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170.600-IOM (JUN 11)
Page 12
The boiling point of a liquid is defined as the temperature at
which the vapor pressure is equal to atmospheric pressure.
The boiling point of water is 212°F (100°C). If the pressure is
lowered, so is the water's boiling point. The table indicates
the boiling point of water at very low pressures:
BOILING POINT
of WATER °F (°C)
41 (5)
50 (10)
59 (15)
68 (20)
For pumpdown, use a vacuum pump that empties the pack-
age of both air and water vapor.
The vacuum pump must be able to lower the pressure to
approximately 0.05 in. H
O (0.1-mm Hg), and it must be
2
equipped with a gas ballast valve. Use this valve as much
as possible in order to prevent the condensation of water
vapor in the vacuum pump.
IMPORTANT: NEVER use the refrigeration compressor to
pump down a system.
For pumpdown to be satisfactory, the final pressure must be
lower than 2.7 in. H
O (5 mm Hg).
2
NOTE: There is a risk that any water still present in the
refrigeration system may freeze if the ambient tempera-
tures drops below 50°F (10°C). If this occurs, add heat
to the environment of the components because ice does
not evaporate easily.
OPERATING LOG
Monitor the condition of the package. Log data manu-
ally using the History and Trending capabilities of the Frick
Quantum
™
LX. See the Quantum
shipped with the package.
This operating log should be maintained at regular intervals,
providing important information about the cause of any
undesired changes in the operating state.
The operating log should also contain data about the com-
pressor's cooling system functions, and whether there are
unusual noises or vibrations.
HIGH PRESSURE REGULATING SYSTEM
The PowerPac
unit is equipped with either a mechanical high
™
pressure float valve or an electrical sensor and motorized
expansion valve. Both systems are mounted at the outlet of
the condenser and regulate the liquid level in the condenser.
At the same time, they control the expansion between the
low pressure and high pressure sides of the chiller unit.
Mechanical Float Valve
The mechanical float valve (Figure 8) is mounted on the
condenser liquid outlet, resulting in a compact design and a
very low liquid charge.
FRICK
POWERPAC
®
OPERATION
AT PRESSURE
IN. H
O (mm HG)
2
3.6 (6.63)
4.9 (9.14)
6.8 (12.73)
9.5 (17.80)
®
™
LX Operating Manual
™
Figure 8
The float valve has a bypass boring (Position 1). This ensures
that a pressure equalization occurs at standstill between the
high and low pressure sides, with a subsequent emptying
of liquid from the float housing. The hole is placed below
liquid level, but note that a small amount of liquid may be
left when dismantling the float vessel .
The vent valve (Figure 9) is located in the middle of the end
cover of the float housing and allows access to the top of
the float housing through a tube.
Electrical Regulation
To regulate the liquid level in the condenser, a level sensor
registers the liquid level. The level is converted to a signal
which is sent to the Quantum
panel controls the opening degree of the motorized expan-
sion valve.
Level Sensor
Vent Valve
Actuator
Figure 9
LX panel. The Quantum
LX
™
™
Expansion Valve
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