Now, as you can see, it basically looks like a rack that you then set your logs on to burn. So the next question you are asking is, why do I need a fireplace heat exchanger? To answer that question, you first need to understand the physics behind how a fire burns, and how a fireplace heats your home. For the fire to burn, it needs air. The fire draws this air in from the room that the fireplace is located in. That means the fire is pulling air out of your room in order to burn. The air in your room is replaced by outside air that leaks in through the spaces in your doors and windows. The fireplace is also designed to release exhaust through the flue and chimney. So to recap, air gets pulled FROM outside, INTO your house, UP the chimney, and OUT.

This isn’t very effective at doing much of anything other than heating the area just above your chimney. Of course, you don’t want to capture the air going out your chimney, because you would quickly die of smoke inhalation and carbon monoxide poisoning, but you do want to capture a higher percentage of the heat that is escaping. A fireplace heat exchanger is designed to do this by becoming a ventilation system that blows the heated air directly into your room. Here’s a better look at the fireplace heat exchanger unit.

So here you can see, it is a system of tubes that are combined with an electrical fan system. The idea is that the tubes heat, and the fans on the bottom draw air in the tubes, then force the air out through the top of the tubes. This is a classic model of a simple tube heat exchanger. As I have mentioned before there are many varieties of heat exchangers. The fireplace heat exchangers are a type of tube heat exchangers.

By using a fireplace heat exchanger, you should be able to increase the efficiency of your fireplace because more air gets forced back into your room, rather than up your chimney and out. Do they really work? Well, my feelings on the issue are that you would be much better off installing a fireplace stove insert in order to have a more efficient fireplace.

Inserts basically are a kit that converts a masonry fireplace into a wood burning stove. I’m sure you have seen the classic stand alone wood burning stove. Well, a fireplace insert gives your fireplace a face that is similar to the free standing variety, but of course, in the back it is still your masonry fireplace. I believe that these are significantly more effective and efficient than a fireplace heat exchanger, however, if you prefer the aesthetics of an open fireplace, then you are much better off using a fireplace heat exchanger over the alternative of nothing at all.

I don’t have a fireplace where we live right now, but my family had one of these stove inserts when I was growing up. It looked a lot like the one pictured here. As you can see, there is a vent system, so just like the fireplace heat exchanger, you have a forced air delivery system. Man, these things can really pump out the heat. So, I would really recommend one of these, but if you are insistent on having the look and feel of an open hearth, then I certainly would not want to forgo getting a fireplace heat exchanger.

The engines of ships need to be cooled, just like with any other type of engine, although they usually use the water that they are navigating through in order to keep the engine cool. This means that ships and boats need to be properly equipped to prevent water leaking into the interior of the ship. If any cracks or leaks arise, it is possible for water to seep into the air system or the water system. The result can be that the boat or ship fills with water creating a sink hazard. Additionally, salts and minerals, and other debris can clog the cooling system. This includes aquatic plant and animal life, garbage, and mollusks. It can be extremely difficult to clean the heat exchanger tubes on a large ship. It’s not a task for a novice. It takes high level expertise and the correct heat exchanger cleaning equipment. Therefore, it is best to stay on a rigid maintenance schedule of heat exchanger cleaning.

In order to clean air to water heat exchangers, a high level of expertise is required because it is a labor intensive job that requires the technician to get access to the heat exchanger tubes and use a variety of heat exchanger cleaning equipment, which will include metal and plastic scrapers, chemical solutions, brushes, water jets. Before the job even begins, the heat exchanger tubes must be inspected to determine what equipment and manpower will be needed.

There are all sizes of heat exchangers because they are used in all sizes of boats and ships, from small recreational craft, to large tankers and aircraft carriers. Logically, the size of the heat exchanger tubes are relative to the size and needs of the boat. Some tubes are even less than one inch in diameter, while others are large enough for a adult male to fit clear inside. They can be hundreds of feet long too. The heat exchanger tubes that is, not the adult males. The tubes can also be constructed from a variety of different metals, which will be part of assessing the best cleaning method. It will also be considered as to whether there is a need to recoat the tubes. These are all variables that need to be taken into consideration before planning the best heat exchanger cleaning equipment for the job.

Old School Tube Cleaning Vs. New Techniques

With the older heat exchanger tube cleaning technologies, tube cleaning was not always very good, and refouling of the tubes would often happen very soon after cleaning because of the inefficiency of the cleaning. This is because the main method was water jetting. This method pushes water through the tubes in a single direction, and as a result, it was possible for the build up that was being cleared out. This method also created an increased need to recoat the surface, because it left some of the contamination on the sides of the tubes, leaving the tubes prone to corrosion. Some of the recoating was just putting a new surface right over top of the contaminants. This is like painting over a rust spot on your car. If you don’t remove all the rust, the new paint won’t take very well. The result was a high likelihood of refouling of the tubes.

New methods use a much higher pressure and employ the use of a rotating head, which clears the inner walls more completely because the head is in constant rotation. Therefore, the recoating takes better because it is on a much more effectively cleaned surface. In many cases the tube is nearly like new after the recoating has been completed.

There is also an environmental benefit to this method, as it only uses water to clean the heat exchanger tubes. There are no toxic chemicals used which is both eco-friendly, and more cost effective than using expensive and harmful chemicals. Our oceans and seas are the foundation for life on this planet, so this is a very important consideration. This method can be used for all metals, whether it is a soft brass or hard titanium, and it will not harm the metals used.

After a thorough heat exchanger cleaning, it is important to perform a extensive inspection. This is the time to detect leaks that were not noticed prior to cleaning. It is also an opportunity for the boat owner to see if the cleaning company has done their job well. This inspection is most often done with tiny robotic cameras. Other types of inspection include manual underwater inspections of the outer areas of the heat exchanger. The inspection allows the ship to be cleared as confirmed that the heat exchanger has been properly maintained, and the ship is seaworthy.

Heat exchanger tube cleaning is an essential part of the maintenance and service schedule of a boat or ship that ensures proper functioning of the ships engine. There have been many advances in heat exchanger cleaning equipment that have greatly increased the efficiency of heat exchanger tube cleaning, and simultaneously decreased the cost and reduced it’s environmental impact. Whether it is a small recreational craft, or a large military or industrial ship, it needs this important service on a regular basis in order to stay operational.

The oil refinery business is the epitome of big business. There are many types of expensive and specialized equipment that is used throughout all the stages, and the price tag becomes even bigger with off shore rigging. Although heat exchangers are a part of every device that transfers heat from one fluid to another, the shell and tube heat exchangers that are used in industry are especially important to maintain.

When a rig or plant needs to go down for maintenance, as I mentioned before, it costs thousands of dollars per hour. As a result, it remains a common industry practice to try and just use the heat exchanger as long as possible, even when the efficiency has dropped below 40%. Plants just do not want to shut down until heat exchanger tube cleaning becomes an absolute necessity.

Another standard practice is to shut down for a period of 21 days when they finally do go offline for maintenance and tube cleaning. This is really the standard more because it’s the way it’s always been done than because it is actually the best way to do things. Now, take into account the cost of down time, and ask yourself just what kind of cost you think is incurred by a 21 day shutdown. Now, just keep that thought in the back of your mind.

The old standby method of tube cleaning is pressure jetting water and essentially knocking loose all the scaling that has caused the fouling. This is an inefficient method. Although it does sort of work, it is difficult to get the u-bends satisfactorily and efficiently defouled.

Full replacement of a shell and tube heat exchanger is costly. Cutting off u-bends and rewelding them is inefficient, and sometimes either tricky or dangerous, depending on the logistics of the placement. Pressure jetting is outdated. So what can be done?

Recent developments in tube cleaning equipment technology can now allow shell and tube heat exchanger cleaning to be completed in just 3 hours. New methods include foam cleaning, laser cleaning, and newer “smart” technologies that can tell the difference between buildup that needs to be removed, and the surface of the tube itself. The “smart” metals back off when they get through the fouling, leaving the shell and tube heat exchanger intact.

By using newer technologies, and rethinking the old ways, plants can have more efficient output of their heat exchangers, less downtime, and more efficient tube cleaning. Especially with fuel costs rising as they are, it is time for the industry to take a look at more efficient tube cleaning equipment that will save money on the production end. Hopefully this savings will then pass on to the consumer.

Heat exchangers often go so long without being properly cleaned and maintained that by the time there is a heat exchanger cleaning, the original specs and records have been lost or misplaced. This creates an additional problem, because without the original specs, no one knows what kind of performance the heat exchanger is supposed to have.

Once the heat exchanger finally is opened up for cleaning, it’s common to find that it has become so fouled that the heat exchanger cleaning takes significantly longer than it would have if it had been regularly maintained and cleaned. Ultimately, the lack of regular maintenance and cleaning results in a higher cost, longer cleaning duration, and greater loss of production.

This might sound like some sort of a rare, worst case scenario, but it’s entirely routine for the specialis cleaning companies. When cleaning is done, it’s often done without any real knowledge of what kind of performance benefit there will be, and how long this increased efficiency will last.

One of the most used heat exchanger configurations in industrial use is the straight of hairpin shell-and-tube-exchanger. This has bundles of hundreds or thousands of small-bore tubes. Even a moderate amount of scaling can take considerable cleaning and effort to return the heat exchanger back to optimal performance. If the outside of the bundle has heavy scaling, it’s exponentially more difficult to adequately clean the heat exchanger.

Advancements in design would be able to make heat exchanger cleaning faster, safer, and result in better waste containment. This would result in less time spent offline, and better performance.

Currently, heat exchangers are generally designed to have the capacity to operate even when they are significanly fouled. They are designed to operate with about 30% or 40% excess capacity. This is what industrial facilities want. They prioritize continued functionality over ease of maintenance and cleaning. Heat exchangers are designed and installed to use one of 3 methods of cleaning: mechanical, chemical, or pressure-jetting. This has been the standard for over 50 years.

Refineries, like other industries, use a 21 say shutdown process during which maintenance, including heat exchanger cleaning is done. This is the way it has been done for decades. Industry continues to use the same methods for heat exchanger cleaning that it has always used. The primary method is pressure washing with water.

It’s normal for a company to have their heat exchangers designed to continue running, even if not at optimal performance, instead of having them designed for efficiency, or ease of cleaning. This could require more frequent cleaning, but it would be easier, safer, and more cost effective, resulting in a more efficiently performing heat exchanger. BP (British Petroleum) was able to cut cleaning time of a shell and tube heat exchanger down to 3 hours by changing their heat exchanger cleaning method. Prior to that, cleaning would take 3 days.

If a company designs their heat exchangers for ease of cleaning and maintenance, the plant can remain at near full production capacity throughout the duration of the cleaning process. Banks of heat exchangers can be taken offline, while the rest remain on line. Heat exchangers designed to allow the header to be removed allows for heat exchanger cleaning with alternate methods to the usual high pressure water jet. This can cut heat exchanger cleaning time down to just a few hours, instead of a few days.

More frequent cleaning can also reduce the occurrence of heat exchanger fouling, and also minimizes the amount of time that the tubes are exposed to open air during cleaning. This results in a reduction of corrosion of the heat exchanger tubes.

Cleaner, smoother heat exchanger surfaces allow for more efficient heat transfer. When fouling does occur, it is easier and less time consuming to do the heat exchanger cleaning, and also allows for a wider variety of cleaning methods.

Generally, plants have heat exchanger cleaning intervals of 3 or 4 years. Unfortunately, spreading out the time period between cleanings winds up with a greater cost, not a lesser one. In the short term, it seems like a good idea to stay fully operational, but when the time for maintenance finally does come, down time, lost productivity, and cost is significantly higher than the shorter down times of a quicker maintenance schedule would be. Long maintenance schedules result in a much bigger job.

Big picture thinking, and better design can ultimately be a huge advantage in minimizing the cost of heat exchanger cleaning.

The part of your furnace that heats up is the heat exchanger. As the air or water that carries heat through your home passes the heat exchanger, it heats up. The forced air, or water carries itself throughout your home and keeps it warm. On the inside of the heat exchanger, the combustion process occurs. To the outside of the heat exchanger wall, water or air passes by and get warmed as it then distributes to the rest of your home.

Since the combustion process happens inside the heat exchanger, there are many toxic gases contained inside the walls. Carbon Monoxide is one of these deadly gases. If the heat exchanger becomes cracked or warped, these gases can escape from the inside, and get into the ventilation system, or simply permeate throughout your home. Carbon Monoxide is both deadly and odorless, so you won’t be aware of carbon monoxide poisoning from noticing a funny smell. You will notice the effects, however. Some of the symptoms are nausea, dizzyness, and other flu like symptoms. You need to catch carbon monoxide poisoning early, or you will die, so a good carbon monoxide detector is inexpensive and well worth the cost.

Many modern furnaces have a lifespan of about 15 years, however, poor maintenance is sure to shorten this time frame. Rust can form in the heat exchanger if condensate from the evaporator seeps in. Dust and dirt can form on the high limit switch. This will cause the furnace to switch off and on more frequently. Dirty furnace filters can reduce air flow, and cause your heat exchanger to run too hot. This will also cause the furnace to switch off and on more often. Dirty burners will decrease the flame efficiency, and lead to a build up of soot on the heat exchanger. Any of these conditions will reduce the lifespan of your heat exchanger, and make it more prone to cracking or warping.

Yearly servicing of your furnace is the best defense against these conditions that reduce the lifespan of your furnace. Have a certified Heating Ventilation and Air Conditioning (HVAC) technician check your unit prior to the heating season each year. A certified HVAC technician will know what to look for in inspecting your furnace, and can tell if there will soon be a problem with your heat exchanger.

If your furnace is over 10 years old, it is especially important to have annual checks of the health and safety of your unit. The heat exchanger is made of metal, and it expands as it heats up. When the furnace shuts off, the metal cools and contracts. This happens each and every time the furnace turns on, and back off. Over the course of years, this amounts to thousands of times that your heat exchanger is expanding and contracting. At some point, the metal can no longer take the stress of continued expanding and contracting, and the heat exchanger walls crack, or warp. If this happens, there is the danger of Carbon Monoxide poisoning mentioned earlier. This is most certainly no laughing matter. Keeping your furnace properly maintained can be the best plan for a long life, for both you and your furnace.

Your furnace burns gas, natural gas, or oil, or runs on electricity, which then produces heat. The heat exchanger is the containment system for this heat source. As the air or water flows past the heat exchanger, the air or water heats up, just like putting a pot of water on a stove. In essence, the heat exchanger is the heart of your furnace. In most furnaces, the heat exchanger is hidden from view.

In a gasoline furnace you would find:

• Solid state furnace control – This is an electrical component which has a fan assembly. you can find it in the rear of your furnace.
• Draft inducer – This uses a fan to force air through.
• Igniter and flame sensor
• Gas valve, manifold, gas burners

Surrounding all these components is the heat exchanger. Then the furnace filters, and other air filters. Some of the components may vary a bit, depending on the exact type of furnace you have, but this is the basic diagram of a home heating system.

Usually, a heat exchanger will fail because of warping or cracking of the metal walls of the heat exchanger. When the furnace runs, the metal expands, and during off cycles, the metal contracts. As your furnace runs on and off, the heat exchanger expands and contracts over and over. Eventually, this repeated expanding and contracting can result in failure of the integrity of the metal walls of the heat exchanger.

When the heat exchanger warps or cracks, it can lead to an escape of toxic exhaust gases, including carbon monoxide (CO). Most heat exchangers can last a very long time. With proper maintenance of your home heating system, it can even last longer than the average life expectancy. In fact, regular cleaning and maintenance can be the primary factor in the life span of a heat exchanger.

Reduced airflow can also be a major factor in premature failure of a heat exchanger. Dirty furnace filters are the most common cause of impaired air flow. Also contributing are obstructions and dirt in the air vent or duct work, dirty fan blade, and dirty, worn fan motors. All these factors will reduce the efficiency and lifespan of the heat exchanger.

When airflow is reduced, the heat exchanger, and other components can overheat. Most heating systems will have a preset limit switch that will cause the unit to shut off if it gets too hot, but if it is operating outside the optimal parameters, it can still lead to additional strain and metal fatigue of the heat exchanger.

The best way to maximize the lifespan of your heat exchanger is to inspect it every year prior to the heating season. Monthly cleaning of your furnace filters is also recommended. Always use a qualified service technician to inspect your furnace. The cost is reasonable and affordable, especially compared to the cost of allowing your heat exchanger to fail. Carbon Monoxide detectors are also a valuable and inexpensive precaution to indicate carbon Monoxide leaks.

Always refer to manuals, manufacturer specifications, and use the proper heat exchanger cleaning equipment.

Where is my furnace filter located?

Every heating system has one, whether it’s an oil furnace, electric furnace, or gas furnace. In some cases, it may take some detective work in locating your furnace filter. Sometimes even HVAC professionals can have difficulty in locating the furnace filter. Rest assured, it’s in there, even if it’s in a rather hidden location.

Typically, the furnace filter is somewhere near the fan. This is because the purpose of a furnace filter is to keep dust and particles out of the fan. The furnace filter can be almost anywhere as long as it is “upstream” from the fan. In other words, somewhere the air will flow through prior to reaching the fan.

You furnace filter may be located inside a duct opening, behind a panel, or even behind other equipment, hidden from view. In older heating systems, it is common to place the furnace filter in the duct system, upstream from the air handler. You can locate the furnace filter by starting at the air handler and work backwards until you find it. You might find the furnace filter at the opening of the return air grill, or just behind the return air grill.

You should be able to determine the location of the furnace filter by resolving which duct is the return duct. The return duct is the one that pull air into it. The furnace filter should be somewhere between this opening and the air handler.

There are cases where no furnace filter is present. It may have been removed instead of replaced, or it may have never been installed in the first place. If this is the situation, your furnace will need to be inspected to ensure that it is still capable of operating safely.

A properly maintained furnace filter is necessary to allow for good airflow past the heat exchanger. Having a poorly maintained furnace filter, or even no furnace filter at all can create a dangerous situation. The reduced airflow past the heat exchanger can cause the heat exchanger to overheat, and result in a cracked or warped heat exchanger.

In worst cases scenarios, a cracked or warped heat exchanger could leak carbon monoxide, or start a fire. Both of these situations can be deadly! For more information on the safety issues, see Safety: A Reason to Keep Your Heat Exchanger Clean

A bad, or missing filter will also cuase your heating equipment to operate inefficiently, and that is an added cost as well. One way or another, it will be much less costly to properly maintain your furnace filter.

Just like any other heating and air conditioning equipment, gas and oil furnaces need a certain level of unrestricted air flow in order to function efficiently. Air flow is measured in Cubic Feet per Minute (CFM). Inside your furnace is a heat exchanger. The heat exchanger has the flame and heat source on the inside. Air flows past the heat exchanger on the outside. As the air flows by the heat exchanger, the air warms, and is directed to the other parts of your home. This heats your home.

The walls of your heat exchanger are made as thin as possible, while still being capable of withstanding the heat of normal operation. But normal operation requires a certain level of air flow.

When the furnace filter has been in use so long that it begins to restrict the airflow, a dangerous situation starts to arise. As the amount of airflow past the heat exchanger decreases, so does the ability of the heat exchanger to keep cool enough to maintain its structural integrity. The process I described earlier works two ways, not only is the air flowing past the heat exchanger warming, but the air flow itself is also cooling the heat exchanger, and keeping it within specified operating temperature range.

Now, with the restricted air flow, the the heat exchanger runs hotter. The hotter it runs, the more the walls of the heat exchanger expand while running. It contracts back down as it cools during an “off” cycle, but the metal was not designed to expand and contract in that wide of a range. The result of this added expansion and contraction of the heat exchanger is that the walls of the heat exchanger crack or warp. Once it cracks or warps, combustion gases escape the inside of the heat exchanger and mix with the air being delivered to your home.

Fortunately, reputable companies design furnaces to have a safety switch that will shut down the heat exchanger when it reaches a certain temperature. This prevents the unit from even being able to run too hot. The limit switch is located near the heat exchanger and is preset to shut off if it reaches a pre-set temperature. The unit will stay off until the switch is either manually reset, or the temperature drops back to within the safe limit. In this case the switch will reset automatically.

Furnaces can operate for quite a long time, turning off because the limit was reached, and resetting automatically. Technically, the furnace is not running within the limits of it’s design, but the homeowner fails to notice, because the furnace continues to operate. For this reason, most furnaces are now designed to require a manual reset. This way the homeowner knows that the furnace must be serviced, because it will no longer operate until it is fixed.

However, it is wise not to rely on these safety switches to protect you. Just as any other mechanical unit, the safety switches can occasionally fail. Please, for your safety, regularly clean or change your furnace filter. Follow manufacturer guidelines, and using the proper heat exchanger cleaning equipment.