Condenser Coil Failing? Here’s Why

Did you turn on your DX system only to find the condenser coil isn’t working? It may seem like a simple fix—but it often isn’t. If you can provide the unit’s model number, there’s a good chance we’ve already built a replacement. If not, you typically face two choices: wait months and pay a huge premium through the OEM, or call Capital Coil for a faster, engineered solution tailored to your system.

Condenser Coils

Condenser coils rarely freeze, so the first step is identifying the cause of failure—corrosion, age, or vibration.Condenser Coil

Old age is the easiest to address. With a few basic dimensions—coil size, number of rows, and fins per inch—we can quickly quote a duplicate. Since condenser coils are usually outdoors, they’re easy to measure and photograph. Images of headers and return bends also help us understand circuiting and sub-cooling requirements.

Corrosion often points to poor original design. Coastal or high-salt environments can degrade aluminum fins within a year or two. To prevent this, you can upgrade to copper fins with stainless steel casings for maximum durability, or opt for protective coatings—a more cost-effective solution that typically adds just 1–2 weeks to lead time.

Vibration is another common issue, especially when coils are near moving equipment. Leaks near the tube sheet—often appearing as if the tube is being sliced—are a key indicator. Proper isolation is critical, and in some cases, oversizing tube sheet holes can help reduce stress, though not all manufacturers offer this option.

Maintenance is equally important. Because condenser coils are exposed to outdoor air, they accumulate debris quickly. With tight fin spacing (12–20 fins per inch), coils can act like filters, reducing efficiency when clogged. Regular cleaning is essential, and many customers now request thicker fins to better withstand high-pressure washing and harsh cleaning agents.

When choosing an HVAC coil manufacturer, work with a partner who guides you through the engineering process. Capital Coil & Air brings over a decade of experience, ensuring a smooth process from quote to installation. Call and speak with a coil specialist today!

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Replacing Carrier Chilled Water Coils

For HVAC professionals, replacing Carrier chilled water coils is a task that demands precision. One miscalculation in dimensions, connection types, or circuit configurations can turn a straightforward replacement into a significant challenge, leading to delays and complications like compromised airflow or customer callbacks.

Why Precision Is Critical

Carrier chilled water coils are engineered with extremely precise specifications. Even the slightest deviation can result in issues such as:

  • Airflow Restrictions: A poor fit can obstruct air movement, affecting system efficiency.
  • Inefficient Heat Transfer: Suboptimal coils may lead to inadequate cooling performance and increased energy costs.
  • Connection Misalignment: Mismatched connections complicate the installation process and can lead to leaks or failures.
  • Extended Installation Times: Inaccuracies often necessitate additional rework, wasting valuable time on the job site.

It’s crucial to explain the importance of attention to detail to your clients. A so-called “replacement” coil that doesn’t meet specifications can inadvertently introduce new problems rather than solving the existing ones.

The Capital Coil Advantage

In the world of HVAC, many coil manufacturers overlook the significance of these specifications, opting for oversimplified solutions that can create headaches later on.

Here’s where Capital Coil steps in. Whether you have:chilled water coil

  • A clear model tag
  • A partial number
  • Or even just a worn-out coil

We have the expertise to provide a reliable solution. Our team has extensive experience manufacturing the coil types you depend on daily, ensuring you receive high-quality products.

Cross-Referencing Capabilities

In many cases, we can cross-reference Carrier coil models accurately, thanks to our comprehensive manufacturing history. If direct cross-referencing isn’t feasible, we can also work from the drawings you provide, creating a custom solution that meets your precise requirements.

Take-aways 

Replacing a Carrier chilled water coil doesn’t have to be a gamble. By collaborating with Capital Coil, you gain a reliable partner who understands the critical elements of the job: ensuring a perfect fit, optimizing performance, and getting the installation right the first time. 

For additional information or to discuss your specific coil replacement needs, feel free to reach out to the Capital Coil team. Let us help you streamline your projects and enhance your HVAC services!

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Why Cooling Coils Need to Be Replaced

Why Cooling Coils Need to Be Replaced

In theory, properly engineered and maintained cooling coils should deliver 20+ years of service life. In practice, most coils are replaced prematurely. The root causes are typically operational neglect, environmental exposure, improper application, or design limitations. Below are the three primary drivers of early replacement, along with technical context.

1. Increased Air Resistance from Coil Plugging

Cooling Coils

Failure Mechanism:

Airborne contaminants (dust, pollen, fibers, grease aerosols) penetrate beyond the fin surface and embed deep within the coil core. Once lodged between fins and tubes, they cannot be fully removed by routine air-side cleaning.

Primary Causes:

  • Poor filtration

  • Irregular filter replacement

  • Lack of annual coil cleaning

  • High-particulate environments

Performance Impact:

  • Increased air-side static pressure

  • Reduced airflow (CFM)

  • Decreased heat transfer 

  • Reduced system capacity and efficiency

Plugged cooling coils often force the fan to operate outside design conditions, increasing energy consumption while lowering cooling output.

2. Freeze Damage

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Failure Mechanism:

Water trapped in coil tubes expands during freezing, generating internal pressures sufficient to rupture copper tubes.

Why It Happens (Even When Dormant in Winter):

  • Circuiting designs that prevent full drainage

  • Drain connections positioned above low tubes

  • Lack of glycol protection

    broken return bends

  • Inadequate winterization procedures

Consequences:

  • Multiple hidden leaks

  • Thinned tube walls due to pressure expansion

  • Progressive failures after initial repair

  • High risk of recurring leaks

Once a coil experiences extensive freeze damage, repair becomes unreliable. The metallurgical integrity of the tubes is compromised, making replacement the only durable solution.

3. Corrosion

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Corrosion occurs on both the air side and the fluid side, often simultaneously.

Air-Side Corrosion

  • Salt-laden atmospheres (coastal or industrial)

  • Hydrogen sulfides (e.g., wastewater treatment facilities)

  • Chemical exposure in manufacturing environments

Visual Indicator:

A white ring around the tube-to-fin interface. This indicates loss of mechanical bond and reduced thermal conductivity between tube and fin.

Effects:

  • Reduced heat transfer

  • Loss of tube/fin contact

  • Core blockage from corrosion byproducts

  • Elevated air pressure drop

Water/Refrigerant-Side Corrosion

  • Raw, untreated water

  • High mineral content

  • Improper water chemistry control

Internal corrosion weakens tube walls and leads to pinhole leaks, particularly in copper tubing exposed to aggressive water conditions.

 

Key Takeaway

Cooling coil replacement is common—but preventable. Most failures are not random; they are the result of design limitations, environmental exposure, or maintenance gaps. Replacing a coil without diagnosing the root cause often guarantees another premature failure.

If longevity, efficiency, and reliability matter, the solution isn’t just replacement—it’s engineered improvement.

 

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Looking For A Trane Replacement Coil

If you need Trane replacement coil within a Trane system, but aren’t sure about the dimensions or decoding the model #, send this to Capital Coil & Air for pricing. On most Trane AHU’s, the AHU model #, as well as the coil or “part #”, is listed as “Service Model No Coil”. If you see this, send it over, and the sales team at Capital Coil will handle the rest. Great pricing with the ability to be built as fast as is needed!Trane replacement coil

Different Types of Steam Coils

There are two types of steam coils:  standard steam coils, which are used in most reheat applications, and steam distributing coils, which are used in applications where the entering air temperature is below 40 F degrees.  Many times, this type of coil is also known as a “non-freeze” coil, but that name is misleading because in reality, there is no such thing as “non-freeze”. 

Standard Steam

Standard steam coils operate a lot like hot water coils, but the construction is very different even if the coils appear to be constructed the same.  The supply and return connections are often on the same end like a hot water coil.  But, steam is very different than hot water, and the coil must be built for and circuited for steam.  Keep in mind that steam is always more erosive than hot water.  The brazing and tube wall thickness must account for steam. ALWAYS remember that even low pressure steam is more erosive than hot water, and a steam coil needs to be built accordingly.

Steam Distributing (Non-Freeze)

Steam distributing coils are a completely different type of coil because they are constructed as a tube within a tube. Every place that you see an outside tube or header, there is an inside tube and header that you can’t see. The steam on the inner tube keeps the condensate in the outer tube from freezing.  The purpose of the Steam Coiloriginal coil design was to distribute the steam evenly along the length of the coil and to eliminate any dead spots on the coil.  A byproduct of this coil was also found.  The coils didn’t freeze nearly as easily as the standard steam coil, so the coils became known as “non-freeze”, which as mentioned, is not completely accurate.  Any coil can freeze under the right conditions, but, this design is what needs to be used when the entering air is under 40F degrees!!! 

Steam Coil Design

Steam coil designs can be very tricky.  Steam coils are totally a function of the system and installation, while other coils operate more independently of the system.  There needs to be correctly designed traps, and they need to be installed in the correct place and depth in the system.  Often, vacuum breakers are also needed in the system.  The piping must also be installed correctly to make sure the steam is entering the coil and not the condensate.  Even with all of those factors, you’ll need a correctly designed steam coil that matches the steam pressure, length of the coil, and the entering air temperature.  Coils can freeze easily.  Coils can be too long in length and the steam cannot travel the length of the coil and distribute evenly.  Condensate can easily be trapped somewhere in the coil, and the result is water hammer. 

Capital Coil & Air has years of experience designing steam coils, and is here to answer any questions and help to design the right coil for your project! 

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HEATING SEASON WILL SOON BE UPON US

 

How to Make Sense of Heating Coils

Various winter storms have already ripped through multiple parts of the country necessitating the obvious need for working heating coils!!  With conditions such as these, emergencies with your HVAC systems are almost inevitable. THIS is precisely when you need your coil supplier to have the speed and flexibility to be able to tackle whatever emergencies arise.Steam Coil

Of all the types of HVAC coils available, heating coils are probably the easiest to select and understand. Capital Coil has listed the three most common types of heating coils that you are likely to come across.

Hot Water Coils

When looking at a water coil, the first thing to remember is that it is in effect “dumb”. In other words, water coils do not know the temperature of the water moving through it. While standard HVAC water coils are mostly constructed in the same design, the number of rows contained within the coil is a key differentiator in determining if the coil is hot water or chilled water. 99% of all hot water coils are (1) or (2) rows based on performance requirements. The “Delta T” between the entering air temperature and the hot water temperature is very large. As a result, you only need a coil with (1) or (2) rows to do the job. Face velocities across the coil can be anywhere from 600 to 1,200 FPM (feet/minute), while water velocities are usually 2-4 FPS (feet/second). As a result, you will always end up with a (1) or (2) row coil with somewhere between 8-14 fins/inch.

Booster Coils

Hot water booster coils are just another variation of the standard HVAC hot water coil.  They are always (1) or (2) rows as well, but the casing is designed for duct work installation. This basically means there is usually a 1” or 1.5” casing on all four sides of the coil. You select the proper size of the coil to make sure the air velocity across the coil is correct and simply transition the duct work to make the casing size around the coil.  Generally speaking, the size of the coil face is larger than the duct size, so you must transition the duct to make it larger. Just remember, a booster coil is nothing more than a standard hot water coil that is used for duct work installation.

There can also be a casing variation called “slip & drive”, where the coil is installed in the duct work. The coil does not have the standard casing on all four sides like a flanged coil. Capital Coil’s selection program allows you to pick either option.

Steam Coils

The real secret to any steam coil installation is to know that steam coils are much more of a product of the entire system than any other coil; meaning that other coil types are much more independent of the system.  Steam coils require numerous considerations, such as traps, pitched casing, piping flexibility, and vacuum breakers.  Steam coils are also built according to steam pressure through the tubes and headers.  2 – 50 psig is considered “low pressure” steam for coils, while 50-100 psig is considered “medium pressure”. Anything over 100 psig is considered “high pressure” steam.  An important fact to remember is that each of these categories requires a separate kind of construction with different brazing and different materials.  Additionally, almost all steam coils are (1) or (2) rows deep. Steam coils are known either as “standard” steam or “steam distributing”, but the differences are very easy to understand.  Outside air temperatures below 40˚F require that you have a “non-freeze” steam distributing coil.

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Top 10 Fan Coil FAQ’s

1. A fan coil is among the easiest units to understand in the HVAC industry.  Basically, there is a small forward curved fan, a coil, and sometimes a filter.  They are all direct drive units. Click HERE to see Capital Coil’s full Fan Coil Product Lineup.

2.  Fan coils run from 200 CFM to 2200 CFM, which is 0.5 ton through 5.5 tons.  Anything larger than these sizes requires a belt drive unit…which is really a full fledged air handler.

3.  The thing that differentiates fan coil units is where and how they are going to be installed.  Is the unit going to be hidden above the ceiling or maybe in a closet?  Or is it going to be exposed so that everyone can see it?  Will it be ducted or will it just pull air from the space where it’s located?  These are things that determine the configuration of the unit and which style of unit to choose.  But, every unit has 3 things in common:  fan, coil, and sometimes a filter.

Fan Coil 4.  Some units have (2) coils.  One for heating and one for cooling.  Obviously, there is a separate supply and return connection for each coil and these units are known as 4 pipe fan coils.  Many units only use the same coil for both heating and cooling and these units are 2 pipe fan coils.

5.  Units are either horizontal or vertical depending on the orientation and flow of the air.  A typical fan coil in a hotel room is a vertical unit with a mixture of air coming from outside and the air recirculating in the room.  The air enters at the bottom of the unit and is drawn upward through the fan.  This makes the unit a vertical style.  Many units are horizontal with the air entering at the back of the unit and traveling horizontally through the unit.

6.  Almost all fan coils are 3 speed or infinite speed settings based on the controls.  The high speed gives you more BTU’s, but more noise too.  Because the unit is direct drive, when you dial down the speed, you also dial down the performance.

7.  Coils in the units tend to be 3 or 4 row deep coils.  3 row is typically used the most, but if you need the extra performance, 4 row is the way to go.  Performance is always governed by the cooling aspect.

8.  Fan coils sometimes have short runs of duct work and there is static pressure on the unit.  Static pressure reduces the amount of CFM and BTU’s that the fan coil can give you.  This is true of both horizontal and vertical units.  Most performances listed on charts that you will see are static free performances.

9.  The control systems for fan coils are often more complicated and more expensive than the units themselves.  There are balancing valves, isolation valves, unions, y-strainers, p/t plugs, air vents, ball valves, thermostats, condensate float switches, and disconnects.  Capital Coil & Air can do this at the plant, but it is much cheaper and easier to do it at the installation. 

10.  Just describe your installation requirements to a sales engineer at Capital Coil & Air and they will guide you to the right design and configuration of the unit for you.  It requires only a phone call or e-mail! We look forward to working with you!

 

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Case Study – Replacement DX Coils at local Mushroom Farms

Replacement DX Coils: To those not aware, Kennett Square, PA is the mushroom growing capital OF THE WORLD! Kennett Square is also located quite close to Capital Coil’s sales office in West Chester, PA, and we get multiple requests per month to personally come out and measure DX coils that need to be replaced at these farms.

Mushrooms need a well-ventilated growing environment, and poor ventilation can lead to higher levels of CO2. Higher CO2 levels negatively affect mushroom quality and growth. Ensuring proper air circulation is essential for maintaining healthy crops. Mushrooms also thrive in high-humidity environments, but excessive moisture can also lead to mold or bacterial growth, which can damage the entire crop. Proper humidity control is crucial to maintaining the right balance and preventing costly losses. To tackle these problems, growers need reliable climate control systems, and that’s where Capital Coil steps in.

Mushroom cultivation, while lucrative, is not without its challenges. Running climate control systems for mushroom farming can be expensive, especially when using inefficient equipment. High energy costs can eat into profits, particularly for smaller, family-owned operations. One of the biggest challenges for mushroom farmers is making sure that the coils are working at peak efficiency because the conditions in and around those farms will corrode the aluminum fins at a faster pace than most other environments. As mentioned above, there are very specific conditions that need to be maintained for a successful crop, so the coils in the condensing systems that are needed to sustain those conditions have to be working at all times. 

One farm had been trying to repair numerous coils through different “band-aid” methods. None of these attempts worked, and the farm’s energy costs had skyrocketed when trying to get the same capacity from a failing coil.  One of the neighboring farms that had used us for numerous DX coil replacements recommended that they call Capital Coil to come out and assess the failing coils.DX Coils

After looking at a few of the units, most of the coils’ finned area had been eaten away by corrosive elements in the air. The OEM had not recommended any protection for the coils, which was why they failed far sooner than they should have. The new coils were to be installed in the original units, so the measurements needed to be exact. I also explained to them that any new coil(s) needed to either have more durable materials, such as stainless-steel casing and/or copper fins, or a protective coating for the whole coil. If not, these same issues would continue to occur.

The farm decided to order (1) DX coil with an epoxy coating as a “test” before ordering the rest. The new DX coil arrived a few weeks later and was a perfect match for the original unit. A year later it was still running at max capacity with zero damage to the finned area because of the coating.

Due to the speed that we were able to come out to the site, correctly assess the reasons for the coil failures, and make recommendations on increasing the coil’s longevity, they decided to order the remaining batch of DX coils from Capital Coil & Air. They also recommended us to many of the other farms in the area, so Capital Coil is now the main HVAC coil replacement company for many of the largest mushroom farms in the United States.

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Top 10 Chilled Water Coil Facts

Every Chilled Water Coil selection is about balance. Your coil selection balances the rows/fins versus the cost of the coil pressure drops/performance. Trying to cut corners on your initial selection may save you money upfront, but you will inevitably pay it back down the line through added energy costs. This is a truism for every manufactured coil.

  1. Fins cost less money than rows/tubes. A good cost-cutting tool when selecting a coil is to choose 14 fins/inch. This will turn your (8) row coil into a (6) row coil, which will dramatically lower your costs. If you choose to go this route, one thing to keep in mind is that 14 fins/inch will be semi-inconvenient to any maintenance crew tasked with cleaning the coil. Don’t expect a Christmas card from them that year.
  2. That raises the question of whether or not you can even clean a deep (6) or (8) row coil? In short, you can, but it is not easy. Chilled water coils are especially difficult to clean because they are almost always wet. Due to this fact, they typically attract dirt and additional particles that other coils do not. Generally, when cleaning a coil, most of the dirt get pushed to the middle, and for that reason, 14 fins/inch may not be the best idea after all.

    Chilled Water Coils

  3. Did you know that fins do approximately 70% of the heat transfer in a chilled water coil, while the tubes are only responsible for the remaining 30%? This is precisely why the fin/tube bond is so important. Without a perfectly crafted fin/tube bond, coils become inefficient very quickly. You pay for that inefficiency through increased energy costs.
  4. How long does a coil last? At what age can I expect my coil to fail? Unfortunately, there is no single answer to either question. Everything is dependent on a combination of maintenance, duty, and numerous other factors. If your initial selection was correctly chosen, and proper maintenance was kept, 15-20 years is a good timeframe.
  5. You may have a situation where your coil is 20 years old, and everything appears to be operating in good condition. There are no leaks and all looks ok. However, over that length of time, what you don’t see is that the fins have thinned and are no longer bonded to the tubes, and the coil is dirty in places that you cannot see. Again, while the coil may look to be running in top form, it’s probably only running at 60% capacity. Most likely, the tubes have also thinned over time, so when the next deep freeze occurs, you can guess the likely outcome.
  6. You really need to replace the coil, but have been told to make do with the current coil? To make up for the lack of efficiency, you might try to “jury-rig” your system. One method is to change the drive on the fans to deliver more CFM. This increases the air pressure drop, which in turn increases motor brake horsepower. Another option to help increase the coil’s efficiency is to lower the temperature of the chilled water from the chiller. We tend to mess with the system and apply temporary Band-Aids, when replacing the coil is the only guaranteed long-term solution.
  7. If you want to spend money wisely on a chilled water coil, simply make the tubes thicker. The tube thickness for a 5/8” tube coil is .020” thick, so increase the tube thickness to .025”. The same applies for a ½” tube coil, with a tube thickness of .016”. Increase it to .020”. By doing this, you get the added bonus of making your return bends thicker, which also helps to extend the life of the coil.
  8. Not quite sure about circuiting on a chilled water coil? You are going to have a hard time making an accurate selection unless you understand how to circuit a coil. Circuiting is really nothing more than selecting the number of tubes that you want to feed, and how many passes the water makes through the coil – depending on your GPM. Circuiting is one of the most important factors in ensuring that your coil is running at peak-performance.
  9. Curious about the balance between cost, size, materials, and maintenance? Every chilled water coil needs to be maintained for its entire life-span. If you’ve made your selection, and something seems off about the coils, chances are mistakes were made during the selection process. Some indicators include the coil being too big for the space allowed, or incurring out of control energy costs. What is the point of saving $500 on a chilled water coil if you have to spend $5,000 in maintenance over its life-span?

As coil replacement experts, we run into this issue every day. Our goal is to work with you to ensure your selections are correct the first time. The person in charge of budgets will be grateful to you over time. Capital Coil & Air welcomes the opportunity to work with you on your next coil project! We want to be your coil replacement specialists.

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Now Offering R-454B Refrigerant for All DX Coils

In keeping with most of the OEM’s in 2025, Capital Coil is helping everyone transition from R-410A over to R-454B refrigerant in their DX Coils. Whether you are designing a new system, or retrofitting an existing one with a condensing system, Capital Coil can help in making the switch in refrigerants.DX Coils

If you are not yet aware, the EPA is working hand in hand with many of the major OEM’s to help reduce commercial HVAC’s carbon footprint. One of the major ways in which HVAC manufacturers are helping and complying with the new industry standards is the gradual change in refrigerants from R-410A to R-454B. Beginning in January, 2025, no new system is allowed to be built or imported using the older refrigerants. Without going into a deep dive on the differences, R-454B offers a lower GWP (global warming potential) alternative to R-410A. Hence the mandate to change to that refrigerant type. 

However, Capital Coil will still offer R-22 and R-410A for DX Coils in older systems that might not be compatible with R-454B. In other words, Capital Coil has been, and will remain, the most reliable source for all commercial and OEM replacement coils. Our #1 job is to make to your job easier, so please reach out. You will be glad you did.

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