Jetson
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• 90°F to 120°F Condenser LWT: 275 to 430
psig
• 120°F to 140°F Condenser LWT: 430 to 560
psig
• Suction pressure: Take at Schrader fitting
provided on the suction line. Normal suction
pressures are:
• 42°F to 60°F LWT: 104 to 155 psig
• 15°F to 39°F LWT: 60 to 103 psig
• Check compressor oil level. At full load, oil
level should be visible in the oil level sight
glass on the compressor. If it is not, add or
remove oil as required.
• Check the liquid line sight glass. Refrigerant
flow past the sight glass should be clear.
Bubbles in the liquid line indicate either low
refrigerant charge or excessive pressure drop in
the liquid line. Such a restriction can often be
identified by a noticeable temperature
differential on either side of the restricted area.
Frost often forms on the outside of the liquid
line at this point also.
Important: The system may not be properly
charged although the sight glass is clear. Also
consider superheat, sub-cooling and operating
pressure.
• Once oil level, amp draw and operating
pressures have stabilized, measure system
suction superheat.
• Measure system liquid line sub-cooling.
• If operating pressure, sight glass, superheat and
sub- cooling readings indicate refrigerant
shortage, charge refrigerant into each circuit.
Refrigerant shortage is indicated if operating
pressures are low and sub- cooling is also low.
Important: If suction and discharge pressures
are low but subcooling is normal, no refrigerant
shortage exists. Adding refrigerant, will result in
overcharging.
• Add refrigerant with the unit running by
metering liquid refrigerant through the
Schrader valve between the expansion valve
and the evaporator refrigerant inlet until
operating conditions are normal.
System Superheat
Normal superheat is 10°F to 16°F at full load.
Expansion valve superheat is factory set. Contact
factory before making any adjustment.
System Subcooling
Normal subcooling is 5°F to 10°F at full load
where saturated discharge pressure and liquid line
temperature are measured at chiller liquid line.
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General