7.6.2 EXCHANGER TEMPERATURE SET POINT AND ALARMS
The Controller allows the user to configure the dryer’s
Exchanger Temperature Setpoint to operate according to site
conditions. The Controller is shipped from the factory with the
exchanger temperature having a default value of 38 deg.
7.6.3 ADJUSTING SET POINTS
Accessing and manipulating the Exchanger Temperature
Setpoint is accomplished as follows.
7
Nirvana Cycling Refrigerated Dryer Models 200-400
http://air.irco.com
7.0 PRINCIPLES OF OPERATION
The alarm names and a brief description of each are described in
detail below.
HIGH TEMPERATURE ALARM
When the thermal mass (glycol) temperature reaches the alarm set
point, the alarm will be activated. This alarm condition may not
necessarily damage the dryer when subjected to long-term exposure.
It may, however, have a significant impact on downstream processes
and thus should be investigated upon detection. Note that this alarm
will not shut down the dryer. This alarm will activate the remote alarm
contact and reset automatically once the alarm condition is rectified.
LOW TEMPERATURE SAFETY ALARM
If the dryer chiller temperature falls below the factory set point, the
alarm routine will activate. This alarm condition may cause damage to
the dryer when subjected to continuous or long-term exposure. Note
that this alarm will shut down the dryer after a response time delay.
This alarm will activate the remote alarm contact and reset
automatically once the alarm condition is rectified.
7.6.5 ALERT MESSAGES
The Controller features the following readouts to communicate the
status of the dryer’s operation.
EXCH.
SET
Pressing EXCHANGER SETPOINT button will change the display to
show the current setpoint.
36
Pressing the UP or DOWN arrows modifies the EXCHANGER
SETPOINT in one degree increment.
37
Pressing the UP or DOWN arrows modifies the EXCHANGER
SETPOINT in one degree increment.
38
The Controller accepts the last setpoint. After 5 seconds, the readout
will return to displaying the current Exchanger Temperature.
38
a
CAUTION
Do not set the Exchanger Temperature greater than 50 deg.F. Running
dryer at an Exchanger Temperature higher than 50 deg.F may damage
refrigeration system.
7.6.4 ALARMS AND THEIR FUNCTIONS
The Controller indicates critical alarms to alert the user of an
out of tolerance condition. Once each alarm condition is
detected, the appropriate LED indicator will illuminate and the
remote alarm contact will close.
Alarm Display Alarm Set Point
HIGH TEMPERATURE
ALARM
HI TEMP ALARM EXCH SETPOINT + 10 °F
LOW TEMPERATURE
ALARM
LOW TEMP ALARM 28 °F
Indicates a probe failure. This condition
is usually caused by a probe being
unplugged, damage to the probe lead or
a defective probe.
PF
Indicates that the refrigerant compressor
will not start until the end of a three
minute safety delay. The display of “cd” is
immediately followed by the number of
minutes left in the delay. This is a normal
function of the controller and not a fault
indication.
cd
7.6.6 START MODES
The NCV200-400 dryers are capable of starting in one of the
following start modes:
7.6.6.1 Manual Mode
After power is supplied to the dryer, the LCD display will
indicate the chiller temperature as well as the time remaining
for the safety delay. Once the delay has timed out,
depressing the On/Off button will permit the refrigeration
system to operate. Should the chiller temperature be greater
than the set point, the refrigeration system will energize.
Should the chiller temperature be below the set point, the
refrigeration system will remain off until the chiller temperature
rises to the setpoint.
7.6.6.2 Remote Mode (Optional)
This mode of operation allows the user to control the dryer
remotely and requires the installation of a customer-supplied
contact. With power applied to the dryer and once the safety
delay has timed out, the dryer will start once the remote switch
is closed. In addition, this mode of operation still permits
manual control of the dryer via the On/Off pushbutton on the
local control panel. Note that if the dryer was turned "On"
from the remote switch and then turned "Off" via the local
control panel, the remote switch must be turned "Off" and then
"On" to reinstate the dryer.