8
Non-cycling Refrigerated Dryer
MODELS D340IN, D40IN, D510IN, D680IN, D850IN, D100IN, D1190IN, D1360IN
http://air.ingersollrand.com
7.5 CONTROLS
Ingersoll Rand non-cycling dryers incorporate automatic
controls for proper operation. A refrigerant suction pressure
gauge is provided as standard equipment. This gauge
monitors the pressure of the refrigerant gas before it enters
the compressor. When the refrigeration system is running,
the suction pressure will be controlled between 76 and 85
psig.
Ingersoll Rand air-cooled models utilize a fan cycling switch
to control the condenser temperature. This switch controls
the condensing temperature by cycling the fan based on
refrigerant discharge pressure. When the unit reaches
75 psig, the fan cycling switch will run the fan until the
discharge pressure is reduced to 195 psig.
Ingersoll Rand dryers include a Hot Gas By-Pass Valve to
maintain suction pressure and temperature. This valve is
necessary during low load applications to prevent freeze-
up in the chiller section. The normal suction pressure for
no load conditions should never drop below 7 psig. *This
setting may need adjustment to match the load/ambient
conditions encountered.
*This adjustment is not a procedure covered under warranty
as it is typically required for application-specific conditions.
CAUTION
Do not rotate Hot Gas By-Pass Valve adjustment
fully clockwise. Full clockwise rotation may result in
refrigerant compressor damage. Any suction pressure
setting above 90 psig is not recommended.
For Hot Gas By-Pass Valve adjustment, note the following:
Turning the adjustment screw clockwise raises suction
pressure and exchanger temperature.
Turning the adjustment screw counter-clockwise
reduces suction pressure and exchanger temperature.
All adjustments should be made without air flow
(load) on the dryer.
For water-cooled models, a high pressure cut out switch is
positioned near the water regulating valve. The switch is
designed to open at 30 psig and close at 70 psig.
To compensate for water temperature variation, it may be
necessary to adjust the water regulating valve to maintain
a 50 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.
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ADJUSTMENT
SCREW
WATER REGULATING VALVE
FIGURE 2
7.5.1 BASIC USER INTERFACE
The Microprocessor Control display provides the user with
the operating parameters and their corresponding values.
The following illustration summarizes the keypad functions.
BUTTONS
ON / OFF
Toggles the dryer operation between “On Line” and
“Off Line” status.
EXCH SET
When depressed, will display the current High
Temperature Alarm set point in the LCD window.
While the High Temperature Alarm set point is
displayed, the up and down arrows may be used to
increase or decrease the 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.
°F / °C
Toggles the LED temperature indicators between
Fahrenheit and Celsius units of measure.
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7.0 PRINCIPLES OF OPERATION
