Thermo King KD-II SR, Manual

Page: 166 / 182

Refrigeration Diagnosis (Rev. 04/03)
152
• • •
Expansion valve feeler bulb making poor contact
• • Expansion valve open too much
• • 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
• Evaporator shutter open
• • •
Evaporator shutter stuck closed
• Discharge service valve back seated
•
Suction service valve back seated
• • • • • • • Faulty three-way valve
• • • • • Faulty pilot solenoid
• • Loose or broken electrical connections
• • • • •
Thermostat or thermometer out of calibration
• • • • Suction pressure gauge out of calibration
•
Leaky receiver tank outlet valve
• Leaky bypass check valve
• • • • • Leaky condenser check valve
Rapi
d c
y
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lin
g
be
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Uni
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n
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and
def
ro
st
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U
n
it
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at
s
in
re
fr
ige
ra
tio
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y
c
le
Hig
h
he
ad p
ress
u
re
Low hea
d
pr
es
s
u
re
No h
ead
pr
es
su
re
H
igh
su
ct
io
n
p
re
ssu
re
Low su
cti
on pr
es
su
re
N
o
su
ct
io
n
pr
es
su
re
Uni
t op
er
ati
ng i
n
a
va
cu
um
Rec
e
iv
e
r s
ight g
la
s
s
em
pty
Su
cti
on li
ne
fr
o
s
ti
ng bac
k
Unab
le
to p
u
mp
dow
n s
y
s
tem
U
nab
le
to p
u
ll v
a
c
uum
in
lo
w
s
ide
U
nab
le
to h
o
ld
v
a
c
uum
in
low
si
de
N
o
is
y co
m
p
re
s
s
o
r
Uni
t no
t r
e
fr
ig
er
ati
n
g
Uni
t no
t hea
tin
g
o
r d
e
fr
os
ti
ng
SY
MP
TOM
POSSIBLE CAUSES