Thermo King SB-III 30 SR+, Manual

Page: 104 / 120

Refrigeration Diagnosis (Rev. 04/02)
94
• •
Expansion valve closed too much
• •
Expansion valve needle eroded or leaking
• • •
Expansion valve partially closed by ice, dirt or wax
• • •
Liquid refrigerant entering compressor
• •
Restricted line on the low side
• • • •
Restricted line on the high side
• • • •
Restricted drier
•
Defrost damper stays open
• • •
Defrost damper stuck closed
•
Discharge service valve back seated
•
Suction service valve back seated
• • • • • • • •
Faulty three-way valve
• • • • •
Faulty pilot solenoid
• •
Loose or broken electrical connections
• • • • •
Sensor out of calibration
• • • •
Compound pressure gauge out of calibration
•
Leaky receiver tank outlet valve
•
Leaky bypass check valve
•
Leaky condenser check valve
• Faulty three-way condenser pressure bypass check
valve
• • • • •
Modulation valve stuck closed
• • • • •
Hot gas bypass valve stuck open or leaking
Ra
pi
d c
y
c
lin
g bet
w
e
e
n
co
ol
an
d he
at
Un
it
c
o
o
ls i
n
he
at
and
d
e
fr
o
s
t c
y
c
le
Un
it
he
at
s
i
n
ref
ri
ger
at
io
n
c
y
c
le
Hi
g
h
he
ad pr
es
s
u
re
Low
he
ad pr
es
s
u
re
N
o
he
ad
p
re
s
s
u
re
Hi
g
h
su
c
ti
o
n pr
es
su
re
Low
su
c
ti
o
n pr
es
su
re
N
o
su
cti
o
n pr
es
su
re
Un
it
op
er
at
in
g
i
n
a
va
cu
um
Re
ce
iv
e
r s
igh
t gl
a
s
s
emp
ty
S
u
ct
io
n
l
in
e
fr
ost
ing
b
a
c
k
U
n
a
b
le
to
pu
m
p
do
w
n
sy
ste
m
Un
abl
e
to
p
u
ll
v
a
c
uum
i
n
l
o
w
s
ide
U
n
a
b
le
t
o
h
o
ld
va
cu
u
m
in
lo
w s
id
e
N
o
is
y c
o
m
p
re
sso
r
Un
it
no
t
re
fr
ig
er
at
in
g
Un
it
no
t
h
eat
in
g or
d
e
fr
o
s
ti
ng
SYM
PTO
M
POSSIBLE CAUSES