LMI

Controller DC4500

Cooling Tower Controller

The DC4500 is a bleed and feed cooling tower controller with dual biocide timers. Standard features include; four feed modes (Feed & Bleed, % of Time, % of Bleed, Flow meter Pulse), intermittent or continuous sampling, uS or PPM display, flow totalizer, manual test modes, temperature display, biocide cycle of 7, 14, or 28 days, biocide lockout, and conductivity or time-based biocide pre-bleed. Programming is simple and is accomplished with only three keys. The backlit liquid crystal display and LEDs provide a visual indication of operating conditions and equipment status.

  • Dual biocide control
  • Multiple inhibitor feed modes
  • 0 – 20,000 ìS range
  • Solenoid or motorized valve control
  • Open- / closed-loop system programming
  • 4 – 20 mA output [programmable]
  • Built-in equipment test circuits
  • Backlit LCD display

BLEED or BLOWDOWN of system water by valve control can be based on several set point options:

      • Conductivity set point
      • Hysteresis delay (lower than set point) to avoid valve operation chattering
      • Rising or falling conductivity trip points

FEED of chemical (inhibitor) can be based on four (4) different methods and the pump control can be either On/Off or externally-triggered Variable Speed:

      • FEED at the same time system BLEEDS (lockout timer limits maximum FEED time)
      • FEED time calculated as a percentage of total BLEED time
      • FEED based on a timed cycle (pump is on for a percentage of this timed cycle)
      • FEED based on flow meter input

DUAL BIOCIDE chemical addition may be accomplished by the use of two (2) individually programmable Relays or optocoupler outputs. These outputs provide control of two individual chemical addition pumps based on the following options:

      • On/Off or externally-triggered Variable Speed pump control or BOTH for two pump/TIMER operation
      • 28-DAY programmable timer (1, 2, 3, or 4 week selectable cycle)

ALARM indicators and relay outputs are energized based on the following conditions:

    • HIGH conductivity set point is reached
    • LOW conductivity se point is reached
    • NO FLOW condition exists (flow switch must be installed)

  • Probes
  • Flow Switch Assemblies
  • Actuators
  • Extension Cable Assemblies
  • Replacement Parts