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5.4
Blowdown (A or B) Menu
The Blowdown Menu provides the following settings: Set Point, Dead Band, Time Limit, Control
Direction, HOA. The Blowdown menu will be indicated on the display by one of the following:
(The 'A' indicates that the output is being controlled automatically.)
Blowdn A
OFF
Indicates that the blowdown output is currently OFF.
Blowdn A
TIMEOUT
Indicates length of time that the blowdown output has been ON.
Blowdn A
NO FLOW
Indicates that blowdown control has been suspended because there is presently no flow past the flow
switch.
Blowdn A
1:01
Indicates the length of time that the Blowdown output has been ON.
Blowdn A
SAMPLE
Indicates the relay is in sampling stage of Intermittent Sampling
Set Point
This is the conductivity value at which the Blowdown valve is turned ON. The factory default setting for the WDB
controller is for the Blowdown output to turn on when the conductivity is higher than the set point.
Dead Band
This is the conductivity value that when combined with the set point determines when the blowdown output turns
OFF. The blowdown output will turn off when the conductivity drops below the set point minus the Dead Band. For
example: The set point is 1500 µS/cm and the Dead Band is 200 µS/cm. The blowdown output turns ON when the
conductivity reading is greater than 1500 but does not turn OFF until the conductivity drops below 1300. This
setting is not used when intermittent Sampling has been selected.
Time Limit
This menu allows you to set a maximum amount of time for the blowdown. The limit time is programmed in hours
and minutes and can be set between 1 minute and 8 hours 20 minutes. If the maximum time is exceeded, the
Blowdown valve will close and will not re-open until the "Reset Timer" menu is reset by an operator. If the time
limit is set to zero, then the valve may be open indefinitely.
Reset Timer
Only appears if the time limit above has been exceeded. Use the up or down arrow to change "N" to "Y", then press
ENTER.
This allows you to set the Normal (High Set Point) or Inverse (Low Set Point) operation of the blowdown output.
When set to High, the output turns on when the conductivity is higher than the set point. When set to Low, the
output turns on when the conductivity is lower than the set point.
Control Dir
H / L
High Set Point
Low Set Point
H O A
The "Hand Off Auto" screen allows you to select the operating mode of the blowdown output. In Hand (manual)
mode, the output is turned on immediately for a maximum of 10 minutes. If you walk away the output will return to
Auto mode at the end of that time. In Off mode the output will stay Off indefinitely. In Auto mode the blowdown
output will respond to changes in conductivity based on the set point. The HOA mode of the blowdown output is
indicated on the blowdown status lines.
