In many industries, cooling towers are placed out-of-sight, which can cause them to be neglected during common system maintenance tasks. However, with proper maintenance procedures you can keep the system working properly and hence maintain the efficiency of the entire structure.
The following are the most important tasks to include in your maintenance plans. Such tasks should be overseen by cooling tower maintenance and repair professionals, since cooling towers are mostly precariously placed, and getting to the inspection ports could be dangerous for untrained personnel.
Water is cooled by air circulating in the tower and fill, therefore poor airflow will result in uneven cooling. Airflow can be impeded by accumulation of debris within the air inlets and outlets, excessive vibration in moving parts, damaged fan blades, improper fan and motor alignment, loose mountings, improper fan pitch as well as neglect of gearbox maintenance. Fan performance degeneration can finally result in fan or motor failure, which is much more expensive to fix.
Mineral deposits from circulating water in cooling towers can accumulate over time, forming a layer of scale on the fill surfaces. Many problems result from this, including breeding of harmful Legionella and other bacteria and inefficient heat transfer between air and water. Effective water treatment can curb scale formation, but a separate descaling and chlorination schedule for should be implemented.
Water should be treated properly to destroy harmful pathogens and remove biofilms which can escalate corrosion and scale formation in the tower. It is not enough to have blowdown/bleed – the small continuous stream of recirculated water flowing into a drain where dissolved solids are eliminated – because it doesn't take care of removing biological contaminants. For this, you should implement a permanent chemical treatment procedure to remove both living and non-living micro-particles.
Closed-loop cooling towers have pumps which push water over tubes to facilitate evaporative cooling. Optimal heat transfer is only achievable if water is flowing properly. However, this can be affected by bearing failures, excessive vibration, cavitation, blocked strainers and loose connections. If unrectified, these can result in major and premature pump failures.
Sediments and algae can block nozzle sprays over time, and reduce their spraying efficiency, causing non-uniform distribution of water resulting in uneven cooling. If you find your nozzles clogging often, this could indicate that your water treatment system is inefficient, or your strainers are also clogged. You can use clog-free nozzles to reduce instances of blockages using readily available kits. Leaving clogs in place for too long can make them permanent, necessitating replacement.