Thermal Mass Circulating System; Controls; Basic User Interface - Ingersoll Rand 200 Manual Del Operador

7.5 THERMAL MASS CIRCULATING SYSTEM

The thermal mass fluid in a Ingersoll Rand Nirvana™ Cycling dryer is
continuously circulated in a closed pump loop system. Referring to
Figure 1 and following the dashed "
removed from the fluid in the evaporator by the refrigeration system.
The thermal mass reservoir is sized to minimize refrigeration cycles
during reduced air load periods. The thermal mass fluid is pulled from
the bottom of the reservoir and pumped through the chiller, removing
heat from the air and then returned to the evaporator. The pump utilized
on the Ingersoll Rand Nirvana™ Cycling dryer is a maintenance-free,
quiet cartridge circulator pump similar to those used in residential water
systems. While the refrigeration system cycles on and off based on
loading conditions, the circulating pump runs continuously to maintain
flow through the chiller at all times. Note that when the power switch is
set to the off position, the circulating pump will not operate.

7.6 CONTROLS

The Ingersoll Rand NVC200-400 Series dryers incorporate automatic
controls for proper operation. The thermal mass fluid temperature is
maintained by a microprocessor control that monitors the temperature
and cycles the refrigeration system in response to varying air flow and
temperature. Upon an increase in the temperature of the thermal mass
fluid, the refrigeration compressor is cycled on. When the fluid is cooled
to two deg.F below its control set point, the refrigerant compressor is
cycled off. The thermal mass fluid functions as a thermal storage mass
in the NVC Series dryer.
A low pressure cut out (LPCO) switch is provided for all NVC series
dryers. This switch is factory set to open at 20 psig. If the refrigerant
suction pressure draws below 20 psig, the LPCO opens to shut off the
refrigerant compressor. Once the switch has opened, it will prevent the
compressor from running until the suction pressure rises above 60 psig
and the LPCO has been manually reset.
All water cooled units come with a high pressure cut out (HPCO) switch.
This switch is set to open at 320 psig and close at 270 psig. To
compensate for water temperature variation, it may be necessary to
adjust the water regulating valve to maintain a 250 psig discharge
pressure. Adjustment can be done by rotating the adjusting screw
counterclockwise for an increase in discharge pressure. For conditions
where low water temperature and/or high water pressure are expected
it is advisable to install a water pressure regulator ahead of the
condenser.
ADJUSTMENT
SCREW
FIGURE 2
WATER REGULATING VALVE
6
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7.0 PRINCIPLES OF OPERATION
" line, the heat is
THERMAL FLUID
Nirvana Cycling Refrigerated Dryer Models 200-400
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7.6.1

BASIC USER INTERFACE

The Controller provides the user with information about the
dryer's operation and alarms.
The following illustration summarizes the keypad functions.
BUTTONS
• ON / OFF
Toggles the dryer operation between "On Line" and "Off Line" status;
Energizes glycol pump. Note that the refrigeration system will operate based
on temperature.
• EXCH SET
When depressed, will display the current exchanger set point in the LCD
window. While the exchanger set point is displayed, the up and down arrows
may be used to increase or decrease the exchanger set point temperature.
• ALARM RESET
Pressing once clears the local alarm indication and de-energizes the remote
alarm contact. Should the alarm condition persist, the alarm will return after
the alarm inhibit time has expired.
• % SAVINGS
Depressing once changes LCD display to indicate ratio of refrigeration system
running time vs. total dryer ON time.
• °F / °C
Toggles the LED temperature indicators between Fahrenheit and Celsius units
of measure.
• + / -
Allows user to modify set point values. Set point values cycle through a fixed
range.
LIGHTS
• LCD Display
Displays exchanger temperature during normal operation. Also used to
display exchanger temperature set point, alarm condition and timing functions.
• SYSTEM ENERGIZED
Indicates when power is applied to unit.
• DRYER ON
Illuminated when the On/Off switch has been pressed to place the unit in
operation. The refrigerant system may start at any time when the light is on.
• REFRIGERATION COMPRESSOR ON
Indicates that the refrigeration system is operating.
• DEGREES F / DEGREES C
Indicates the temperature units of measure.
• HIGH TEMP ALARM
Indicates that the exchanger temperature has risen to 10°F or 5°C above the
exchanger temperature set point.
• LOW TEMP ALARM
When activated, indicates that the exchanger temperature has dropped below
29°F or -2°C. This condition stops the compressor. The compressor will not
restart until the temperature has risen two degrees above exchanger set point.