Category Archives: Chillers

An HVAC chiller is often the most costly piece of equipment in a building and the most expensive to tun. While chillers often last many years, eventually you will have to ask yourself, when is the best time to repair or replace the chiller, Read on and learn more about what is the best answer.

Chiller Replacement Considerations

Take into account the following when you are thinking of replacing the HVAC chiller:

• It can take a long time to install a chiller often in excess of 12 months when you take into account the time it takes to make the replacement decision to the time the chiller is fully installed and operational.
• The occupants of the entire building can be disrupted as modifications may be required to the piping system and ceilings and walls may have to be opened, closed or even removed for the work to progress.
• Uninterrupted cooling may be a critical need for the building, so an arrangement will have to be made for temporary systems of chilling.

Chiller Maintenance Considerations

The problems above are often enough to make people seek out maintenance options. But you have to be careful as it may be a false economy in the long run so consider the following:

• In the past twenty years advances in technology mean the operating efficiencies of chiller have improved greatly, helping to balance the cost of a brand new chiller. In short, a new chiller operating on a full load may only need around 60% of the energy taken by a twenty-year-old chiller.
• Over time the operations of the building may have changed as well as structural improvements like new roofing and energy efficient windows installed. These all have an impact on the cooling load of the building. if the load has increased, the chiller may be an inadequate size and vise-versa. either way, the efficiency of the chiller is being compromised.

Existing Chiller Maintenance And Reliability

As components wear over time, chiller outages are likely to become more frequent. It is important to maintain an accurate chiller log so vital information regarding the performance of the chiller can be retained and used for future reference purposes. When looking at the current and future requirements and maintenance costs of the existing chiller, remember parts for older chillers are becoming scarce an harder to find. On occasion the decision to replace the chiller is obvious. If your chiller is in excess of twenty years old, works over 1000 hours per year and services loads that are critical, a replacement may be a good idea. But maintenance may be better, if, for example, your 10-year-old chiller is well suited to its requirements and had been properly maintained.

Phoenix Chiller Maintenance & Repair

If you have a industrial or commercial building that uses chillers All Kote Lining, Inc. can help maintain and repair your chiller.  Regular chiller maintenance, chiller tube coating, and other quality services help chillers be more efficient, use less energy, and ultimately last longer. Give us a call to find out what we can do for you and your chillers in the Phoenix Valley.

Call Today – 480-966-4446

This chiller maintenance checklist will help you ensure you catch all of the important areas of your chiller system.  In this post we’ve provided an air cooled chiller maintenance checklist as it is the most common design.

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Maintenance Checklist – Maintenance Tips – Schedule Maintenance

Chillers are a critical element in HVAC systems.  Chillers take the heat out of the air and also are implemented in industrial settings to cool down equipment. This checklist is designed to help chiller owners and maintenance personnel conduct detailed and reliable maintenance on air-cooled chillers.

Download & View our Chiller Maintenance Checklist PDF

Air Cooled Chiller Maintenance Checklist

Follow this list as you inspect and maintain your chiller.  Each item is important and diligent chiller maintenance will save money and make the system last longer.

1. Inspect water inlet and outlet for leaks
2. Clean out and inspect the sump for corrosion
3. Cooling coils need to be inspected and surfaces cleaned. Check for leaks, corrosion, or bent fins
4. The zone control actuators should be inspected, cleaned, and all adjustments made
5. The compressor needs various areas checked, these include: refrigerant charge, vibration, crankcase heater, oil levels and changes, operating temperatures, and if there are any leaks of refrigerant or oil.
6. Condenser fans should be cleaned, bearings need to be checked for wear and lubricated, and belts and couplings need to be checked and tightness checked or adjusted as necessary.
7. The condenser coil should be check for corrosion and leaks and all finds or combs need to be checked for bent sections.
8. The electrical disconnect should be inspected for proper operation and the contacts should be inspected and cleaned.
9. The exhaust air damper needs to be inspected for proper operation, have the bearings lubricated, and calibrate or adjust it for optimal operation.
10. Return air dampers also should be checked for proper operation, calibration, and bearings be lubricated.
11. The fresh air damper should also be inspected, calibrated, and bearings lubricated.
12. The filter dryer also should be inspected and any old, dirty, or damaged filters be replaced.

Chiller Maintenance Tips

The simple fact is that the chiller makes up for a significant portion of your electricity usage, even at peak performance.  If you’ve got maintenance issues it can easily use an extra 10%, which hurts the bottom line.  While technology has improved to remotely monitor chillers and technology has produced more durable and efficient parts, maintenance is still key.

Maintain A Log Daily

Knowledge is power and saving power is a big deal when it comes to chillers.  Recording operating conditions such as flow rates, pressures, fluid levels, and temperatures helps build a useful record of your system.  While it was standard to do bi-monthly checks today’s continuous monitoring technology allows you to keep accurate daily logs that will help you narrow down maintenance issues before there’s a bigger problem.

Condition Your Water

Corrosion and scaling are always a challenge in air cooled chiller systems.  Treating the water in your system helps cut down on corrosion, scaling, and the growth of biological contaminants such as Legionella.  All of these issues can let to a decrease in heat transfer caused by fouling and diminished heat transfer due to build up inside of pipes.  It’s important to continually monitor your chilled water loops remotely and visually inspect them annually.

Clean Heat Transfer Tubes

A big part of the efficient operation of chillers relies on clean heat transfer tubes.  If your system has mud, minerals, algae, or scaling it will coat the inside of the tubes and insulate them.  While insulation is great at keeping heat out of a home in the summer the heat transfer in chillers is the cornerstone of how the system functions.  Neglecting your chiller tube cleaning will end up inflating your operating costs and likely result in additional maintenance and more frequent downtime.

Maintain Refrigerant Charge

Your chiller’s ability to cool relies on having the right amount of refrigerant. To ensure your systems optimal efficient performance make sure you’ve got the right level of refrigerant.  If there is air, moisture, or leaks in your system it will impact it’s performance.  With insufficient refrigerant it will take more electricity for your system to perform the same cooling effect.

Provide Cooler Water

Providing cooler water for the condense improves the chiller’s performance.  It will not have to work as hard to condense the water and will run more efficiently.  In some cases this technique can compensate for problems with coils.  While this does fix the problem it is a temporary solution as the chiller must work harder for the same effect.

Purge Non-Condensables

Chillers function on the principle of condensing refrigerant to cool.  If moisture or air leaks into the system it introduces non-condensable elements into the system that rob it of efficiency.  The percentage can be as high as 7% below the rated performance of the chiller system you have.  When considering how much energy a chiller uses to begin with and extra 7% adds up quickly.

Maintain Appropriate Flow Rate

The rate at which your chilled water flows through the chiller does impact the chiller’s performance.  If it is too slow it lowers efficiency. Too fast and it will cause erosion, vibration, and noise.  It is best to keep the flow rate of your chiller somewhere between three and twelve feet per second. The exact speed will depend on your chiller’s design and the load needed by your location.

Upgrade To Variable Speed Drives

In most cases the chiller motor is the largest draw on electricity in the entire building.  Single speed drives are on or off and cannot adjust for the difference in load the system is running under.  In contrast a variable speed drive saves energy as it can adjust the speed to match the load.  This saves a significant amount of energy in your chiller system. In addition variable speed allows the system to ramp up more smoothly in the case it is turned on in an emergency situation.

Check Oil In Compressor

If your compressor uses oil make sure you send a sample of it for inspection at a laboratory once per year.  Due to the hermetically sealed nature of a close refrigerant system the compressor oil should only be changed if the lab deems it necessary.  If there’s excessive moisture it can point to there being a problem with purging the system effectively.  If the oil is changed ensure the filters are tested and replaced when there are pressure drops. In the case your system uses magnetic bearings and is frictionless your system will not have compressor oil.

Inspect Motors & Starters

You can save energy and downtime if you inspect your motors and starters.  To do so inspect the sensor calibration and safety on the microprocessor controls.  Also take the time to inspect the wiring and connections in your chiller system at common wear points and hot spots. Pay attention to signs of refrigerant leaks and test motors for insulation faults.

When To Inspect Chillers

Chillers should be inspected and maintained at least 2 times a year in areas where they are only used during the cooling seasons, or 4 times a year in areas that cool in all 4 seasons. Quarterly inspection helps your chillers, HVAC system, and cooling towers last longer and run more efficiently.

Maintained Chillers Operate More Efficiently

Using this checklist you can get better performance out of your chiller and cooling system. The better maintained your chiller is the less energy it uses, and that saves you money on utilities.  As the chiller and HVAC system is one of the largest draws of electricity in many commercial, industrial, and medical facilities it is important to inspect, maintain, and repair chillers.  Regular inspection and chiller maintenance will help save money and make the system last longer.

Chiller Maintenance in Arizona

If you have a property such as a commercial building, medical facility, or industrial site that uses chillers for processes or HVAC All Kote Lining, Inc can help you take care of the chiller maintenance you need to keep your energy use down and make your equipment last longer.  We inspect, maintain, repair, and line chillers with the most durable coatings available. Give us a call today to find out what we can do for your company at 480-966-4446.

Industrial chillers are used in large commercial or industrial buildings. They are much more efficient at cooling these large spaces and work by using a de-humidification or vapor compression technology. How a chiller works is fairly complicated but we will examine is a bit more closely in this post.

How Industrial Chillers Keep It Cool

Vapor back to liquid

When operating correctly the condenser has a twofold role in the industrial chiller. The first step in a chiller is taking superheated vapor and reducing it back to liquid coolant. This process mush transfer enough head from the refrigerant to lower its temperature to convert it back into a liquid form. Once this is done the condensation may begin. The quality of the refrigerant continues to improve as the heat is transferred out of the water, or refrigerant. This process continues until the air has been completely transferred back into liquid. In a perfect world this process is complete by the time the coolant reaches the outlet of the condenser. However to prevent pressure losses and liquid flashing subcooling helps prevent issues with introducing vapor back into the system.

Cooling the hot liquid refrigerant

Even after the condensation process the refrigerant is still at a high temperature and needs to be cooled before it can be reused as a heat transfer medium. In chillers this is done by decreasing the pressure. Physics dictate that if the pressure is reduced in a space that the temperature will follow. So you can count on the temperature to follow if you reduce the pressure.

Temperature Reduction Through Lowering Pressure

To do this in the chiller restriction is a necessary part of reducing the pressure. System loads vary based on a few different elements so the system cannot regulate this depressurization process. The thermostatic expansion valve is responsible for lowering the pressure in the tanks holding the refrigerant that needs to be cooled. This is an adjustable pressure regulator that can adjust for the load of the chiller. The thermostatic expansion valve will not maintain the constant vapor pressure and is only a superheat controller. It simply provides the reduction in pressure necessary to a designated level which is determined by size load, system conditions, load demand, the compressor size, and the thermostatic expansion valve. Some systems require constant evaporator temperature. In these cases a pressure regulating valve should be added to the system. This will help maintain the pressure corresponding the saturation level.

Pressure Regulation

Pressure loss in the thermostatic value can be explained by the mixture of both states of refrigerant. Meaning that when both the liquid and vapor exist in a section of the cooling system superheating or subcooling cannot be achieved. The saturation temperature will always be directly linked to the pressure.

To remove the necessary heat some of the liquid refrigerant must be boiled. This is another process that results in lower liquid temperatures. When the chiller is working properly and subcooling is achieved the difference between the cooled refrigerant introduced into the system will increase the efficiency due to the energy decreased by the boiling of the refrigerant.

Complete Vaporization

The evaporator tubing is the final leg of the refrigerants journey through the cooling system. At this point it is a mixture of both vapor and liquid. Heat is applied to the tubing by having warm air blown over it. This process boils off the last of the liquid leaving only vapor. The last molecule of liquid should be converted to vapor at the evaporator outlet. This means that the vapor at the inlet of the compressor is sufficiently saturated.

This process continues until the space that needs cooling is at the desired temperature. Then the equipment cycles off and waits for a need for it to come back on.

Chiller Maintenance & Repair Phoenix AZ

If you have a commercial property that uses a chiller to keep the building cool you need to make sure that you are getting regular maintenance. This will help prevent repairs and promote better energy efficiency. If there are already problems we repair chillers and can provide coatings to help prevent corrosion of chiller tubes. Give us a call and find out what we can do for your chiller in the Phoenix areas. Call today at 480-966-4446.

Taking things for granted is part of human nature. We rarely consider the way everything works and stays working each day when we go about our routines. The ignition fires up our cars, the coffee pot brews up some motivation every morning and we rarely give the things that make our lives comfortable much thought until they aren’t working. This is no different than HVAC systems. A big part of the HVAC system is the chiller, and the tubes that make it work. Understanding chiller tube cleaning helps us keep our chillers working and our buildings cool during the warmer weather in Arizona.

To keep chillers and HVAC systems efficient they need to have regular maintenance and coatings. It is no small task to care for these critical components of the cooling system for large commercial spaces. Coatings help prevent buildup and cleanings kick out deposits that reduce thermal transfer.

Large commercial spaces use a lot of energy and the chiller can be one of the largest consumer of energy. As the price of energy increases, the savings of regular cleaning and chiller coatings increases. Keeping daily logs, making preventative maintenance a priority, and scheduling regular chiller maintenance will keep your overhead costs down.

Key Chiller Tube Cleaning Considerations

Tube Cleaning

The efficiency of the chiller tubes is completely dependent upon heat transfer. Thermal efficiency is limited by buildup on the inside of the chiller tubes. Most large chillers are comprised of literally miles of tubing which helps achieve the heat transfer in the evaporator and condenser. Keeping the tubing clean therefore is the way these critical HVAC components do their job and use less energy. The best way to keep tubes clean is to have planned outages for cleaning, keeping up with water treatment, and having chiller tube coatings which help control buildup.

The efficiency of chillers drop steeply as buildup develops inside the chiller. It is deposited by contaminants in your water that is recycling through your system and by contaminants being brought in from the air cycling through your cooling tower. The contaminants found in your chiller can range from algae, mud, sand and even minerals that develop into scales that all sap the heat transfer.

The percentages of decreased thermal transfer drop quickly even with what seems like thin layers of contaminants. Even a coating as thin as .0045 can drop chiller tube efficiency by as much as 44%.

Water Treatments

Water used in cooling towers and chillers usually comes from local water supplies. This means there can be additives, sand, minerals, and other elements that cause fouling and deposits in chiller tubes. Even the atmospheric conditions around the cooling tower have a significant effect on the quality and contents of the water used in HVAC systems.

This means that there needs to be water treatment in the system to help fight biological growth, scaling, and other deposits. The most contaminated the water the greater need for water treatment and a more frequent and robust water treatment plan.

Chiller Motors & Electrical Components

The chiller motor in your HVAC system is potentially the greatest user of electricity in your entire building. We might obsess about shutting off lights in our homes and offices, but the chiller is responsible for using an enormous amount of electricity to keep our commercial properties cool and comfortable.

Chiller motor maintenance is a critical part of keeping your system efficient and your energy bills as low as possible. The shaft seals, and air vents should be checked and kept clean.  All of the insulation, wiring, and connections should be maintained to keep the system running properly and avoid unscheduled downtime.

Methods Of Tube Cleaning

For the best thermal performance it is clear that regular cleaning and maintenance of the chiller tubes is not optional. It is mission critical and should be carried out on a regular schedule by properly trained and equipped chiller maintenance technicians. There are different methods that these technicians use to get your tubes clean and maintain the thermal efficiency of your chillers.

Chemical Cleaning

One of the older methods of tube cleaning, is has seen a decrease in use in the last decade. Acid solutions are used in chemical cleaning that soften and break down the scale and deposits in the tubes. The acidic solutions are circulated through the tube bundles and help remove the layers of energy robbing debris.

Chemical cleaning does have the advantages of breaking down mineral scale so brushes can effectively remove them, and it can take tubes back to bare metal. It has lost some of its former popularity because it is time consuming, the chemicals are costly, requires increased training, and the chemicals are dangerous and difficult to dispose of.

Rod & Brush Cleaning

The rod & brush method is very similar to the cleaning of a gun barrel. It is probably the oldest type of chiller cleaning. A rod of metal is tipped with a wire or nylon brush that is larger than the tube. The process generally involves flushing the tubes with water, and then forcing the rod and brush through the tubes. After the rod has been pushed through water is sprayed again to remove any debris.

This is a popular method because it is inexpensive, but it does have some disadvantages. It is labor and time intensive. The chiller might be in an area that prevents the longer rods being used. Smaller sections might have to be assembled as the brush is inserted into the tube, adding to the time of the job. Also the bristles on the brush tend to fold down and end up swabbing instead of brushing. Another limitation of this process can be if the tubes brushed first dry and the debris reattaches before the final rinse is completed.

Rotary Tube Cleaners

Using either an air or electric motor these chiller tube cleaning machines include a cleaning tool that uses water and circular motion to help remove debris. A flexible shaft is set inside a plastic casing which directs water directly to the cleaning head. The tools used with these machines include scrapers, hones, brushes, and buffing tools. This combination of tools is what makes the rotary tube cleaners some of the best at removing deposits, including hard scale. The job is done by one operator feeding the shaft through each of the tubes. Best of all it only takes one pass for each tube.

This is one of the most used, and popular chiller tube cleaning types. It is due to the fact that is it one of the most effective cleaning methods paired with the low cost. The process takes little time and uses less consumables that other cleaning methods. It also only requires one technician, only opening one side of the chiller, and is the best type of cleaning for internally enhanced chiller tubes.

Tube Cleaning Guns

As the name suggests this method of tube cleaning features a gun that uses air or water to shoot a projectile through the tubes. These projectiles vary from metal or plastic scrapes to brushes and even rubber bullets.

This is a popular type of cleaning for light deposits and is very fast. With the right conditions tubes can be cleaned quickly, even in a matter of seconds per tube. It does have the limitation when it comes to the type of deposits it can remove. Harder scaling or stubborn deposits are more difficult or impossible to remove with this method. It also requires the opening of the chiller on both ends to allow the transfer of air as the projectile goes through the tube.

The equipment can be costly to buy and maintain along with some units being somewhat dangerous to operate. The pressure released into the tube might not make it through and be rejected at the operator when the gun is removed. Some units include pressure relief valves that prevent this danger to operators.

On Line Cleaning Systems

Cleaning systems are available for use while the system is active. This means that they help reduce the frequency of downtime. There are two on line tube cleaning types available today. One uses foam balls that circulate through the tubes in the chiller and the other includes the use of plastic brushes that are installed into each of the tubes. The idea behind the foam balls is that they should work through each and every tube in the bundle often enough that they will clean the tubes from becoming dirty. The plastic brush system features plastic baskets which are permanently attached to both sides of the chiller. Periodically the direction of the flow of water is reversed to cause the baskets and brushes to travel the length of each tube, removing debris.

With proper water treatment these systems can reduce or even eliminate the needs for tube cleaning. However these systems are costly to purchase and install. They also are not suitable for chillers that use hard water that promotes hard scaling.

Internally Enhanced Tubes

The only cleaning method for this type of chiller tube is rotary tube cleaning. These chiller tubes are making advancements with thermal efficiency and are becoming more and more common. Internally enhanced chiller tubes are those that include rifling on the inside. Rifling is when spiral groves run the length of a tube. They cause the water to circulate more evenly and provide increased surface area. Both of these elements increase the chiller’s thermal efficiency.

The rifling does mean there are areas that are below the surface of the metal. This means that many cleaning methods are simply not suited for getting into these crevices that increase efficiency. The best type of rotary tube cleaners to use in these applications are bi-directional units. This means that on the way in, and the way out, the brushes can be moving in the same direction as the spiral inside the tube. Specialized heads have also been developed to get into these grooves.

Chiller Maintenance in Arizona

If you have a chiller in or near the Phoenix valley All Kote Inc. can help you extend the life of your chiller and your cooling towers. Regular maintenance and repair keeps the system energy efficient and can save users huge amounts of energy and that means real savings on electricity bills. If you have a commercial space that uses and chiller or cooling tower make sure that you have a plan for maintenance and have All Kote help you with your chiller and cooling tower needs.