When the name of the game is “heat exchangers,” preventative maintenance isn’t just a good idea, it’s essential. If you don’t take care of your investment, the very device that was designed to save you countless dollars could reward your negligent care with a hefty price tag.
In many heat exchangers, one of the most dangerous things that can go wrong is cracking. For example, a crack in a home furnace’s heat exchanger could allow dangerous gases, such as carbon monoxide, that were supposed to exit through the exhaust to mix with the household air. The contamination of the house’s air supply with this colorless and odorless gas could create a lethal environment within the home. In an industrial heat exchanger, a crack could lead to a buildup in pressure to compensate for lost efficiency, open valves which could become fouled and stuck open, or unsafe heating levels. These simple compensations by your system could lead to completely failed components, injury, or worse.
How Do Heat Exchangers Crack?
The best way to prevent a crack in your heat exchanger is to understand the types of situations that are likely to cause the cracks in the first place.
- The most common way cracks form is due to an issue that cannot really be prevented, but, thankfully, it can be caught before the breakdown gets serious. The culprit: frequent use. This is the old “wear and tear” situation. No parts are designed to last forever, and the constant expansion and contraction of components can stress any metal to the point of cracking. When properly maintained, the chances of this occurring are significantly reduced, but even the best systems wear out eventually.
There are some issues that lead to a premature cracking.
- Problems with combustion cause inefficient heating. When the heating process is inefficient, the heat exchanger must compensate for this inefficiency. Most exchangers have high and low heat thresholds. The temperature should remain somewhere in the middle, but poor combustion requires longer and hotter burning. The additional use of the heat exchanger at higher temperatures places excessive stress on the metals, which will eventually lead to cracking.
- Poor air flow. Heat exchangers are just one part of a system. In many heat exchangers, air flows over the exterior of the heat exchanger to draw off heat. When the airflow that is supposed to be coming through the vents is reduced by dirty vents or filters, then the heat transfer is inefficient. This places extra work on the other parts of the system, excess heat, and eventually cracking.
- Dirty heat exchangers can be as troublesome as dirty vents and filters. While the dirty vents and filters prevent sufficient air from getting to the heat exchanger to help cool it off, a dirty exchanger has the same problem for the opposite reason. Even if enough air makes it to the heat exchanger, dirt, grime, and buildup on the heat exchanger itself prevent the air from contacting the metal and drawing off the heat.
- Heat exchangers can get dirty on the outside, but they can get dirty on the inside, too. The dirty buildup is known as fouling. Fouling is caused when particles in the exchanger fluid accumulate or even bake onto the surface of the heat transfer surface. It can occur on shells, tubes, plates, or a combination of all of them.
To compensate for the fouled surfaces, the flow rate needs to increase, the heat needs to increase, the control valve may remain open, etc. In the end, it doesn’t matter where the fouling was or how the system compensated for the lack of efficiency—the results will be the same: damaged exchangers that can cause injury or worse.
Preventing a Cracked Heat Exchanger
The most effective way to prevent a cracked heat exchanger is through proper preventative maintenance.
- Exterior cleaning. To prevent clogged vents and filters, exterior cleaning should be completed every year. Fresh filters keep the airflow moving as designed. A clean exterior ensures that the air can reach the surface of the exchanger and cool it as intended.
- Interior cleaning. Whether you choose a chemical clean, a steam-out, hydro-blasting, or another method, you need to ensure you have somebody who is knowledgeable about the proper cleaning and maintenance of heat exchangers. The use of the wrong chemical or the improper sealing of the exchange unit could not only cost you massive amounts of money, but it could cost somebody their life.
- Inspection. There are a number of ways to check for cracks. From a smoke check, chemical dye, or even scented fume test, the result is the same. No leaks means good news; leaks means bad news. Either way, you will be able to avoid costly damage to your unit if you find a potential problem and get it fixed before there is a complete crack or failure.
Heat exchangers are an investment that can save you hundreds of dollars each year in a home, or many millions of dollars each year in an industry. Protecting your investment is just as important as regular maintenance for your vehicle. You wouldn’t entrust a Ferrari to the local auto shop on the corner just because they had the right set of wrenches. Don’t entrust your heat exchanger maintenance or repair to anybody but professionals who are specially trained and come with exceptional references.
When proper standards of care are taken, the risks associated with dirty, fouled, or cracked heat exchangers are minimized and even eliminated. While this looks great on your safety report, it looks even better on your bottom line, as you save more in the long run on maintenance costs, injuries, and downtime from inefficient or broken components.