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Commercial HVAC, Preventive Maintenance Agreements

HVAC Cooling Tower Maintenance Checklist

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Last Updated on May 18, 2017


THIS CONTENT HAS BEEN REVISED as per the new NYC cooling tower legislation. See the updated article:   UPDATE: Cooling Tower Maintenance Checklist for NYC

Following the Legionnaires’ Disease outbreak in New York City this past summer, there is a great deal of concern and uncertainty about what’s required for proper cooling tower maintenance. As a business owner, you want to keep your employees and customers safe from deadly bacteria. And if you’re in New York City, you must make sure you stay in compliance with NYC Health Department regulations.

What’s happening with New York’s cooling tower maintenance legislation

Back in August, the New York City Council passed new legislation that requires the registration, inspection and disinfection of all cooling towers as a preventative measure against Legionnaires’ Disease. The new law requires building owners to register all cooling towers with the city, and also register any new cooling towers before putting them into use. The NYC Health Commissioner has also issued an order requiring all cooling towers to be inspected by an environmental consultant and then disinfected.

In addition, New York State is now requiring the testing and inspection of cooling towers as well as implementation of a cooling tower maintenance plan. Owners of buildings with a cooling tower are required to implement a maintenance plan by March 1, 2016.

Here are some resources to learn more about the new regulations around cooling tower maintenance:

We are hearing that new NYC regulations are currently being developed that specify more detailed requirements for cooling tower maintenance and water treatment. Keep an eye or for more information about these regulations in the coming months. In the meantime, here’s what you need to know about best practices for cooling tower maintenance, so you can keep building occupants safe and your water-cooled HVAC system performing reliably and efficiently.

The Components of a Cooling Tower Maintenance Plan

Monthly water treatment

  • Once a month, the water in your cooling tower needs to be treated with a corrosion inhibitor and biocides to insure that bacteria levels are low.
  • If tests reveal bacteria levels that are too high, your cooling tower will need to be professionally disinfected.

Water testing

  • The exact test that will be required by law are still being defined, but Legionella testing is recommended at least once per year.
  • New York City may also require bacterial testing on a quarterly basis.

Cooling tower inspection

  • Cooling towers need to be regularly inspected for the presence of dangerous bacteria as part of a water treatment plan.
  • The components, including nozzles, basins and drains, need to be inspected for scale buildup and corrosion as part of a preventative HVAC maintenance plan.

Deep cleaning and winterizing

  • Seasonal cooling towers need a deep cleaning of all interior surfaces of the tower at least once per year, and 12-month cooling towers should be cleaned twice per year.
  • The process involves adding cleaning chemicals and circulating for 6 to 24 hours, depending on the system and usage, then draining and flushing out the system.
  • Pressure washing and vacuuming may also be needed, with special attention to basins, nozzles and spray tree, as well as cleaning the fill material.
  • Seasonal cooling towers need to be drained and sanitized at the end of the cooling season. Also, be sure to drain water from pipes to prevent freezing up.
  • HEADS UP: we have heard that the new cooling tower maintenance regulations may require sanitizing a cooling tower that is being replaced before disposing of it.

System maintenance

  • Mechanical components such as fans, motors, belts and gears need to be cleaned, adjusted and replaced if worn.
  • Electrical components such as wiring and capacitors need to be checked and replaced if needed.

Why cooling tower maintenance is so critical

Beyond complying with regulations, there are several critical reasons why you don’t want to neglect cooling tower maintenance.

The last thing you want to deal with as a business owner is the threat of Legionella or other illness caused by the growth and spread of bacteria in your cooling tower. Implementing monthly water treatment with biocides as part of regular cooling tower maintenance will eliminate that concern and keep your building occupants safe.

Reliable and efficient operation of your HVAC system
When you neglect cooling tower maintenance, all the accumulated mineral scale, mud, dirt and debris will eventually get into your air conditioning condensers. Scale buildup can also cause blockages and uneven water over the fill media. When that happens, it impedes the operation of the system by forcing it to work harder to cool your space. Not only will you experience cooling issues, but you can only let it go for so long before the system will break down. At that point, you will be faced with repair bills in addition to cooling tower maintenance.

Related article: Air Conditioning Maintenance Doesn’t Cost. It Pays.

Energy savings
Did you know that when your system water temperature is raised by as little as 2°F, it can cost you as much as 6 percent more in energy consumption? That’s because your chiller and your cooling tower fan need to work harder and run longer trying to get to the required leaving water temperature, which uses more energy.


Not sure your current HVAC maintenance company is doing your cooling tower maintenance according to regulations and these best practices? It may be time to look into a preventative maintenance contract that’s better aligned with your requirements, and from a company that can be trusted for quality work. Learn more about how to select the right maintenance agreement for your business with our free guide to HVAC Preventive Maintenance Contracts: How to Find The Right One For Your HVAC Infrastructure.

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