Cooling Tower Lay-up (winter shutdown procedure)

Pre-shutdown Procedure:

  1. Five days before shutdown, gradually lower the specific conductivity to a point below the minimum of the control range.

  2. 48 hours prior to shutdown, add a surfactant. Wait 2 to 3 hours and add a heavy dosage (2 times normal feed rate) of non-oxidizing biocide.

  3. Maintain the corrosion inhibitor concentration at the upper control range. Since you are removing water to bring the conductivity down, this will require an increase in the feed rate of the corrosion inhibitor.


  1. Shut the system down, drain, and inspect. Clean and flush the tower. Inspect and clean the tower decks for deposits and debris.

  2. Refill with fresh water.

  3. Dry Lay-up: Add lay-up chemical and a heavy dosage of non-oxidizing biocide (2 times normal feed rate) and circulate 8 to 24 hours. Drain the system completely

  4. Wet Lay-up: Add a closed loop treatment product at the normal suggested control range. Add a heavy dosage (2 times normal feed rate) of non-oxidizing biocide to the same water. Circulate for 8 to 24 hours. Drain lines to below roof level to protect against freezing, if applicable.

  5. Remove, clean, and store pH and conductivity probes per manufacturer's recommendations.

Spring Startup:

  1. Refill with fresh water and begin circulating.

  2. Shot feed a surfactant at 50 to 100ppm. Wait two hours and add a heavy concentration (2 times normal feed rate) of non-oxidizing biocide.

  3. Initiate the normal corrosion inhibitor program.

  4. For the first week, maintain conductivity levels at or below the lower control range limit.

Hydro-Logic Incorporated
340 South Broadway
Gloucester City, NJ 08030
Phone: (856) 742-8300
Fax: (856) 742-7623
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