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SAFETY CONTROL SETTINGS
The pumpout unit high-pressure switch (Fig. 3) is set to open at
the settings listed in Table 5. The switch setting is checked by op-
erating the pumpout condenser and slowly throttling the pumpout
condenser water.
When the selector switch is in the Automatic position, the pum-
pout will cycle on a low pressure/vacuum switch. This switch will
shut down the pumpout compressor when suction pressure reach-
es 7 ± 1.5 psia or 15 ± 3 in. Hg vacuum (51.7 kPa absolute). When
the selector switch is in the On position, the pumpout compressor
will continue to run until refrigerant vapor flow is so low that the
compressor motor overheats. At this time the compressor motor
overload will shut off the compressor. This is NOT recommended.
Table 5 — High Pressure Switch Settings
REFRIGERANT
185 ± 10 psig
R-513A
(1276 ± 69 kPa)
COMPRESSOR
The hermetic compressor assembly comes equipped with internal
thermal protection on the motor and a self-regulating crankcase
heater.
CONDENSER
The water-cooled condenser is a brazed plate heat exchanger.
During transfer, it condenses refrigerant vapor to liquid.
OIL SEPARATOR
The pumpout unit includes an in-line oil separator to remove oil
that becomes mixed with refrigerant and returns the oil to the com-
pressor.
SUCTION AND DISCHARGE VALVES
The pumpout unit comes with a 4-way transfer valve manifold to
interconnect both liquid and vapor transfer and to pressurize the
chiller during transfer of refrigerant from chiller to storage tank or
from one chiller vessel to another.
Storage Tank
The storage tank is rated for positive pressure refrigerants under
ASME Section VIII pressure vessel codes with a minimum of
185 psig (1276 kPa) rating. The tank components include:
DRAIN VALVE
Located at its lowest point of drain with a minimum of 1 in. NPT.
DUAL RELIEF VALVES
Two relief valves and a 3-way shut-off valve.
PRESSURE GAGE
A 30 in. Hg vacuum -0-400 psig (101-0-2760 kPa) compound
pressure gage.
LEVEL GAGE
Liquid level gage (magnetically coupled dial type) with electronic
shut-off at 90% liquid capacity.
WARNING
During transfer of refrigerant into and out of the pumpout stor-
age tank, carefully monitor the storage tank level gage. Do not
fill the tank more than 90% of capacity to allow for refrigerant
expansion. Overfilling may result in damage to the tank and
personal injury. For maximum refrigerant capacity, refer to
Table 3.
HIGH-PRESSURE SWITCH
CUTOUT
CUT-IN
140 ± 10 psig
(965 ± 69 kPa)
Overview
Transferring refrigerant from one vessel to another is accom-
plished by using either gravity or pressure differential. A differ-
ence in elevation between 2 vessels results in a gravity flow of liq-
uid; a difference in pressure forces the liquid from one vessel to
the other. The latter method requires lowering the pressure in one
vessel. If there is liquid in that vessel, its temperature must be low-
ered, and the pressure in the other vessel must be simultaneously
increased.
Under most circumstances, creating the pressure differential is not
a difficult process. Some applications, such as ice storage, outdoor
installations, or installations with high temperature differentials
between the storage tank and the chiller may require additional
consideration. In some instances, it may be necessary to add auxil-
iary heat to one of the vessels or to insulate the storage tank at job
sites where high ambient temperature or sun load make it difficult
to reduce the temperature and pressure in the tank. Outdoor instal-
lations must have a roof or cover over the storage tank to ensure
that the pressure in the tank does not exceed the chiller relief pres-
sure setting.
REFRIGERANT TRANSFER
When refrigerant is being evacuated from the chiller cooler or
condenser vessels, any liquid refrigerant left in a vessel will flash
off, lowering the temperature in that vessel enough to freeze the
fluid (usually water) flowing through the cooler or condenser
tubes. This event, called tube freeze-up, can cause extensive dam-
age to the chiller; therefore, all liquid refrigerant must be removed
from a vessel before evacuation of refrigerant vapor is started. If
all the liquid cannot be removed, then the cooler water and con-
denser water pumps must be operated throughout the process of
evacuating refrigerant vapor to keep fluid moving through the
cooler and condenser tubes.
TRANSFERRING LIQUID REFRIGERANT FROM THE
CHILLER COOLER TO THE CHILLER CONDENSER OR
PUMPOUT STORAGE TANK
Chiller and pumpout unit valves are set to permit the pumpout
compressor to discharge refrigerant vapor into the cooler vessel,
lowering pressure in the condenser vessel/storage tank. The pres-
sure differential forces liquid from the cooler vessel into the con-
denser vessel/storage tank. After all the liquid is transferred, the
refrigerant vapor remaining in the cooler vessel can be drawn off
by reducing pressure in the chiller and discharging the vapor
through the pumpout unit condenser into the condenser vessel/
storage tank.
NOTE: The pumpout selector switch can be placed in On or Auto-
matic mode. In Automatic mode, the compressor will shut off au-
tomatically once the suction pressure drops to 7 psia or 15 in. Hg
vacuum (51.7 kPa absolute). In On mode, the unit will continue to
pumpout regardless of the suction (vacuum) pressure.
TRANSFERRING LIQUID REFRIGERANT FROM THE
CHILLER CONDENSER OR PUMPOUT STORAGE TANK
TO THE CHILLER COOLER
Chiller and pump-out unit valves are set to increase pressure in the
chiller condenser vessel/storage tank and to reduce pressure in the
cooler vessel. Pressure in the cooler vessel is lowered to corre-
spond to a saturated refrigerant liquid temperature 2°F (1.1°C)
above the freezing temperature of the liquid circulating through
the chiller cooler/condenser tubes (34°F [1.1°C] for water). The
valves are set so that the pressure in the cooler vessel is lower than
that of the condenser vessel/storage tank, forcing the liquid into
the cooler vessel.
NOTE: The pumpout selector switch can be placed in On or Auto-
matic mode. In Automatic mode, the compressor will shut off au-
tomatically once the suction pressure drops to 7 psia or 15 in. Hg
11
OPERATION
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