Thermo King KD-II SR, Manual

Page: 165 / 182

151
Refrigeration Diagnosis
Rapi
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Hig
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ress
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re
Low hea
d
pr
es
s
u
re
No h
ead
pr
es
su
re
H
igh
su
ct
io
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p
re
ssu
re
Low su
cti
on pr
es
su
re
N
o
su
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pr
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su
re
Uni
t op
er
ati
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n
a
va
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um
Rec
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ight g
la
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s
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Su
cti
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fr
o
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ti
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Unab
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to p
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s
tem
U
nab
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to p
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ll v
a
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in
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ide
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low
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SY
MP
TOM
POSSIBLE CAUSES
• • • •
Overcharge of refrigerant
• • • • • • Shortage of refrigerant
• • • • • No refrigerant
• Air through condenser too hot (ambient)
•
Air flow through condenser restricted
• • • Air through condenser too cold (ambient)
• • •
Air in refrigerant system
• Condenser fan blades bent or broken
• Air short cycling around evaporator coil
• Air through evaporator restricted
• • • •
Evaporator needs defrosting
• • Compressor discharge valves leaking
• •
Compressor suction valves leaking
• Too much compressor oil in system
• Faulty oil pump in compressor
• Loose compressor pulley
•
Compressor bearing loose or burned out
• • • • • Broken valve plate in compressor
• •
Expansion valve power element lost its charge
• • Expansion valve feeler bulb improperly mounted