Preventative Maintenance

We all know somebody who is into gizmos and gadgets. They have to have the latest of the newest whether they really have a need or not. Usually it's hard to warrant a need for most of the consumer electronics but marketing keeps us believing we can't live without these great gadgets. There are now almost 2 billion cell phones in the world and the use keeps on growing. Yet 10 years ago almost nobody had one. Sometimes I wish cell phones were never available. But I've been starting to believe these technological advances are coming from beings on other planets because it's just difficult to understand where all the inventors and geniuses are coming from that are creating these gizmos and gadgets. Especially all the technological advances in technology, medical, manufacturing and military technologies. Is this really human? I continually see new computer technologies and software with new software updates while I'm still coping with the first releases. I'm not only perplexed at the continual growth in the software industry but who are these people that have mastered all the technological advances of these programs that I have to need more? Did I get dumber or did the rest of the world get smarter? I don't see the people in my little world getting smarter. In fact the opposite has been my observation. So it must be Martians or beings from another planet.

Then after seeing all these technological marvels I see recent reports more people are being maltreated in hospitals by doctors and nurses than at any other time. After all these technological advances? This same recent report says the equivalent of a jumbo jet load of people die every day from staph infections due to doctors simply not washing their hands before examining patients or surgeries. It's reports like this that make me question if we are responsible for all these technological miracles when doctors can't or won't take time to wash their hands.  

But technological advances have been slow to be accepted in the HVAC industry unlike other markets? Why? The technicians in our industry have difficulty even accepting their own responsibility to do a basic Manual J load calculation to determine the correct size system to be used. In fact to go along with the technological advances that have taken place in so many other industries it is more important those technologies are reliable, useful and perform in all types of environments for the HVAC industry. Many of those technologies have proven reliable useful performance with variable speed ECM blower motors now having over 15 years of reliable service.  With two stage air conditioning, intelligent solid state igniter controls and ultra efficient condensing gas furnaces it's exciting to see where technological advances can be used successfully in HVAC systems. But most contractors only propose the basic builders model equipment. Why? A certain mind set has developed in HVAC contractors that homeowners aren't interested in spending extra money for more efficiency and technology. They think it's all about the lowest price. But if that were true than only the most competitive priced brands would sell the most equipment. And that's not true. The reason HVAC contractors don't sell more high technology equipment and systems is because they don't bother to show homeowners a value and return on their investment. In other words if contractors and technicians don't embrace the technologies themselves how do they expect their customers to do so? There has been more recent marketing by some HVAC contractors in light of the recent energy crises but on the whole most have little marketing skills and rely entirely on the manufacturers they represent to do it for them. The manufacturer's goals at marketing the new technologies haven't exactly been stellar either.

So in light of all the technological advances and developments the HVAC industry isn't really much different than the medical profession. Where all have failed is in educating homeowners about the need to keep their systems clean. Yes in spite of all the latest technological advancements most homeowners don't bother to change air filters or keep their systems in 100% operating condition. Preventative maintenance is the third biggest cause of system failures in the HVAC industry. The first two problems of oversizing of equipment and undersized air distribution systems can be blamed on HVAC contractors but lack of preventative maintenance is the single biggest homeowner related item that causes system failures. A dirty filter can reduce efficiency of a system by 50% or more. Dirty coils and clogged heat exchangers not only waste energy but destroy the equipment. 

Unless attention is paid to the basic preventative maintenance of existing systems homeowners cannot expect new equipment to magically create continual energy conservation and longevity. Understanding the role of the homeowner in preventative maintenance is as important as the equipment itself. Homeowners often times feel their only role is to change filters, check the thermostat setting and make certain diffusers are open and unobstructed. Yet most technicians report that simply finding the furnace or air handler in a house can be a real challenge. Many times the equipment is surrounded by clothing or boxes where it is completely ignored. Filters are many times completely clogged or missing entirely. The frightful homeowner response of "Gee, is there supposed to be a filter in there?". Only when homeowners are challenged to change their roles of passive to active participant will they realize the value of preventative maintenance. We're not simply talking about changing filters. Even with filters, it isn't changing the filter that is as important as the type of filter used and the purpose of keeping filters clean. It's where the filter is located and how much dirt can actually bypass the filter, how much dirt has accumulated on the furnace or indoor coil, how to remove that dirt and how to keep the coils clean. The average home wastes anywhere from 25 to 40% of energy due to improper preventative maintenance. That figure can be higher if the system has been neglected for a long period of time. The "I'm too busy" excuse doesn't make sense when considering the amount of energy wasted can pay off even to the highest income levels.


So let's take a look at what an active serious homeowner energy conservationist would do to their home heating and air conditioning system. Assuming this is a home that was a recent purchase our homeowner would first look at the air filter. If there is no air filter you can automatically assume the coils and heat exchangers are clogged with dirt affecting heat transfer. If there is a standard fiberglass filter similar to those sold at home centers you can also be assured most of the dirt the filter is supposed to catch bypassed the filter and was attached to the coils and heat exchanger surfaces.


Coils need to be physically inspected if they are to be operating efficiently. In air handlers and furnaces with air conditioning coils there can be several coils. For example a gas furnace using pvc as venting materials will have condensing coils. These condensing coils look similar in appearance to air conditioning coils. If the air filtration is questionable or isn't a high media or pleated type of filter the assumption should be made the coils have dirt accumulation. In the case of the condensing coil this dirt will usually melt on to the surface of the coil and will be difficult if not impossible to remove. Operating the gas furnace and placing a thermometer on the outlet of the pvc plastic discharge can give a good indication of the performance of the furnace and the condensing coil. If the temperature of the flue gas is 120 degrees or more you can be assured the furnace has a problem and is not operating at the efficiency levels to which it was designed. Again back to the original suggestion of checking the condensing coil visually for dirt accumulation. This will involve removing ducting and looking at the air entering side of the coil. indoor air conditioning coils must also be inspected in the same manner form the entering air side of the coil. Since the vast majority of air conditioning coils are of the A type design, a visual inspection hole must be made to inspect the air entering side of the coil. An inspection mirror and flashlight will allow the entry side of coil to be inspected. If the wrapper on the coil was installed by the installing technician rather than a cased coil, it may be easier to remove and inspect. However the sheet metal is going to be attached to the connecting ducting and requires removal which may be difficult. Therefore an entry hole for inspection may be the most expedient method of checking the coil surface. Asking an installer or making the visual inspection access during original installation is easy and can be done without additional cost or inconvenience.  Inspection access for gas furnaces before the condensing coil can also be easily accomplished but will most likely met with resistance from the installing technician as it is a highly unusual request.

The most accurate method of examining a coil is to shine a light from the entering side to the leaving side and visually inspect for dirt accumulation that exists between the fins of the coil and builds up on the copper tubing. Depending on the thickness of the coil and the spacing of the fins dirt accumulation can vary. Some coils will build up solely on the entering face of a coil while other accumulate in between the fins then later blocking the face of the coil. In any event he coil must be inspected thoroughly using lighting between the fins from one side to the other.

Heat Exchangers

In addition to inspecting coils and heat exchangers on the indoor unit the outdoor coils must also be inspected. It is very possible and happens quite frequently that a coil shows no dirt accumulation on the entering surface but when a light is shining through the coil will reveal substantial dirt accumulation. Outdoor coils should be cleaned regularly with a garden hose. Make certain the electrical power is first disconnected and the motor is protected form water entering. After cleaning allow the system to dry for 24 hours before restarting. In an outdoor unit that hasn't been cleaned or excessive dirt has built up use a pressure washer to properly clean the coils.

Cleaning of coils can be accomplished with chemicals and high pressure water. Chemicals used for cleaning coils will vary depending on the type of coil. Indoor coils use milder cleaning agents while outside coils use very strong cleaning agents which can be dangerous and toxic. High pressure sprayers are great for producing cleaning results when accompanied by cleaning agents. Care needs to be taken to make certain the high pressure does not bend the aluminum  fins over and consequently reducing air flow and heat transfer.

Also coil fins must be checked for straightness and alignment. Fins can be straightened and aligned with a sharp knife if severely bent and then a fin comb. A fin comb is a plastic specialty comb used to realign the aluminum fins of coils. Fin combs can come at a specific number of fins per inch spacing. Universal fin combs have various fin combination head spacing. If you don't have a fin comb the process can also be accomplished successfully with a knife and individually aligning the fins to their correct position. Bent fins like dirt reduce heat transfer and waste energy as well as cause destruction to furnaces and air conditioners.

In addition to affecting heat transfer dirt accumulation in a duct system can also breed allergens and all types of creatures including dust mites and mold. A professional cleaning of the duct system may be required if there is evidence of substantial dirt accumulation on the coils.


To avoid dirt accumulation in your HVAC system look at the filter you intend to use. Put the filter up to the light. If you see gaps typical of those found in fiberglass filters sold in home centers realize how much dirt will bypass the filter and accumulate within the system after several years of use. If you can see directly through the filter don't waste time and money purchasing and installing it. 3M types of pleated filters which provide a solid filtration barrier are essential. The best solution is a high media filter which is four or five inches thick placed before the entering side of the furnace or air handler will provide excellent filtration for months at a time before it needs to be replaced. Or using pleated filters in conjunction with return air filter grills stopping dirt form entering the duct system completely. If the cost of a pleated filter seems too expensive in comparison to the cheap fiberglass filters all you have to do is think of the energy losses that will occur with the cheaper filters. Most fiberglass filters are great for catching large flies and rodents. Although somewhat better than no filter the purpose of the filter is to keep the equipment clean and energy efficient. Fiberglass filters do not accomplish this task. Most homeowners believe air filters are for cleaning up the indoor air environment. Nothing could be further from the truth as filters protect the HVAC equipment and effectively keep the system operating at maximum efficiency. Why aren't electronic filters recommended? After 40 years in manufacture electronic air filters continue to have a high rate of failure and it is difficult to check their proper operation. When they fail electronic air cleaners give no warning and will cause system components to accumulate with dirt and decrease efficiency before the problem is discovered.


Another important function of preventative maintenance is to inspect duct systems for leakage and proper insulation.Ducting exposed to unconditioned spaces such as attics and crawl spaces need to be properly insulated with at least an R-6 insulation. Further most sheet metal duct systems leak at least 25 cents of every energy dollar.Those duct seams and joints need to be sealed with rated duct mastic, UL approved aluminum duct tape or high temperature silicone caulking. Do not seal ducts with duct tape such as you find at building centers. Unless the duct tape is Ul rated for HVAC systems the glues in duct tape will not with stand the various temperature differences and soon fail. Remember that ducts whether they are return or supply ducts need to be sealed and insulated equally. For many years it was ignorantly said only supply ducts need to be sealed and insulated. Return ducts are equally important in your goal t achieve energy efficiency. Also not he ducting that exists after

the air filter needs to be without leaks as any air that is pulled into the duct system will be unfiltered and cause dirt accumulation of heat exchangers.

Insulation on ducts may fail due to moisture build up or the failure of duct tapes. Once insulation becomes wet or damp it losses it's insulating capabilities. Duct tape around duct joints will also fail after several years as most tape is not rated to withstand the pressure and temperature demands of HVAC systems. Insulate ducts without insulation or deteriorating insulation making certain to seal the joints first.


Condensate and Traps

A most overlooked item in preventative maintenance is the condensate line and trap. Traps are now being utilized more because of condensing furnaces which requires use of traps in winter in addition to air conditioning during the summer. Many times when traps are installed there is no access union. However this is a quick repair. Cut out the existing trap if no access unions are available. Take the trap and run hot water through it to break up and remove dirt and accumulated debris. Traps should always be installed with nothing less than 3/4" pvc. Copper and steel pipe traps become corrosive and block the flow of debris. For this reason it is best to use pvc plastic. If access to the trap is difficult use pressurized air and hot water to blow the trap clean. However the best method is to have an easily removable trap that can be readily cleaned once per year for systems with air conditioning only or twice per year for systems with condensing furnaces and air conditioning.

If the air handler or furnace is located above ceiling areas where a blocked trap and the resultant damage and destruction from the condensate would be costly, install an alarm such as a wet switch. In horizontal applications there should always be a condensate pan which works as a secondary protection. Place the alarm in the pan or there are also alarms which can be placed directly in the condensate trap. The alarm should also be wired to the air conditioning to prevent operation if water is detected preventing destruction. We do caution you however in wiring gas furnaces to alarms. If water is detected the alarm will shut off the heating and if nobody's home or away on vacation the resultant shut off of the furnace could potentially cause water pipes freeze and burst causing more than minor destruction. 

Refrigeration Lines and Charge

Refrigeration tubing or line sets that are used to connect air conditioning or heat pumps require insulation on the larger suction line tubing. This insulation may fail after several years and needs to be replaced.

As you are trying to keep your HVAC system up to maximum performance levels have an HVAC professional check and adjust the refrigerant charge. More than 50% of air conditioning and heat pump systems are under charged causing significant losses in performance and excessive energy consumption. Simply by having your HVAC system charge adjusted to maximum performance can reduce energy consumption by 25 to 60% on average. Adding refrigerant charge to any system on a regular basis without finding the source of the leak and correcting it not only causes capacity losses but wastes energy and ultimately results in premature equipment failure. If the service company you're using doesn't bother or can't find the leak, get another company that cares. Leaks almost always occur at joints either in the interconnecting lineset or in the unit itself. The basic method of using a soap detergent mixed with 1.5 parts of water or with sufficient surface tension and an acid brush will effectively find 99% of all leaks. Sometimes leaks will occur in the center of coils or tubing. When numerous leaks begin to plague a system they can be very expensive to locate and repair. A cancerous condition can occur within the system caused by acidic oil which will effectively eat away at the copper tubing. Systems affected by severe problems of acidic build up and deterioration can either be treated with additives or replacement of the system. Some systems become so plagued with acid that electrolysis begins to leach copper from the tubing and copper plate the compressor. Also anytime the refrigerant system is worked on and exposed to atmospheric conditions a new filter drier must be installed as a preventative measure. The filter drier used in burn outs or acidic conditions as described will assist at neutralizing oil and removing moisture from the system. Refrigeration systems are extremely sensitive to moisture, dirt and acid. These items are classified as contaminants and can quickly destroy any refrigeration system.

Chimneys and Venting

If your present heating system uses a chimney it is imperative the chimney is inspected every year. If there is no liner in the chimney one should be installed. If your chimney has continuous debris accumulating at the base of the chimney the chimney needs to be cleaned, lined or abandoned. Due to the high prices of natural gas it is always recommended to have a high efficiency gas furnace installed which eliminates the need for a chimney. Beginning in 2006 the Department of Energy will be offering tax credits for gas heating systems that are installed with 95% efficiency or greater. Also further rebates for ultra efficiency air conditioners, heat pumps and variable speed motor options are also available allowing for up to a $300 tax credit. If your existing furnace or boiler uses a chimney there are substantial energy savings and safety reasons to abandon the use of a heating system requiring a chimney. If you have no chimney or your present chimney is in total disrepair and you present system requires a chimney consider installing a side wall vent kit as shown in the illustration.


Other Areas

The following items are generally not considered normal preventative maintenance but should be considered as part of any preventative maintenance program. The goal is to provide safe energy efficient operation and maximize equipment longevity. Any and all items that enhance the performance and achieve these goals need to be considered.

Outdoor units are now required to have GFI Ground Fault Breakers with electrical outlets in most areas. As mentioned previously cleaning of these coils on an annual basis should be part of every routine preventative maintenance program. Having safe electrical power to your outdoor equipment should also be considered part of this procedure.

In addition upgrade the present thermostat to the more hi tech thermostats. Newer thermostats do much more than control the temperature and are part of energy efficiency and energy management. Utilizing total control of the HVAC by providing efficient operation with reminders for changing filters and monitoring the hours of operation of the equipment provide useful information for service and efficiency. In addition the new hi tech thermostats change temperatures during unoccupied or nighttime operation and reestablish temperatures efficiently which are important for reducing energy consumption and reducing wear and tear.

Some service technicians are really into preventative maintenance while most are not. Knowing the difference can make substantial improvements to the energy efficiency of your heating and air conditioning system. Realize most homeowners can save 25 to 40% of their energy consumption by doing a thorough preventative maintenance program. After you have maximized the basic efficiency of your heating and air conditioning system, you can then effectively consider replacement of the equipment to further increase your energy savings. But realize there are no fancy gadgets or gizmos that can take the place of basic preventative maintenance.

When is it time to replace the HVAC equipment? Whenever the replacement of the system will provide cost effective returns on your investment or repairs or total system failure is close at hand. The last thing you want is to deal with an unexpected replacement. There's no time to shop or consider a do it yourself installation if your system fails in the dead of winter or when the hottest days of summer are upon you. Here are some certain times when it is best to replace your present system. If the system is ten years or older. If the heating efficiency is less than 90%. If the Seer efficiency of the cooling or heat pump system is 8.0 or less. If the system has had repeated service calls in the past two years. If the replacement system can reduce your energy consumption by 35% or more.

For more information on preventative maintenance visit our library section. For questions call DESCO Energy toll free at 877-265-9764 or email info@descoenergy.com       

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