Regular inspection of HVAC systems is vital to ensure they are functioning well, are in good condition, and ready to deliver dependable service in the coming year. An annual inspection of evaporative cooling systems, such as cooling towers, is recommended as warm weather arrives and these systems begin working at full capacity. Now is the time to review your cooling tower user manual and inspect all components.

Stephen Andrew

It’s important to consult with your safety officer and follow all safety protocols before beginning the inspection process. Always shut off electrical power to the cooling tower fan motor using lockout/tag out procedures before proceeding. A thorough cooling tower inspection involves using a methodical process to review and document the condition of multiple components and systems.

The checklist, below, is based on our experience and comprises recommendations in several important areas:

Tower casing

• Inspect the exterior of the tower for leaks and cracks. We recommend walking around the tower twice.
• First, be aware of trip hazards as you focus on the lower portion of the tower.
• The second time around, look higher for cracks and leaks, signs of vibration and loose hardware, and the presence of rust or biological fouling, which could indicate a damaged water distribution system.

Louvres, heat transfer fill and drift eliminators

• Check louvres for deterioration and excess scale build-up.
• Inspect the fill media for excess scale, algae and other contaminants. Some light scale is typical on fill and can be removed with brushing in a crossflow application. Inspection of counterflow fill can be performed using an endoscopic camera. If the fill is heavily scaled or damaged, tower performance will be adversely affected.
• Drift eliminators should be clean and free of debris. Ensure the seals are in place and in good condition

Cold water basin

• It is vital that your cold water basin and anti-vortex screens are properly placed and free of debris. • If your cold water basin includes equipment such as basin sweepers that go to side filtration, check nozzle placement to ensure proper water flow.
• Inspect water level probes, whether manual or electronic, for corrosion.
• When the basin is clean and components are operational, refill the cold water basin to the recommended operating level.

Hot water basin (if applicable)

Remove the basin covers to clean the water distribution system basin and nozzles.

Then, properly secure the covers.

Water distribution pipework

Check that all pipes are positioned correctly and that they are secure.

Check that all the nozzles or spray arms are installed correctly.

(Tip relating to counterflow application: Removal of an air inlet panel at low level during operation can allow you visibility of the flow from the underside of the fill pack. Any areas of noticeable heavy flow may be the result of a dislodged lateral pipe or missing nozzle.)

(Tip relating to crossflow application: Noticeable dry spots on the fill media may be the result of a blocked nozzle in the hot water basin.

Piping

Check all supply and return piping to and from the tower; confirm valves are open and that the water treatment system is operating properly.

Fan

• Check the fan; blades must turn freely with equal tip clearance between the blade and the shroud. • Verify blade pitch to eliminate vibration. Ensure the blade angle is consistent across all blades.
• Check that the fan drain holes are clear.

Motor

• Turn the motor manually and confirm hardware is tight and free of corrosion.
• Moisture and heat are detrimental to motors. Check that open drain holes match motor orientation.

Belt drive

• Check tension and wear on your belt drive.
• Inspect pulleys for corrosion and loss of metal in the grooves.

Gear drive

• Check oil level.
• Check oil appearance for cloudiness or particulates, signs of water and other contamination.
• Check and lubricate bearings.
• Check seals for signs of leakage.

Driveshaft

• Check alignment of driveshafts and couplings.
• Inspect for corrosion and damage.
• Check rubber components for cracks and brittleness.

This article provides an overview of the various considerations necessary to safely and thoroughly inspect an HVAC evaporative cooling system. It is important that you always consult the cooling tower user manual and follow the manufacturer’s recommended practices. As additional resources, I recommend following industry water management best practices as outlined in Health and Safety Executive’s HSG274 Part 1: https://www.hse.gov.uk/pubns/priced/hsg274part1.pdf

Stephen Andrew is Parts & Service Manager (EMEAI), SPX Cooling Technologies. He may be contacted at Stephen.Andrew@spx.com.