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Control Operation During Programming
The control will only enter the Program Mode with the valve in Service. While in the Program Mode, the control will
continue to operate normally, monitoring water usage and keeping all displays up to date. Control programming is stored
in memory permanently, eliminating the need for battery back-up power.
Meter Immediate Control
A meter immediate control measures water usage and regenerates the system as soon as the calculated system
capacity is depleted. The control calculates the system capacity by dividing the unit capacity (typically expressed in
grains/unit volume) by the feedwater hardness and subtracting the reserve. Meter Immediate systems generally do not
use a reserve volume. However, in twin tank systems with soft-water regeneration, the reserve capacity should be set to
the volume of water used during regeneration to prevent hard water break-through. A Meter Immediate control will also
start a regeneration cycle at the programmed regeneration time if a number of days equal to the regeneration day
override pass before water usage depletes the calculated system capacity.
Meter Delayed Control
A Meter Delayed Control measures water usage and regenerates the system at the programmed regeneration time after
the calculated system capacity is depleted. As with Meter Immediate systems, the control calculates the system capacity
by dividing the unit capacity by the feedwater hardness and subtracting the reserve. The reserve should be set to insure
that the system delivers treated water between the time the system capacity is depleted and the actual regeneration
time. A Meter Delayed control will also start a regeneration cycle at the programmed regeneration time if a number of
days equal to the regeneration day override pass before water usage depletes the calculated system capacity.
Time Clock Delayed Control
A Time Clock Delayed Control regenerates the system on a timed interval. The control will initiate a regeneration cycle
at the programmed regeneration time when the number of days since the last regeneration equals the regeneration day
override value.
Day of the Week Control
This control regenerates the system on a weekly schedule. The schedule is defined in Master Programming by setting
each day to either “off” or “on.” The control will initiates a regeneration cycle on days that have been set to “on” at the
specified regeneration time.
Control Operation During a Power Failure
The SXT includes integral power backup. In the event of power failure, the control shifts into a power-saving mode. The
control stops monitoring water usage, and the display and motor shut down, but it continues to keep track of the time
and day for a minimum of 48 hours.
The system configuration settings are stored in a non-volatile memory and are stored indefinitely with or without line
power. The Time of Day flashes when there has been a power failure. Press any button to stop the Time of Day from
flashing.
If power fails while the unit is in regeneration, the control will save the current valve position before it shuts down. When
power is restored, the control will resume the regeneration cycle from the point where power failed. Note that if power
fails during a regeneration cycle, the valve will remain in it’s current position until power is restored. The valve system
should include all required safety components to prevent overflows resulting from a power failure during regeneration.
The control will not start a new regeneration cycle without line power. If the valve misses a scheduled regeneration due
to a power failure, it will queue a regeneration. Once power is restored, the control will initiate a regeneration cycle the
next time that the Time of Day equals the programmed regeneration time. Typically, this means that the valve will
regenerate one day after it was originally scheduled. If the treated water output is important and power interruptions are
expected, the system should be setup with a sufficient reserve capacity to compensate for regeneration delays.
