COOLING TOWER | Preventative Maintenance Inspections

06, May. 2024

 

COOLING TOWER | Preventative Maintenance Inspections

A building owner should ensure a regular daily/weekly and monthly preventative maintenance schedule is applied for their cooling towers and ancillary equipment throughout the year to help and ensure:

Want more information on cooling tower gearbox maintenance? Feel free to contact us.

  • The risk of Legionella is managed/reduced
  • Scale and debris build-up is managed
  • The efficiency of the tower is maintained
  • Minimizing early failure of mechanical components/electrical components 
  • Reducing corrosion within the tower and on the external surfaces
  • Reduction in downtime of the tower
  • Longevity of its intended operational life

How long do cooling towers last?

15 to 20 years is the general expectation of life for an industrial cooling tower, used in a cooling process for general office buildings, etc, before the need for replacement or extensive rebuild.

This is why a good preventative maintenance regime is extremely important, as this can sometimes extend the operational life.

We have seen cooling towers that are much older than this.

How often should cooling towers be inspected?

For preventative maintenance and depending on the component, they should be inspected daily, monthly, quarterly, semi-annually, yearly. See below.

Documentation usually required to conduct the works

The following documentation would usually be a requirement prior to any works taking place to ensure it is conducted safely and correctly:

  • Previous inspection reports
  • System schematics and layout drawings
  • Check sheets for recording the works
  • Risk assessment
  • PPE assessment
  • Method statement
  • COSHH assessment 
  • Work permits etc

Cooling Tower Maintenance Checklist and Plan

Only Engineers and Operatives who are qualified, experienced, and fully understand the design and operation of the system should complete these inspections.

Below we run through an example of the checks that would generally be conducted, any observations should be noted, advice on the needs of the remedial work and, when completed signed off. The urgency of the remedial works will depend on the criticality of any observations.

Please note: Preventative Maintenance should not be confused with Inspecting and Cleaning of Cooling Towers which can be read about in our article 'Overview | Inspecting & Cleaning Cooling Towers'.

What to check daily

  • Unusual noise and vibrations in and around the tower, will generally be from the fan
  • Unusual noise and vibrations at the condenser water pump
  • Check the water level in the basin, this can be done via the level sensor at the BMS if part of the system
  • Water quality checks

What to check monthly

  • General overview of system condition inspection
  • The general condition of the fan and motor/drive mechanism
  • Check for oil leaks in components, hoses and fittings
  • Check oil levels and add if required
  • Clean the fan motor
  • The water makeup valve is operating correctly
  • Inspect and clean the air inlet
  • Inspect and clean the tower drift eliminators
  • Inspect and clean the tower fill pack
  • Inspect and clean the hot water basin feeding the fill pack
  • Inspect and clean the spray nozzles
  • Check the spray pattern of the nozzles
  • Inspect and clean the tower basin
  • Check operation of the blowdown system
  • Check operation of the bleed water valve and system
  • Check operation of vibration switch
  • Check and clean side stream filtration/sweeper systems
  • Check operation of the chemical dosing system
  • Check and clean pipework strainers
  • Manually check the level and valve of the tower water basin and make adjustments if required to the water feed
  • Check protective finishes to surfaces of tower and components to ensure are not damaged and compromised
  • Review operation of basin heater and clean sensor if necessary
  • Check the status of system operation [set to automatic]

 What to check quarterly [3 months]

  • Check belt alignment and tightness [if fitted to motor]
  • Check fan blades for cracks, missing balancing weights, and any apparent vibrations
  • Check fan blade pitch [angle]
  • Check fan blade tip clearance
  • Review operation/signal of level sensors and clean if necessary 
  • Inspect condition of ladders/handrails/stairways/walkways etc
Cooling Tower Pre-Functional Testing Checklist [MS Word] + [MS Excel]

Here is our open copy [MS Word] of the COOLING TOWER Pre-Functional Checklist, for making life a little easier...

We have also recently formatted this checklist to [MS Excel] and included it as a Bonus for FREE. 

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What to check semi-annually [every 6 months]

  • Change oil
  • Check and tighten fan blade hub

What to check Yearly

  • Check all mounting bolts for tightness and signs of corrosion
  • Inspect all parts of the motor including oil plugs etc
  • Lubricate components
  • Inspect drive shaft not loose
  • Check for drive shaft/bush wear and tear
  • Check motor alignment on the fan

After any Extended Shutdown Checks

  • Complete all checks above

Cooling Tower Preventative Maintenance Sample Checklist [PDF] & [.doc]

To download the below document [Free] in A4-[.doc], click the below button to be taken to our shop:

FAQ

If you want to learn more, please visit our website 40 tr cooling tower.

How do you clean a cooling tower?

see our article ‘Overview | Inspecting & Cleaning Cooling Towers‘.

Evapco cooling tower maintenance checklist?

Here is a link to the Evapco checklist

SPX Marley cooling tower preventive maintenance checklist?

Here is a link to the SPX Marley checklist

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4 Ways to Perform Cooling Tower Maintenance

With the summer in full swing, performing cooling tower maintenance will keep your building comfortable for all building occupants. As cooling towers use water to remove heat from a building, they are easily susceptible to damage — which is due to their design.

According to the Centers for Disease Control and Prevention (CDC), water is sprayed throughout the tower, while air is then brought through the sides to exchange heat inside a building or facility. As a crucial component to any building or facility’s HVAC operation, ensuring the cooling tower’s health is of utmost importance. Here are 4 ways to perform cooling tower maintenance. 

Inspection

As your building/facility’s cooling tower utilizes water on a regular basis, conducting cooling tower maintenance on it should become common practice. You will want to inspect for a number of contaminants, including scale, sediment, and slime. To inspect, be sure to wear a face mask with a HEPA (high efficiency particulate air) filter and shut off fans before working, as SPX Cooling notes.

Furthermore, you’ll want to be aware of potential Legionnaires’ disease outbreaks. 

Legionnaires’ disease can quickly make its way through an office or facility if a cooling tower remains unkempt. This is because standing water/water buildup, combined with the air and heat within the cooling tower, creates a prime breeding ground for legionella — the bacteria that causes Legionnaires’ disease.  The Mayo Clinic notes that Legionnaires’ disease can lead to headaches, muscle aches, fevers of 104 degrees Fahrenheit and above, on top of cognitive issues.

With such harmful biological contaminants in the cooling tower environment, it’s best to have an HVAC expert take a look. Our trained technicians at Donnelly will be more than happy to assist.

Water Treatment

When performing cooling tower maintenance, another important aspect to consider is water treatment. Given that a great amount of water runs through the cooling tower on a regular basis, you’ll want to be aware of the water’s health. This is where water treatment comes into play. 

As water can be a site for contaminants and other dangerous impurities, making sure that you not only have the right filtration, but are also using the right chemicals to treat your water will protect your cooling tower and put your employees’ health at the forefront. According to Process Cooling, there are a number of filtration options — including screen filters, disc filters, sand media filters, and centrifugal separators. The outlet notes that the former and latter are the most common.

You’ll also want to make sure that the water’s hardness is being regulated. You can do this by using a softening resin or lime. The softening resin generally contains sodium ions, which, when coming into contact with water, will latch onto calcium and other byproducts and break it down — leaving no harmful residue behind.

Clean and Disinfect Tower Basin

Cooling tower maintenance also includes cleaning and disinfecting the tower basin. Per the CDC, you should use an EPA-registered disinfectant that contains chlorine. These can come in either liquid, pellet, or granular form. Look for calcium hypochlorite (Ca[OCl]2) or sodium hypochlorite (NaOCl), as the CDC notes.

Dispersant cleaning is also advised. Most likely, you will be leaving the disinfectant and dispersant in the cooling tower overnight — monitoring the FRC (free residual chlorine) levels every two hours or so. Drain after a 24-hour period.

Overall, dispersant cleaning should remove silt, scale, and residual biofilm in your cooling tower.

Descale Cooling Tower

Cooling tower maintenance also entails descaling. As noted, since cooling towers utilize water, many contaminants and biohazards can accumulate over time. With such buildup of lime, rust, scale, and more, your cooling tower will experience decreased efficiency and suffer long-term damage over time. You’ll also incur higher energy costs from an unkempt system.

In order to descale your cooling tower, you’ll have to shut off the water valve and shut off any chemical/non-chemical water treatment, alongside corresponding meters. Be advised that you should also clean any loose mud, rust, and other debris, too. Next, lower the water level to where the pump can still operate without cavitation and shut off fans.

After that, determine the appropriate amount and deposit the descaling solution. You may notice foaming and bubbling, which is a direct result of coming in contact with scale. Test pH levels and cycle the solution out of the system when complete.

Donnelly’s Commitment to Cooling Tower Maintenance

At Donnelly, we offer a strong team of HVAC technicians trained in handling various types of HVAC issues. Whether it’s cooling tower maintenance or mold remediation, you can always trust Donnelly to get the job done.

To learn more about our services and how we can help your commercial space, please visit our website and contact us today!

Contact us to discuss your requirements of open cooling tower. Our experienced sales team can help you identify the options that best suit your needs.