Technical information

UGH021/0301 VL Series Portable Chillers, 2 to 40 Tons
Page: 45
C. FILTER-DRIER: the filter-drier
removes contaminants and moisture
from the liquid refrigerant (figure
6.2C).
D. LIQUID LINE SOLENOID VALVE:
controlled by the instrument, this
valve closes when the compressor
cycles off to prevent refrigerant liquid
from migrating to the evaporator.
The valve opens when the
compressor cycles on (figure 6.2D).
E. REFRIGERANT SIGHT GLASS: the
refrigerant sight glass indicates
refrigerant charge and moisture
content. Refrigerant charge is
determined by a clear liquid flow.
Bubbles indicate low refrigerant.
Moisture content is indicated by the
color of the element. Element color is
normally green. If the color of the
element is chartreuse or yellow, the
system has been contaminated with
moisture. In such case, the filter-drier
must be replaced. The replacement
of the filter-drier must be completed
by a qualified refrigerant service
technician (figure 6.2E).
E. EXPANSION VALVE: the expansion
valve throttles flow of refrigerant
liquid into the evaporator and creates
a pressure drop in the refrigerant
system that allows the liquid
refrigerant to “boil off” inside the
evaporator (figure 6.2F).
F. EVAPORATOR: the evaporator is a
brazed plate heat exchanger where
the refrigerant liquid is allowed to
evaporate (boil off) to absorb heat
(BTU) from the process fluid. As the
heat is absorbed, the process fluid is
chilled (figure 6.2G).
G. HOT GAS BY-PASS SOLENOID: the
hot gas by-pass solenoid prevents
short cycling of the compressor by
reducing the capacity by 50% when
the process fluid temperature nears
the setpoint (figure 6.2H).
Typical filter-drier
Figure 6.2C
Typical liquid line
solenoid valve
Figure 6.2D
Typical refrigerant sight glass
Figure 6.2E
Fans
Blower
Figure 6.2B2