In the HVAC world, the beginning of fall represents a potential for reduction in cooling tower capacity needs.
If you work with facility management, you may be thinking of shutting down all or part of your cooling tower equipment. Here are some best practices.
Why is drying out your tower important?
Improperly treated cooling towers are prone to corrosion, scale, and biological growth. Rain and snow brought by the cold season increase humidity and, consequently, the formation of threats to your equipment. Proper shut-down helps prevent trouble when it’s time to start-up the unit again.
We know that you don’t want to risk all the good work you’ve done maintaining the cooling tower during summer, so here are some good step-by-step tips and reminders for you:
- Increase the blowdown to reduce solids in the system a couple of days before the shut-down.
- The day before the shut-down, double the amount of biocide and recirculate for at least 4 hours.
- If you have a crossflow cooling tower, sweep and clean the hot water distribution basin and nozzles while the system is operating. If you have a counterflow cooling tower, remove drift eliminators and observe nozzle performance while the tower is running. If nozzles are clogged, turn the water flow off and clean the nozzles.
- Wash out the tower fill and the basin, including the sump
- Clean all the strainers
- Isolate the cooling tower controllers without unplugging from the power source
- Refill the tower system
- Vent all chillers and close the vents
- Add extra water treatment to the tower and recirculate the system for at least 8 hours through ALL pumps
- Completely drain the system to the lowest point
- Flush the chemical feed pumps
- Brush the chiller condenser tubes and store the chiller without the end bells so air can flow through the tubes freely.
Remember to repair or replace any parts damaged by corrosion, to treat ALL surfaces with a biocide, and to leave all drain and bleed valves open for the season. I know it sounds like a lot of work, but OSHA guidelines indicate that cooling towers should be cleaned twice each operating year, and that's the perfect time to do so.
It is also recommended to schedule an inspection with a professional cooling tower service provider once the cooling tower is cleaned, which helps identify any potential problem that you may face during winter or at the beginning of summer. Service technicians will look for wear and tear of structure and parts, and also for signs of corrosion and leaks.
If your operation requires cooling tower(s) to be running during winter, make sure that your heat tray(s) and basin heater(s) are working properly PRIOR to go to freezing conditions in order to prevent frozen pipes and ice formation in the cold water basin(s).
SPX Marley, leading cooling tower manufacturer, developed a seasonal downtime guide with golden tips. Click below to download this handy resource.