.
Refrigerant overcharged. Recover excessrefrigerant.
Air in system. Recover refrigerant, evacuate system, andre-
charge.
Condenser airrestricted or air short-cycling. Determine causeand correct.
Head Pressure Too Low.
Low refrigerant charge. Check forleaks, repair,and recharge.
H
e
a
d
P
r
e
s
s
u
r
e
T
o
o
L
o
w
.
Compressor valves leaking. Replace compressor.
Restrictioninliquidtube. Remove restriction.
Excessive Suction Pressure.
High heat load. Check forsource and eliminate.
E
x
c
e
s
s
i
v
e
S
u
c
t
i
o
n
P
r
e
s
s
u
r
e
.
Compressor valves leaking. Replace compressor.
Refrigerant overcharged. Recover excessrefrigerant.
Suction Pressure Too Low.
Dirty air filter. Replacefilter.
S
u
c
t
i
o
n
P
r
e
s
s
u
r
e
T
o
o
L
o
w
.
Low refrigerant charge. Check forleaks, repair,and recharge.
Metering device or low side restricted. Remove source of restriction.
Insufficient evaporator airflow. Increaseair quantity. Check filterandreplace if
necessary.
Temperature too low in conditioned area. Reset thermostat.
Outdoor ambient below 25 F. Install low-ambient kit.
Evaporator Fan Will Not Shut Off.
Time off delay not finished. Wait for 30-secondoff delay.
581B,C