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11.13 Condensate separator
The cold air exiting the evaporator goes through the hi-efficiency condensate separator featuring a stainless steel
mesh. As the condensate transported by the air gets in contact with the mesh net it is separated and expelled by
means of the draining device. The resulting cold and dry air is then conveyed into the air-to-air heat exchanger.
The mesh type mist separator offers the benefit to be highly efficient even with variable flow rates.
11.14 Hot-gas bypass valve
At partial load, the valve directly returns a part of the hot gas to the suction line of the refrigerating compressor. The
evaporation temperature and the evaporation pressure remain constant.
ADJUSTMENT
The hot gas by-pass valve is adjusted during the manufacturing testing phase.
As a rule no adjustment is required; anyway if it is necessary the operation
must be carried out by an experienced refrigerating engineer.
WARNING
the use of ¼" Schrader service valves must be justified by a real malfunction
of the refrigerating system. Each time a pressure gauge is connected, a part
of refrigerant is exhausted.
Without compressed air flow through the dryer, rotate the adjusting screw
(position A on the drawing) until the following value is reached:
Hot gas setting :
11.15 Refrigerant pressure switches LPS – HPS
To ensure the operational reliability and the protection of the dryer, a series of pressure switches are installed in the
gas cycle.
LPS : Low-pressure guard on the suction side of the compressor, which is triggered when the pressure drops below
the predetermined value. The values are reset automatically as soon as the nominal conditions are re-
established.
Calibrated pressure :
HPS : The high-pressure control unit on the discharge side of the compressor is activated when the pressure
exceeds the predetermined value. It has a manual reset button on the control itself.
Calibrated pressure :
11.16 Safety temperature switch TS
2
1
11.17 Compressor crankcase heater
At low temperatures, the oil can more easily intermix with the refrigerant gas. When the compressor starts, oil can be
drawn into the refrigeration cycle, leading to "hydraulic shocks". To prevent this, a resistance heater is installed in the
suction side of the compressor. When the system is connected with the electric mains and the compressor is idle, the
heater will keep the oil at the correct temperature.
This heater is controlled via a temperature switch which prevents the overheating of the oil.
Note: The heater must be connected to the mains at least a few hours prior to the start-up of the refrigerating
compressor.
DRYPOINT® RS 25-1010 HP50
R134.a pressure 2.0 barg (+0.1 / -0 bar)
R407C pressure 4.5 barg (+0.1 / -0 bar)
R 134.a
Stop 0.7 barg - Restart 1.7 barg
R 407 C
Stop 1.7 barg - Restart 2.7 barg
R 134.a
Stop 20 barg - Manual reset (P<14 bar)
R 407 C
Stop 30 barg - Manual reset (P<23 bar)
To ensure the operational safety and the soundness of the dryer, a safety
temperature switch (TS) is installed at the refrigeration cycle. In the event that the
pressure gas temperature is too high, the sensor of the temperature switch will
stop the refrigerating compressor to prevent the pressure gas temperature getting
too high.
The temperature switch is reset manually, but only when the normal operating
conditions are reached again. Unscrew the cover (see pos. 1 in the illustration)
and press the reset button (see position 2 in the illustration).
TS setting :
temperature 113 °C (+0 / -6 °K)
Technical description
A
4 mm
5/32 in.
-
+
31
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