DC4500 Bleed or Blowdown Sampling Option

Operating Mode

The DC4500 Conductivity Controller can be configured to operate in one (1) of two (2) different operating modes for conductivity bleed or blowdown:

  1. Timed Conductivity Blowdown Sampling
  2. Continuous Conductivity Blowdown Sampling (Standard Method)

The Continuous Conductivity Bleed/Blowdown is the most commonly used method. When the conductivity is above a setpoint, a valve is opened and water is bled off until the conductivity is below the setpoint minus the hysteresis. All DC4500 Controllers are factory set for this method of control.

In the ADVANCED Menu, the operator is offered the option of changing this to a “TIMED SAMPLING” method of bleed control.

In the “TIMED SAMPLING” mode, the conductivity is only looked at periodically. If the conductivity is high, the valve will be opened and the water bled off until this conductivity is brought back to the desired setpoint. This is done when the probe is installed on the drain line itself. It allows for minimal piping installation.

The programmed settings for this method are 1) sampling time, and 2) sampling duration.

  • SAMPLING TIME – is the amount of time in between active conductivity readings. If the conductivity is above the setpoint during this time, the unit will not bleed.
  • SAMPLING DURATION – At the end af the Sampling Time, the bleed valve will automatically open up and start bleeding off water. The unit will bleed water off for the entire sample duration time. This is done to get a good clean sample near the probe. At the end of the sample duration the valve will be closed if the conductivity is below the setpoint, or held open if the conductivity is above the setpoint. It will then continue to bleed until the setpoint is reached.

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