OMEGA AIR RDHP 20, Installation And Operating Manual

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5.5 Expansion valves
This valve injects a portion of the hot gases (taken
from the compressor outlet) into the tube between
the evaporator and the suction side of the
compressor, thereby maintaining a constant
temperature / pressure of the evaporator at about +2
° C. This injection prevents the formation of ice in the
evaporator of the dryer under any load conditions.
SETTING
The hot gas bypass valve is factory set during the test
phase. As a rule, no additional settings are needed, but
if an intervention is required, an experienced cooler
technology engineer should do this.
The screw needs to be adjusted without the load on
the dryer. Rotate the screw until the following value is
reached:
Hot gas setting: R134.a pressure 2.0 barg ( ± 0.1 bar)
5.6. Timed condensate drain
Condensate drain consists of two timers, Ton and Toff which are regulated by controller RDC 2. Ton
timer regulates the time duration of discharging and Toff regulates time between two discharges
(period). When the controller sends a signal at pin DRAIN, it activates the discharging process
immediately, which is noticed by the sound of valve being open. Condensate flows through inlet
connection and is discharged through valve and outlet connection. After the set time Ton passes, valve
closes until the time Toff passes, when new cycle begins. Cycles are continuously repeating.
Figure 3: Bypass valve
Figure 4: Thermal expansion valve