Analytical Instrumentation

Cooling tower start up procedure

Cooling towers are installed in factories to eject waste heat to atmosphere. As it is an important task to function, it should be given great care before starting the industrial process.

The significant cooling tower start-up processes are noted here.

Cooling Tower Start-up Procedure:

Start up procedure includes 3 main steps: Cleaning, Inspection, start-up.

Cleaning:

  • Drain the cold water basin with the strainer in place.
  • Clean & inspect the fan deck
  • Remove dirt and debris from the fan guards. Inspect & clean all spray nozzles.
  • Clean & inspect the mechanical components, such as the fan and motor.
  • Flush the cold water basin to remove any accumulated dirt & debris
  • Remove, clean, & replace the cold water basin strainer.

Inspection:

  • Perform external equipment inspection. Check for leaks, corrosion and any harm to the structure.
  • Perform inner equipment inspection. Check for anything uncommon like harm to structural or mechanical components.
  • Inspect piping connections.
  • Thoroughly inspect the fan for any damage.
  • Verify proper fan tip clearance.
  • When starting the season or after extended shutdown, inspect the insulation of the engine with an insulation tester before the motor start up.
  • Check and adjust the tension of the belt or inspect the oil level of the gear drive.
  • Check for free operation of the float-operated make-up valve.

Start-Up:

  • Before starting, lubricate the screw adjusting engine base and the bearings of the fan shaft. Bearings are lubricated before delivery at the original start-up. However, re-lubricate the bearings if the device has been idle for more than three months.
  • Check that the make-up valve operated by the cabinet boat operates freely. Monitor the water level closely and adjust during the first 24 hours of operation as needed.
  • Adjust the flow balancing valves for the top inlets only to equalize the flow to the warm water reservoirs.
  • For multi-cell arrangements, balance the ow between the cells to achieve even distribution of water.
  • For multi-cell arrangements, balance the ow between the cells to achieve even distribution of water.
  • Adjust the valve in the bleed row of the tower by closing or opening the valve to obtain the required bleed rate.
  • Check the heat transfer segment of the nozzles.
  • Execute one of the following biocide therapy programs during the operation of the circulating pump and before running the fans units: resume biocide therapy (or as suggested by water treatment provider) that was used before shutdown.
  • Only operate the pump while retaining the maximum recommended residual of biocides for a adequate period as suggested by the water treatment provider. Start fan only after completion of this therapy period.
  • Check the pH of the circulating water and, if necessary, adjust it to 7.0-7.6 pH. Then, running the pump only, treat the system with sodium hypochlorite (or as recommended by the water treatment provider) to maintain a free chlorine (as Cl) level of 4 to 5 mg / l (ppm) over a six-hour period.
  • Briefly energize the fan engines for original start-up and note the direction of rotation. The fan should rotate in the direction shown on the fan cowl by the arrow.
  • To check for any abnormal noise or vibrations, run the fan in manual mode for several minutes.
  • Check that the starter involves a 15-second delay when switching from elevated to low speed.
  • Check the operation of the vibration cut-out switch.
  • Check the current and voltage of all three stages of the fan engine with a thermal load on the tower under hot ambient circumstances once the cooling tower is in operation.

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