Taylor-Wharton 24K w/ AutoTend - Manual (Page 28)

Control Range
CONTROL RANGE can be accessed through the menu system of the control (MENU,
6,2,3,2,2). KRYOS maintains a temperature range around the user-selected tempera-
ture. A tighter range maintains a temperature very close to the selected temperature
at the cost of greater LN
2
usage. A broad range provides more temperature variability
but the LN
2
usage is less. The range can be varied from +1º to +15ºC above and
below the selected temperature. The total range therefore, is between 2ºC (1º below
and 1º above the selected temperature) and 30ºC (15º below and 15º above the
selected temperature). When KRYOS is attempting to control by temperature, it
flashes “T.Recov” (Temperature Recovery) in the center of the bottom line.
Freeze-Guard Options
Ice crystals introduced through the supply line is the primary cause of an overfill.
Freeze-Guard is a process designed to reduce the risk of an overfill. Freeze-Guard
consists of two options to reduce the risk of a frozen valve: 1) The maximum valve
open duration can be set by the user. (VALVE OPEN DURATION) 2) The valve can
be rapidly turned on and off trying to free it up (VALVE DE-ICING). Option 2 occurs if
either the Freeze-Guard sensor detects that the valve is not fully closed or if the
control goes into a High Alarm. The special “Freeze-Guard” sensor assembly in-
cludes a plumbing “T” with an in-line thermistor which is placed in the plumbing
directly downstream from the solenoid valve. KRYOS monitors the “Freeze-Guard”
thermistor and detects if the flow of LN
2
is stopped when the valve has been com-
manded to close.
Valve Monitoring
If KRYOS detects that a flow of LN
2
is occurring even when the solenoid valve is
supposedly closed, an error message will appear on the screen indicating “Valve
Stuck Open.” To confirm, the control waits for 10 seconds after it determines that the
valve should be closed before it will indicate that the valve is stuck open.
Valve Open Duration
Valve Open Duration can be accessed through the menu system (MENU, 6,2,4,1).
This allows the user to set the maximum amount of time, which the valve will stay
open at any one time. If a fill operation exceeds the valve open duration time set by
the user, the valve closes for 15 seconds and then opens again for another cycle.
This 15 second rest period allows the solenoid valve to warm and gives the Freeze-
Guard sensor the opportunity to predict an impending overfill before it actually
overfills. The allowable settings are Disabled and 1-15 minutes.
Valve De-icing
Valve De-Icing can be accessed through the menu system (MENU, 6,2,4,2). This
feature can be turned on or off. If enabled, the control will try to free up the valve by
rapidly turning it on and off. This feature is triggered when the Freeze-Guard sensor
detects a stuck valve or when the control detects a High Alarm condition. KRYOS will
attempt to free up the valve by De-icing 5 times with a two minute delay between
tries.
Splash-Guard
Splash Guard is a process to reduce or eliminate false signals detected by the
thermistor sensor assembly. In particular this reduces sporadic valve operation when
the sensor assembly is splashed with LN
2
. When a fill operation has completed