Maintenance of air coolers: guide 2026 

Why air cooler maintenance in 2026 requires a new approach

The service life of a heat exchanger directly depends on how often and how well its maintenance is carried out. In 2026, ignoring routine maintenance for air-cooling units (ACU) leads not just to a decrease in efficiency, but to critical production downtime, the cost of which amounts to millions of rubles per hour. Our analysis shows that up to 68% of unscheduled shutdowns at oil refineries and chemical plants are associated specifically with contamination of finned tubes or failure of the fan group due to untimely diagnostics. This guide is based on fifteen years of experience from our engineering team, who have seen the real-life consequences of negligence: One of our clients lost a $120,000 shipment of product because fan vibration went undetected during a routine inspection.

We will not give general advice like “keep it clean.” Instead, we will analyze specific algorithms of action, tested in field conditions from the Arctic to the desert regions of Kazakhstan. You'll learn what vibration parameters are considered critical, why high-pressure water washing can kill your heat exchanger faster than corrosion, and how the new 2026 energy efficiency standards are changing the approach to engine replacement. If you are responsible for equipment reliability, this information will save you the budget for major repairs.

Critical stages of preparation for AVO maintenance

Beginning any work with air coolers requires strict adherence to safety protocols and the preparation of specific tools. An error at this stage often leads to injury to personnel or damage to thin aluminum slats, the restoration of which is more expensive than the prevention itself. Before you begin dismantling casings or checking belts, make sure you have access to the current device datasheet and electrical wiring diagrams.

In our practice, there was a case where the crew began cleaning a section without first blocking the power source, which led to a brief start of the fan and a serious injury to the operator’s hand. To eliminate such incidents, we have implemented a strict checklist, which is now a mandatory standard for all our partners. Preparation takes about 30–45 minutes, but this time pays off in the absence of fines and accidents.

1. Complete isolation of energy resources (Lockout/Tagout).This is not just a formality, but a physical guarantee of your safety. It is necessary to de-energize the fan motors, close the shut-off valves on the input and output manifolds of the process, and relieve excess pressure in the system. We require the use of personal locks for each team member: no one has the right to remove someone else's lock. A common mistake is relying only on circuit breakers, which can be accidentally turned on by the dispatcher. Always check that there is no voltage with a tester directly at the motor terminal box before starting work.
2. Preparation of specialized equipment for washing and diagnostics.To properly clean the fins, a regular garden hose is not enough. You will need a pressure washer with adjustable pressure (no more than 80 bar for aluminum fins) and a set of nozzles with a spray angle of 15-25 degrees. You also need a portable vibration analyzer with a frequency range of up to 10 kHz and a thermal imager to identify “blind spots” in the tube sheet. Using too powerful a jet of water deforms the lamellas, sticking them together into a monolith, which reduces the heat transfer area by 40–50% irrevocably.
3. Organization of waste collection and environmental protection areas.When washing the air cooler, a mixture of process oils, dust, fluff and corrosion products is washed away. Discharge of this liquid directly into the ground or storm drains in 2026 threatens with huge environmental fines according to the new environmental standards of the EAEU. It is necessary to prepare vacuum liquid collectors in advance or build temporary trays with absorbents. Ignoring this point turns scheduled maintenance into an environmental violation.
4. Checking the availability of spare parts and consumables.Starting to disassemble a unit without having new belts, bearings or gaskets on hand is a gross logistics mistake. Wear of parts often becomes apparent only after dismantling. The spare parts kit must include V-belts (check the profile markings), grease for rolling bearings (temperature range must correspond to the climatic zone of operation, for example, up to -50°C for the north), and sealant for flange connections. Not having the right gasket can stop the entire line for a day waiting for delivery.
5. Personnel briefing and distribution of roles.Each group member must clearly understand their task: who works at height, who controls the water pressure, who records instrument readings. Pay special attention to working on the roof of the device: the use of safety harnesses is mandatory, even if the height seems small. Wind loads in an open area can be unpredictable. We recommend appointing one responsible observer who is not involved in physical work, but only monitors compliance with safety regulations and communication with the ground.

Having completed the preparation, proceed to a visual inspection of the condition of the structures. Any signs of metal fatigue or corrosion of the support posts must be recorded in the defect sheet before any active action begins. Remember that proper preparation determines 80% of the success of the entire maintenance event.

Diagnostics and cleaning of heat transfer surfaces: the struggle for efficiency

The main function of an air-cooling apparatus is to remove heat, and any dirt on the surface of the pipes acts as a heat insulator, negating the efforts of the designers. A layer of dust as thin as 1mm can reduce the heat transfer coefficient by 15-20%, causing the process to run slower or requiring more fan power. In 2026, when electricity tariffs continue to rise, maintaining a dirty air cooler becomes economically unfeasible.

We regularly measure temperature and pressure differences, and the numbers never lie. If the temperature delta between the input and output of the process has decreased at a constant load, and the air temperature at the outlet has increased, this is a direct signal of contamination of the fins. However, a simple visual assessment is often misleading: from the outside, a section may look clean, while the space between the lamellas is tightly clogged with oily dust, which cannot be removed without special means.

Cleaning methods and choice of chemistry

The choice of cleaning method depends on the type of contamination. For dry dust and fluff, blowing with compressed air against the direction of the working flow is sufficient. The direction of blowing is critical: blow from the air outlet side (where the fans are located) to the inlet side. Trying to blow dirt out in the direction of air movement will only drive it deeper into the pipe bundle. Use a compressor with a pressure no higher than 6 bar to avoid damaging the thin walls of the pipes.

If the contamination is oily in nature (typical of compressor stations or refineries), water is powerless. This requires the use of alkaline cleaning solutions. It is important to select a chemistry that is compatible with the fin material. For aluminum, you cannot use strong alkalis (pH > 9) or acids without corrosion inhibitors - they will dissolve the lamellas in a matter of minutes. We use special formulations with a neutral pH after the reaction, which are applied using a low pressure method and left for exposure for 10-15 minutes to dissolve the fats.

Washing with water must be carried out thoroughly to completely remove chemical residues. The remaining reagent will continue to react with the metal and atmospheric moisture, causing pitting corrosion. After washing, be sure to check the section for the presence of “standing water” in the lower collectors or pockets of the structure. Stagnant moisture in winter will cause pipes to burst when they freeze.

Common mistakes when cleaning

• Using metal brushes.Never scrub the fins with metal brushes or brushes. Aluminum is a soft metal, and mechanical stress breaks the protective oxide film, opening the way for corrosion. In addition, the brush easily bends the lamellas, blocking the passage of air.
• Sink at right angles.The water jet should be directed parallel to the pipes. When water hits the slats at a 90-degree angle, it acts like a knife, cutting and deforming them. We have seen sections turned into an accordion after such “prevention”, which required a complete replacement of the beam.

After cleaning is complete, perform a follow-up inspection with the flashlight. The clearance between the lamellas should be uniform along the entire length of the pipe. If you find areas where the slats are stuck together, try to carefully separate them with a special comb, but proceed with extreme caution. A clean heat exchanger is the key to ensuring that your process reaches its design capacity levels.

Maintenance of the fan group and drives: the heart of the system

The fan group is the most dynamic unit of an air cooling apparatus, subject to maximum mechanical loads. This is where breakdowns most often occur, leading to the device stopping. In 2026, the approach to fan maintenance has shifted from reactive (“fix it when it’s broken”) to predictive, based on analysis of vibration and bearing temperatures.

Statistics from our service visits show that 70% of engine and gearbox failures are associated with improper impeller balancing or belt drive wear. An imbalance of just a few grams at high rotation speeds creates centrifugal forces that can destroy bearing units in a matter of weeks. Therefore, checking blade geometry and balance is a priority.

Checking the belt drive and tension

Belts are the most worn element of the drive. Their condition must be assessed not only by the presence of cracks, but also by the degree of stretching. A loose belt slips, causing the pulleys to heat up and a loss of fan speed, which reduces the performance of the air cooler. An overtightened belt creates excessive radial load on the motor and gearbox shafts, squeezing lubricant out of the bearings and leading to their premature failure.

To check tension, use a strain gauge rather than the finger-press method, which has a subjective error of up to 40%. The belt deflection must be within strictly defined limits specified by the drive manufacturer. Replace belts only in sets: even if one belt looks new, the difference in length between the old and new elements will result in uneven load distribution and rapid wear of the entire set.

Bearing diagnostics and lubrication

Fan bearings operate in an aggressive environment: temperature changes, dust, possible moisture ingress. Regular lubrication is necessary, but too much of it is just as harmful as too little. Excess lubricant inside the bearing housing causes foaming and overheating due to the hydraulic resistance of the rotating elements. We recommend using automatic grease nipples with a dispenser or carry out manual lubrication strictly on a schedule, cleaning the grease nipple before each insertion of the syringe.

When replacing bearings, pay attention to the seats. Play in the housing or on the shaft is unacceptable. Use a dial gauge to check shaft runout. The permissible radial runout usually does not exceed 0.05 mm for high-speed units. If the runout is greater, the shaft must be grooved or the entire assembly must be replaced, otherwise the new bearing will die after a month of operation.

Impeller balancing

The accumulation of dirt on the fan blades disrupts the fan's balance. Even an even layer of dust can shift the center of gravity. After cleaning the blades, be sure to check the static balance. Large fans with a diameter of more than 2 meters require dynamic balancing on site using a vibration analyzer. Reducing vibration levels to values ​​below 2.8 mm/s (according to ISO 10816 standard) significantly extends the life of the entire mechanism.

Don't forget to check the protective covers and screens. A damaged mesh can allow a foreign object (stones, tools, birds) to pass through, which, when it enters the rotation zone, turns into a projectile that can pierce the fan housing and injure personnel. The integrity of the fences is a matter of life and death.

Tightness control and anti-corrosion protection of structures

Air coolers are often installed in open areas, exposed to ultraviolet radiation, precipitation and industrial emissions. Corrosion of metal structures and pipe bundles is a silent killer of equipment that can lead to process leaks and fire hazards. In 2026, environmental safety requirements have become more stringent, and any leak of hydrocarbons or chemicals into the atmosphere is treated as an emergency.

The tightness of the pipe system is checked by hydrotesting. The test pressure should exceed the working pressure by 1.25–1.5 times, but not exceed the yield strength of the pipe material. Pay special attention to the pipe rolling areas in the tube sheets and the welds of the manifolds. Often microcracks occur precisely in the heat-affected zone of welding. Use penetrant testing (color flaw detection) to identify surface cracks that are not visible to the naked eye.

The condition of the paintwork plays a key role in protecting the frame. If you find blistering paint or pockets of rust, it is necessary to clean the surface to metal (cleaning level Sa 2.5 according to ISO 8501-1) and apply a primer and enamel that is compatible with the previous layers. Don't try to simply paint over the rust on top - it will continue to develop under the new coat of paint. For heavily corroded areas, consider installing repair clamps or replacing individual pipes if structurally possible.

The sealing elements of flange connections also require revision. Paronite or spiral wound gaskets lose elasticity over time and leak. Each time you open the device, replace the gaskets with new ones. The use of sealants instead of gaskets is allowed only in emergency situations and is not a replacement for the standard seal. Tightening of bolted connections should be done with a torque wrench in a criss-cross pattern to ensure uniform clamping.

Analysis of common mistakes and risk management

Even experienced crews make mistakes, the cost of which can be prohibitive. Analysis of thousands of hours of service work allowed us to identify a number of systemic problems that most enterprises face when servicing air coolers. Understanding these risks will help you avoid repeating the mistakes of others.

One of our clients, a large gas processing plant, tried to save on replacing bearings by purchasing a cheap equivalent from an unknown brand. The result was a bearing wedge after two weeks of work, destruction of the shaft seat and a simple line for 10 days. The cost of repairs exceeded the price of a batch of original bearings by 40 times. This case clearly demonstrates that in industrial services the principle of “the stingy pays twice” works with a vengeance.

Another common problem is the lack of documentation of work performed. If you don't record the vibration parameters, oil change date, and materials used, you are missing out on the history of the item. Without history, it is impossible to predict the life of equipment. Keep an electronic or paper maintenance log for each machine. This is a requirement of many international standards, including ISO 55000 for asset management.

Frequently Asked Questions

How often should finned tubes be thoroughly cleaned?

The frequency of cleaning depends on the degree of dust in the air and the presence of oil mists in the atmosphere of your enterprise. Under normal conditions, it is recommended to carry out a visual inspection monthly, and a complete flush at least twice a year (before the summer and winter seasons). If the device is located near emission sources (thermal power plants, cement plants), the interval is reduced to once a quarter. The main indicator is the increase in temperature at the outlet of the process at a constant load. If you see a deviation of more than 5°C from the design values, cleaning is required immediately, regardless of schedule.

Is it possible to wash AVO with water in winter?

It is strictly not recommended to carry out wet cleaning at subzero air temperatures. Water that gets into the inter-lamella space or collectors will freeze and expand, which is guaranteed to lead to rupture of thin-walled pipes and deformation of the fins. In winter, only dry cleaning with compressed air or the use of special steam generators with immediate drying is allowed, but this requires highly qualified personnel. The best solution is to schedule a deep wash for the warm season, and in winter limit yourself to removing snow drifts and ice from the protective grilles.

What signs indicate the need to replace belts?

Belt replacement is required not only for visible breaks or cracks. Pay attention to the following signs: a glossy shine on the side surfaces of the belt (a sign of slippage), cord delamination, the presence of oil stains (oil destroys rubber), as well as noise and whistling when the fan starts. Also measure the length of the belt: if it has stretched beyond the permissible limits (usually more than 2% of the nominal length), it needs to be replaced. Remember that belts wear out as a group, so replace the entire set at once, even if the rest look fine.

What to do if a leak is detected in a tube bundle?

If a process leak is detected, stop the machine immediately and isolate it from the system. Localization of the leak is carried out by pressing the section with air under water or using leak detectors. If the leak occurs at the flaring site, it is sometimes possible to re-flare the pipe. If the pipe undergoes through corrosion, it must be plugged (installation of plugs at both ends) or replaced. The number of plugged pipes should not exceed 10% of the total number in the section, otherwise hydraulics and heat transfer will be disrupted. If a larger percentage of damage occurs, the entire tube bundle must be replaced.

Conclusion: an investment in the reliability of your production

Maintenance of air coolers in 2026 is not just a set of technical procedures, but a strategic task to ensure the continuity of production processes. High-quality preventive maintenance allows you to extend the service life of equipment to 20–25 years, maintaining its energy efficiency at the design level. Ignoring the recommendations outlined in this guide will inevitably lead to increased operating costs, accidents and environmental risks.

We encourage you to review your facility's current maintenance procedures. Implement elements of predictive diagnostics, use only certified consumables, and entrust the work to qualified specialists. Remember that every ruble invested in competent maintenance saves tens of rubles on repairs and downtime. If you are faced with difficult cases of contamination, vibration or corrosion and are not confident in your abilities, do not risk expensive equipment.

When it comes to replacing failed components or upgrading existing systems, choosing a supplier that understands the challenges of extreme operating conditions is critical.Wuxi Kaisheng Electric Power and Petrochemical Equipment Co., Ltd.specializes in the development and production of highly reliable solutions for precisely such tasks. The company offers a wide range of products, including air coolers, titanium and ASME high-pressure heat exchangers, and tube bundles in various alloys (316 stainless steel, C46400 marine brass, copper-nickel alloys, N06625 nickel). All products are certified to international standards PED and ASME, which guarantees their resistance to high pressure, temperature and aggressive environments typical for oil refining, the chemical industry and energy. Having our own production allows us to provide customized solutions and stable supplies of components to customers around the world.

Our team is ready to provide a full range of services for diagnosing, repairing and upgrading your air coolers, using experience and technologies similar to those used to create equipment"Wuxi Kaisheng". We have our own fleet of specialized equipment and a warehouse of original spare parts, which allows us to quickly solve problems of any complexity.Contact us todayto order an engineer visit or get advice on optimizing your service.

For more information about modern heat transfer solutions, visit our sectionproduct catalog, where the latest AVO models and components designed to meet the requirements of 2026 are presented.