The Importance of Cooling Tower Layup

Cooling tower layup prepares an open-recirculating cooling tower system for an extended shutdown or low-use period, especially when freezing conditions are possible. The goal is simple: protect the equipment, preserve system integrity, and reduce the risk of unpleasant surprises when warmer weather returns.

A well-planned layup prevents damage to basins, piping, nozzles, valves, and fill. It also controls stagnant-water conditions that encourage microbiological growth and corrosion.

Dry Layup vs. Wet Layup

For many seasonal shutdowns, a dry layup is preferred. It removes water from the system and reduces the risk of freezing. However, a dry layup still needs proper cleaning, disinfection, and corrosion protection before the final drain. Simply opening the drain valve and walking away can leave contaminants, deposits, and untreated surfaces behind.

A wet layup may be necessary if a system might need to restart during the off-season or when complete draining is impractical. In that case, treat the system, circulate periodically, and monitor to keep chemical residuals in control. Every system is different, so confirm the right layup method before shutdown.

Six Steps for a Safe Cooling Tower Layup

The best layup programs start before the final day of operation. Use the shutdown window to reduce solids, clean the system, disinfect wetted surfaces, and apply the right layup chemistry. The following steps provide a practical framework for preparing your cooling tower for the off-season.

1. Lower cycles of concentration before shutdown. In the week before layup, adjust the conductivity set point to increase blowdown and reduce dissolved and suspended solids in the system.

2. Disinfect the system. Add a bio-dispersant and an oxidizing biocide to kill bacteria, remove biofilm, and break up microbiological fouling. Circulate for 4 to 8 hours, or as directed by your water treatment professional.

3. Drain and physically clean the tower. Remove remaining solids from the fill, basin, sump, strainers, and other accessible areas.

4. Refill and circulate. Refill the system with clean water and begin circulation so that layup treatment reaches wetted surfaces.

5. Add layup chemistry and biocide. Apply the appropriate layup chemical and a heavy dosage of non-oxidizing biocide. Circulate for 24 to 48 hours, or according to product and site-specific guidance.

6. Drain completely for dry layup. Remove water from the system, including dead legs, low points, and trapped volumes. As the system dries, pretreatment chemicals can support passivation, creating a protective oxide layer on internal surfaces.

   
   

Don’t Overlook Stagnant Zones

Dead legs, equalization piping, drain points, headers, and other trapped volumes are common problem areas during layup. Water left behind in these locations can freeze, promote corrosion, or create stagnant conditions where microbes can persist. A thorough layup plan should identify these areas in advance and confirm how they will be drained, flushed, treated, or monitored.

Plan Now for an Easier Startup Later

A clean, disinfected, and properly protected cooling tower is easier to bring back online when cooling demand returns. By taking the time to lay up the system correctly, facility teams can reduce the risk of repairs, minimize startup delays, and help extend equipment life.

Preparing your cooling tower for fall shutdown is essential. A well-executed layup process ensures that your system remains in optimal condition. This preparation minimizes issues and enhances efficiency when the system is back in operation.

Need help preparing your cooling tower for fall shutdown? Contact us to discuss your system, review your current layup process, or schedule support before the off-season begins.