Service manual
5-1
T-294-01
SECTION 5
TROUBLESHOOTING
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.1 UNIT WILL NOT START OR STARTS THEN STOPS
External power source OFF Turn on
N
o
p
o
w
e
r
t
o
u
n
i
t
Start-Stop switch (ST) OFF or defective Check
N
o power to un
i
t
Circuit breaker (CB) tripped or OFF Check
Modular transformer (TRANS) not connected 6.21
Circuit breaker (CB) OFF or defective Check
L
o
s
s
o
f
c
o
n
t
r
o
l
p
o
w
e
r
Control transformer (TR) defective Replace
L
oss o
f
contro
l
power
Fuse (F3) blown Check
Start-Stop switch (ST) OFF or defective Check
Evaporator fan motor internal protector (IP) open 6.16
L
o
s
s
o
f
c
o
n
t
r
o
l
p
o
w
e
r
i
n
Condenser fan motor internal protector (IP) open 6.19
L
o
s
s
o
f
c
o
n
t
r
o
l
p
o
w
e
r
i
n
respective branch of control
Compressor internal protector (IP) open 6.8
p
circuit only
High pressure switch (HPS) open 5.7
Heat termination thermostat (HTT) open Replace
Low line voltage Check
Com
p
ressor hums
,
but does not
Single phasing Check
C
o
m
p
r
e
s
s
o
r
h
u
m
s
,
b
u
t
d
o
e
s
n
o
t
start
Shorted or grounded motor windings 6.8
Compressor seized 6.8
5.2 UNIT RUNS BUT HAS INSUFFICIENT COOLING
Compressor Compressor valves defective 6.8
Abnormal pressures 5.7
Temperature controller malfunction 5.9
R
e
f
r
i
g
e
r
a
t
i
o
n
S
y
s
t
e
m
Evaporator fan or motor (EM) defective 6.16
R
e
f
r
i
gerat
i
on
S
ystem
Stepper motor suction modulation valve (SMV) malfunction 6.24
Condenser Pressure Transducer (CPT) defective Check
Shortage of refrigerant 6.7
5.3 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING
C
o
n
t
a
i
n
e
r
Hot load Normal
C
onta
i
ner
Defective box insulation or air leak Repair
Shortage of refrigerant 6.5/6.7
Evaporator coil covered with ice 5.6
Evaporator coil plugged with debris 6.14
Evaporator fan(s) rotating backwards 6.16/6.17
Defective evaporator fan motor/capacitor 6.16/6.17
Refrigeration System
Air bypass around evaporator coil Check
R
e
f
r
i
g
e
r
a
t
i
o
n
S
y
s
t
e
m
Controller set too low Reset
Dirty condenser 6.18
Compressor worn 6.8
Current limit (Code 32) set to wrong value 3.1.4
Stepper motor suction modulation valve (SMV) malfunction 6.24