DC4500 Cooling Tower Start Up

If you prefer, you can download this PDF as a working document for  DC4500 Cooling Tower Worksheet

The DC4500 can be programmed for a multitude of tasks for cooling tower applications.  Prior to powering up the DC4500 Conductivity Controller it is recommended that the following PRE-START UP work sheet be completed to determine required system operating parameters.

1.- Current System Conductivity __________________________________________________

2.- Desired Conductivity Set Point _________________________________________________

3.- Differential (Hysterisis) Range _________________________________________________

4.- Method of Chemical Inhibitor Feed (choose one of the following) __________________________


  1. PULSE TIMER (Flowmeter based input response).
  2. % of TIME (Continuous repeating cycle with pump ON time based on percent of the  cycle time.
  3. % of BLEED or BLOWDOWN (Amount of feed is based on a percent of the total bleed/ blowdown time).
  4. LIMIT (Chemical inhibitor feed at the same time as system bleed or blowdown).

The Feed pump can be controlled by either a powered relay output or by direct  variable speed control.  The direct power or On/Off mode requires the pump to be  connected to the ‘FEED L’ and any ‘AC NEUT’ terminal connection on the pc board.  If an LMI ‘7’ or ‘9’ series pump is being used the pump stroking speed may be  directly controlled by the DC4500 pulsed output.  The pump 4 pin connector must  be wired to the ‘PLS1 +’ and ‘PLS1 -’ terminals on the pc board.

On/Off Pump Control __________________________________________________
Variable Speed Pump Control _____________________________________________

5.- High Alarm Setting _____________________________________________________

6.- Low Alarm Setting ______________________________________________________

7.- Flow Switch Alarm activation (Yes/No) ________________________________________

8.- The DC4500 controller can be configured to control dual-chemical (biocide) pumps for water contamination/biological growth control based on a selectable 1-4 week timer. Use the table below to assist in setting up the program operating periods for the pumps when using the 1-4 week timer option.

LMI Controller Timetable

The Biocide chemical pumps may be controlled by either On/Off or Direct Variable Speedmodes. The On/Off mode supplies AC power to the pump based on relay control. The Direct Variable Speed Control mode supplies a low voltage signal to the pump for pump stroke rate control.

The terminal connections on the I/O pc board for these modes are shown:

LMI Controler Biocide Setting

9.- Biocide Lockout Timer ____________________________________________________

10.- Biocide Pre-Bleed Timer ___________________________________________________

11.- 4 mA Output ___________________________________________________________

12.- 20 mA Output __________________________________________________________

Once the operating settings and parameters have been determined by the data entered in the previous pages, the DC4500 Controller can then be programmed. Supply power to the controller. Read the conductivity and verify the accuracy using a calibrated meter and conductivity sample. Calibrate the controller as needed. See Calibration Section.

In the Main Menu, enter the required values for Conductivity, Differential, Low Alarm and High Alarm.

Go to the FEED menu screen (see FEED programming sheet in manual) and enter the required mode and settings for the chemical inhibitor pump control.

Go to the SET UP menu screen (see SET UP programming sheet in manual) and enter the Flow Alarm Option, Trip Actuation, 4 – 20 mAmp settings, Display Mode, Pulse Output Pump Control, and Control Cooling Tower.

Go to the CLOCK menu screen (see CLOCK programming sheet in manual) and enter the current day and time information as well as the number of weeks required for the repeating Biocide Pump programming.

Go to the BIOCIDE pump menu screen (see BIOS programming sheet in manual) and enter the required options for the Biocide Pumps.

Use the MANUAL OUTPUTS menu (see MANUAL OUTPUTS programming sheet in manual) to check that all controlled devices are properly connected.

This completes the cooling tower start-up.  Return the display to the ‘SYSTEM RUN’ or ‘CONDUCTIVITY Reading screen to begin operation.

The system will return to the “SYSTEM RUN” mode automatically on its own after three (3) minutes if no keys are pressed.

If you prefer, you can download this PDF as a working document for  DC4500 Cooling Tower Worksheet

Click here to go to Bleed or Blowdown Sampling Option