Taylor-Wharton LS Series - Manual (Page 5)

Controller Features Level LN
2
Controllers
The controller is designed to maintain the LN
2
level in the
unit within a user-defined range. The LN
2
level will be
maintained between the low level sensor and the high level
sensor. When the liquid level reaches the low level sensor,
LN
2
will be added to the refrigerator until it reaches the high
level sensor.
Basic Operation
1.) Automatic Fill: The control will open the solenoid
valve automatically when the liquid level falls below the
Low Level Sensor. It will continue filling until the High
Level Sensor is covered by liquid.
Manual Fill: The Start Fill button can be pressed at
any time and the solenoid valve will open. If the liquid
level is between High Level Sensor and the Low Level
Sensor, the solenoid will stay open until the Stop Fill
button is pressed or until the liquid level covers the
High Level Sensor. If the liquid level is above the High
Level Sensor, the solenoid valve will stay open while
the user presses the Start Fill Button but will close
when the user releases the button.
Please Note: The maximum time that the
valve will stay open when the liquid level is
above the High Level sensor is one
minute. The user can open the valve again
by simply releasing and then pressing the
Start Fill button again.
Alarm Conditions: An alarm condition occurs when
a sensor problem develops or the supply tank runs
low on LN
2
. When an alarm condition does occur, the
appropriate light on the front panel flashes and an
audible alarm is activated.
Testing the front panel lights: To test all the lights on
the control except the Filling LED, press the Stop Fill &
Mute button and hold for 8 seconds.
Testing the Remote Alarm: To test the remote alarm,
press the Stop Fill & Mute button and hold for 13
seconds (5 additional seconds after testing the lights,
or unplug the power supply from the wall.)
Remote Alarm Jack: The remote alarm relay has a
set of “dry contacts” capable of carrying 5 amperes
current at 30 volts D.C. The relay is “normal” during
any alarm condition. The remote alarm is triggered 30
minutes after an error condition occurs. The remote
alarm will be reset when the error condition is cor-
rected. Pins 1 and 2 are closed in normal operating
condition while pins 2 and 3 are open in a remote
alarm condition. See Figure 8.
DESCRIPTION OF FRONT PANEL
Key Lock: This turns the control On/Off. Turning the Key to
the 3 o’clock position provides power to the control while
rotating the key 12 o’clock position turns the control off.
Start Fill: This button opens the solenoid valve and allows
LN
2
to flow into the freezer.
Stop Fill & Mute: This button closes the solenoid valve and
stops the flow of LN
2
into the freezer. This button also
silences the audible alarm.
Filling LED: Lights green to indicate that the solenoid valve
is open.
LN
2
Level LED: Lights red to indicate that the liquid level is
above the high level sensor. Lights green to indicate that
the liquid level is between the low level sensor and the high
level sensor. Lights yellow to indicate that the liquid level is
below the low level sensor.
Please note: The LED will not light if the high level
sensor is submerged in LN
2
while the low level
sensor is located in gas. The only time that this can
occur is if the sensors are installed backwards.
Sensor Fault LED: Lights red to indicate that a sensor fault
has occurred. A sensor fault can be either an open circuit or
a short circuit in the sensor assembly.
Low LN
2
Supply LED: Lights red to indicate that the LN
2
supply is low. This is triggered when the liquid level does
not reach the high level sensor within 1 hour of opening the
solenoid valve.
24VAC Power Remote Alarm 24VAC Solenoid Valve Sensor Assembly
Electrical Supply Connections For LS6000