Ingersoll-Rand 900829, Maintenance Manual

Page: 87 / 142

85
Refrigeration Diagnosis Chart
Unit
Not H
eating
Rapid
cycling
Unit
cools in
defrost
cycle
High
head p
ressu
re
Low
head
pressure
No h
ead pressure
High
suctio
n pressure
Low
suct
ion p
ressure
No su
ction
pressure
Unit
operatin
g
in vacu
um
Sight
glass / emp
ty
Suctio
n line f
ro
s
ting
back
Noisy co
mpressor
Unit
not
r
e
fr
igerating
Unit
not
defr
ost
ing
SYMP
T
OM
POSSIBLE CAUSES
• • Overcharge of refrigerant
• • • • • • • Shortage of refrigerant
• • • • • • • • No refrigerant
• Air through condenser too hot (ambient)
• Air flow through condenser restricted (dirty)
• • 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
• • Broken engine driven compressor belt
• Compressor discharge valves leaking
• • • Too much compressor oil in system
• Loose engine driven 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
• • • 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
• • Defrost solenoid stuck closed
• Condenser blocking solenoid not closing
• Water valves not open
• Water pump not working.
• Truck engine not running
• • • • Liquid refrigerant entering compressor
• • • Restricted line on the low side
• • Restricted line on the high side
• • • Restricted dehydrator
• • Reverse fan rotation
• • • • Faulty pilot solenoid
• • Loose or broken electrical connections
• • • • Gauge out of calibration
• Condenser fan motor not operating
• • • • • • Evaporator fan motor not operating