PRODUCT USER MANUAL SECTION 3
44
3.10.5 CRANKCASE HEATER
3-Phase dryers are equipped with an electric
crankcase heater. The heater provides preliminary
pre-heating of the refrigerant compressor to
evaporate liquid refrigerant possibly condensed in
the crankcase. This will prevent liquid shock that can
damage the compressor.
3.10.6 REFRIGERANT CIRCUIT REGULATION IN
RN-0005 TO RN-0050 MODELS
The liquid refrigerant is injected into the evaporator
by a metering device while maintaining the
refrigerant in the evaporator at a constant pressure.
This constant pressure corresponds to a stable
evaporation temperature adjusted as close to 32°F
as possible.
3.10.7 REFRIGERANT CIRCUIT REGULATION IN
RN-0075 – RD-6000
1. The liquid refrigerant is injected into the
evaporator through a metering device trying
to maintain the refrigerant in the evaporator
at a constant pressure
2. The evaporating pressure is kept constant by
a controlled injection of hot gas from the
high-pressure side into the low-pressure
section of the circuit through a hot gas by-
pass valve. This constant pressure corre-
sponds to a stable evaporating temperature
adjusted as close to 32°F as possible.
3. The mixture of hot gas from the by-pass
valve and cold gas from the evaporator is
called superheat and is adjusted at (50 ± 5)
°F.
3.10.8 CONDENSATE DRAIN—TRAP
ASSEMBLY
Dismantling the drain is easy because it can be
isolated from the air circuit under pressure with a ball
valve. Always isolate the drain before disassembly.
3.10.9 DRAIN MAINTENANCE
Ball Valve isolation option is available only in dryers
with capacity 35 CFM and above. For dryers with
capacities less than 35 CFM, the unit must be
completely depressurized before any attempt is
made to clean the condensate separator and the
drain trap.
3.10.10 HEAT EXCHANGER, MODULAR DESIGN
The dryers are equipped with compact, modular
design heat exchangers. This assembly has been
specially designed to dry compressed air and
consists of:
1. An air/air heat exchanger which pre-cools
the entering hot air with the exiting chilled air.
2. An evaporator which is an air/refrigerant heat
exchanger which cools down the com-
pressed air
3. An integral separator that separates the
moisture from the air stream at the coldest
point. Maximum condensation of moisture
occurs at the coldest point and it is at that
exact junction that the moisture is removed
and drained.
3.10.11 DEW POINT INDICATOR
The Dew point indicator is a standard on all dryer
models and is located in the control panel and
provides a reading of the pressure dew point (PDP)
3.10.12 TEMPERATURE SWITCH—
RD400 AND UP
Located inside the dryer, this optional temperature
switch is adjustable from 32~95°F (0 ~35°C).
3.10.13 MICROPROCESSOR DEVICE
This device is supplied on models equal and greater
than RD400 3 phase dryers. The Microprocessor
allows the dryer to save energy when there is no flow
in the dryer. It is possible to monitor major dryer
failures on the Microprocessor. It allows the
operators to monitor the following:
• Evaporation temperature
• Inlet air temperature
• Ambient temperature
• Refrigerant gas high and low temperatures
• Fan is working properly
• Compressor is working properly
• Condenser is blocked
• Power Phases are correctly connected
• Drain function
• Total working hours
• Total economy hours
• Real date and time
Microprocessor can be remotely controlled and any
alarm contacts can be connected to any external
devices.
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