User manual
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c.  High suction pressure and high head pressure 
 Low superheat and high subcooling 
d.  High to normal suction pressure and high head pressure 
 Low subcooling 
e.  High suction pressure and high head pressure 
 Low subcooling 
f.  High suction pressure and high head pressure 
 High superheat 
g.  Low suction pressure and low head pressure 
 High superheat and low subcooling 
h.  Low suction pressure and low to normal head pressure 
 High superheat and high subcooling 
i.  Low suction pressure and low head pressure 
 Low subcooling 
j.  Low suction pressure and low head pressure 
 Low superheat and low subcooling 
k.  Low suction pressure and low to normal head pressure 
 High superheat and normal to high subcooling 
l.  Low suction pressure and normal head pressure 
 High superheat and normal subcooling 
m.  Low suction pressure and high head pressure 
 High superheat and high subcooling 
n.  Low suction pressure and high head pressure 
 High superheat and high subcooling 
o.  low to normal suction pressure and high head pressure 
 High to normal superheat and high subcooling 
c. Overcharge 
d. Non-condensable gas 
e.  Air restricted, dirty condenser, 
bad condenser fans 
f.  High room temperature, high 
evaporator load 
g. Undercharge 
h. Liquid line restricted after 
receiver, solenoid valve 
restricted 
i.  Suction line restricted 
j.  Air restricted at evaporator, 
evaporator iced 
k. Evaporator restricted 
l.  Expansion valve restricted 
m.  Both evaporator and condenser 
restricted 
n. Liquid line restricted before 
receiver 
o. Condenser restricted 
5. Valve Operation 
 SPINDLE BACK POSITION SPINDLE FRONT POSITION SPINDLE MIDDLE POSITION 
Fig. 2.1 Valve Operation 
Back Position: Process and manometer port closed for normal operation 
Front Position: Main connection to liquid or suction line closed 
Middle Position: All ports open for vacuum, charge and measurement 





