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AC Control Air conditioning is a family owned and operated company, proudly services all of your air conditioning, heating, and air quality needs. We service all of inland Empire Riverside, corona, chino, Chino hills, Pomona, Ontario, Eastvale, Mira Loma, Over the last 20 years, AC Comfort Air & Heating has built a spotless reputation for comfort, value and dependability.

Air Conditioning and Heating Repair

At AC Control Heating we don’t charge for a service call whiting 20 miles

We will come to your home and give you a free diagnostic and offer you several options at reasonable prices and we are confident that with our reasonable prices you be happy. And be sure that we will never try to sell you something you don’t need. . We guarantee that you will receive the best customer service experience possible. We do service all brands. Carrier, Bryant Goodman, Payne, Trane, Tempstar, Day&Night , Amana, Rheem, Ruud, York, Colman, American standard, Lennox, Guardian, Luxaire, Mitsubish, Janitrol, Heil, Ducane, Air flo,


All HVAC contractors can do installations. But ,there are very few that can do Quality Installations

Our professional cooling and heating installations are Quality Installations with competitive prices you are sure to get the quality of work you deserve at the price you can afford. Your satisfaction is guaranteed. We put it on writing that if you are not satisfied wit our work you won’t have to pay for anything. It is just that simple you are not happy we will take out our equipment and you don’t pay We stand behind our work because all of our technicians and installers are certified and trained. We are fully licensed, bonded, and insured which means no worries for you, so call today or schedule an appointment online and one of our HVAC professionals will be glad to assist you.

Quality of Air Conditioning System Installations

The first question that I hear is what brand do you Install? And the answer is any.

But to be honest any brand can be good or bad… the number one thing about an AC installation is the Quality of installation and the quality of components use in the installation.

These are the key ingredients for a good installation that will be performing at its highest efficiency

  1. Quality of Design (25%)
  2. Quality of equipment (5%)
  3. Quality of Components (8%)
  4. Quality of installation (52%)
  5. Quality of Commissioning (10%)

So here you have it…the best brand available install poorly won’t perform as design

These are the key ingredients for a long lasting of you equipment 20-30 years

  1. Quality of installation (50%)
  2. Quality of Equipment (7%)
  3. Quality of Maintenance (33%)
  4. Quality of Service (10%)

We here pride ourselves in performing the best installation possible using the best components (materials) available and testing the equipment to perform as designed. We also have maintenance programs available to care for your equipment and our knowable stuff will recommend a program to fit your needs.

Duct Design is the very important on a quality installation to move the right amount of air to all rooms of the house Theirs is more to designing a heating, Cooling, or ventilation System then just placing ducts on the roof or in a attic. if the duct sizes have not been calculated to determinate the correct airflow to each room, is not a matter of if, but only when, system and/or air balance problems will surface. Proper Airflow and charging of a new or existing HVAC system, are the two most dynamic process we directly control during installation or servicing of the two, proper airflow is the most critical in terms of overall system capacity, energy efficiency, and system reliability because if the airflow is not correct, it is impossible to properly charge the AC system. There is other very important part of a quality Installation, there are the return grilles and supply grilles, the type, size, location, and number of grilles should be given equal considerations.


The function of the compressor is to draw in low pressure & temperature vapor refrigerant, compress it and discharge high pressure & temperature vapor refrigerant. The compressor has an electric motor and mechanical compression system inside the shell, or casing. Both if which are cooled by the relatively cool incoming refrigerant. The compressor can only pump refrigerant vapor. If liquid refrigerant is allowed to enter the compressor it will start to destroy immediately.

The number one failure of compressors is poor maintenance of the HVAC System. This is very common the AC system will star to loose refrigerant and the compressor wont gets its normal cooling and the motor will star to over heat and burn. The second most common cause of compressor failure is restricted airflow this is normally caused by a dirty air filter that will restrict the airflow going to the evaporator coil and liquid refrigerant will migrate to the compressor and will destroy the compressor valves.

There are three major Types of residential and light commercial compressors in the industry. THE ROTARY COMPRESSOR, THE RECIPROCATING COMPRESSOR, AND THE SCROLL COPRESSOR,

The rotary compressor is a positive displacement compressor that uses either a rolling piston, rotary vane or screw type mechanical system to compress the refrigerant is used primary in a small HVAC systems

The reciprocating compressor it a positive displacement compressor that uses the piston, or piston, driven by a crankshaft to compress the refrigerant vapor, is is primary use medium to large HVAC units

The Scroll compressor is positive displacement compressor that uses one spiral to orbit around a second stationary spiral to compress the refrigerant vapor.

It is primary used in medium to large HVAC units


Getting the Most From Your HVAC Systems

Does your HVAC system operate as efficiently as it could? Is your HVAC system compliant with health, safety and environmental regulations? Do you face continual maintenance issues with your HVAC system? In other words: is your HVAC system in good shape, or is it costing you a bundle for no good reason?

With any facility assessment, one of the first areas to check out is the HVAC. You need to determine how much time you have left on the system’s lifecycle. If your HVAC system is extremely old, it could be sucking up energy and wasting your money. It could also be causing indoor air quality issues that lead to problems like Sick Building Syndrome. Or, your old HVAC could be racking up big maintenance bills. If so, then you need to know what’s wrong so you can fix it.

Energy use is a good starting point because the opportunity for cost savings is significant. Lighting tops the list of the potential savings, but HVAC runs a close second. Did you know high-tech HVAC systems could save 30 percent to 40 percent on energy costs? That’s nothing to sneeze at. The return on investment on HVAC upgrades ranges from one to five years, depending on the system’s level of use. That’s well worth the money, considering HVAC systems can last 10 or more years, depending on usage and climate conditions.

Interestingly, the design of an HVAC system has major impacts on productivity and energy savings. If you don’t have good controls on your HVAC, then you are wasting tons of money. It could be that you are simultaneously heating and cooling different parts of the building at the same time. That’s counterproductive and puts a lot of strain on the HVAC.

According to the California Energy Commission, an HVAC system should be properly sized to provide correct air flow, and meet room-by-room calculated heating and cooling loads. It should also be installed so that the static air pressure drop across the handler is within manufacturer and design specifications to have the capacity to meet the calculated loads.

Beyond the proper design and installation, experts encourage regular HVAC maintenance to ensure the best operation. Air filters should be changed each month, for example, and HVACs also need to be properly charged with refrigerant and have proper burner operation and draft.

If you do not have an HVAC maintenance crew on site, be sure to contract with a local air conditioning maintenance company to do regular check ups. This will extend the life of your HVAC and save money on heating and cooling costs.

This article is brought to you by Jon Levine for Capitol Supply, Inc. Capitol Supply offers over 1 million products for commercial, consumer, government and GSA offices from office products, school supplies, cleaning supplies, Georgia Pacific products, consumer electronics; dorm, home and office furniture; hardware supply, car parts, HVAC and government, commercial or consumer appliances.

Have Your HVAC System Serviced Annually

Almost every manufacturer of furnaces and HVAC systems recommend that you have the unit inspected and serviced at yearly intervals. However, many people overlook this necessity and forego service for longer periods of time, either due to cost issues or forgetfulness. Skipping annual service on you HVAC system could lead to spending more money in energy bills, not to mention put the health and safety of you and your family at risk. A licensed HVAC service technician will ensure your HVAC unit is operating properly and at maximum efficiency – which will save you money and heartache in the long run.

If you have an oil or natural gas furnace, your HVAC system burns fossil fuel. The burning of these fossil fuels can result in a deadly byproduct – Carbon Monoxide. An HVAC service technician will make certain that there is no risk of carbon monoxide poisoning coming from your furnace. Even small leaks can be hazardous, so an annual service inspection to check for the deadly poisonous gas is highly recommended.

Also, furnaces that use oil or natural gas are also at a higher risk of fire because these fuels are highly flammable. An HVAC specialist will ensure your unit is operating properly and is clean of dirt, dust, debris and other materials that can easily catch fire.

One of the most advantageous benefits of having your HVAC system annually serviced is maximizing its efficiency. Home heating fuel is very expensive, so making sure your HVAC system is burning it at an efficient rate is directly related to the amount of your energy bills. A professional HVAC service technician can adjust your furnace to ensure it is operating at its highest efficiency. Inspections and “tune ups” will result in less fuel consumption and lower bills.

Having your HVAC system serviced on an annual basis is a great way to have preventative maintenance done. It is recommended that annual service be performed before the winter months to ensure the furnace will work properly throughout the cold season. Often times, an HVAC contractor will notice potential problems before they begin and offer solutions for repair or replacement of parts. This can be extremely beneficial to a homeowner because they will not have to go through the struggle of having their furnace break down in the dead of winter, leaving their family with no heat for days or weeks until it can be repaired.

The advantages of having a furnace inspected and serviced by a professional HVAC technician are tremendous. You’ll save money on your fuel costs and energy bills, and have peace of mind that your furnace will run properly on even the coldest of winter days. Your be sure your HVAC system is operating safely and at the highest efficiency by hiring a professional HVAC engineer to inspect and service your furnace on a yearly basis.

The HVAC specialists offer maintenance, repair, and new system installation for homeowners with trusted service they can depend on. Arundel offers the latest in energy-efficient models to keep your home comfortable while lowering your monthly energy bills.

Choosing the Right HVAC System For Your Project

HVAC stands for heating, ventilation, and air conditioning. These systems provide the indoor climate control for both residential and commercial buildings. When it comes tothis, one size does not fit all. As a matter of fact HVAC systems can be quite complex. Determining the right type of system for your home or building is extremely important for the system to heat and cool effectively and to be energy efficient as well.

HVAC systems come in many types and applications. They are classified as either central or local. The central air conditioning and heating system provides the necessary heating and cooling and ventilation from a central location in the building such as from a boiler or furnace. It works by circulating heated water or steam through piping or ductwork to achieve heating and cooling.

Central air conditioning units use a compressor and a condenser unit that uses a refrigerant or coolant such as Freon. The refrigerant is circulated through copper tubing. The refrigerant absorbs the heat, turns to vapor, travels to the compressor, and moves to the outdoor coil where the heat is forced out. Then the refrigerant passes through a device where it is converted to a low pressure, low temperature liquid and returned to the indoor coil. The cool air is then circulated through the ductwork to provide cooling for the structure.

Local HVAC systems are devices that provide heating and cooling to immediate areas or rooms. They do not circulate throughout entire structures. Local HVAC systems may include wood or pellet stoves, window air conditioners, and space heaters. Electric baseboards are also considered to be local HVAC systems if the unit is installed into a single area.

Determining which HVAC system is right for you and your needs should be determined by an HVAC professional in order for you to get the maximum benefits from the system. A qualified and certified HVAC contractor will determine the type unit that is best for you and will install the unit in the proper place so that it will meet your cooling and heating requirements.

Modern HVAC Systems

Heating, Ventilating and Air Conditioning (HVAC) systems help to regulate the climate and maintain the indoor air quality of homes and commercial buildings. While sophisticated and reliable HVAC systems have become common in daily modern life, they have not always been so widespread. However, the principles that these systems operate on have long been known to scientists and engineers. Even though advances in the reliability and cost effectiveness of HVAC systems continue to improve, we enjoy very mature technology from this industry segment today.

The modern air conditioning system has been in continual development since its invention in 1902 by Willis Haviland Carrier. The system that Carrier invented was used in a printing plant to regulate the temperature and humidity of the air, thus causing the process used there to operate more consistently and reliably. Thereafter, the demand for commercial air conditioning exploded and Carrier formed his own company. It was not until the 1950s, however, that residential air conditioning became wide spread.

Because many early air conditioning systems used toxic and flammable gases to produce cooling, their utility was limited, so in 1228, Thomas Midgley, Jr invented the first chlorofluorocarbons (CFC) for use in refrigeration systems. This became popularly known by the DuPont brand name Freon, and it greatly enhanced the safety and reliability of refrigeration and air conditioning systems. However, in the 1970s scientific studies were starting to show that the release of CFCs into the air was depleting ozone levels in the stratosphere, resulting in higher incidence of harmful solar ultraviolet radiation reaching the earth’s surface. Because of government action, the use of all CFCs and related chemicals have been restricted and are expected to be completely phased out by 2010. Newer non-ozone-depleting refrigerants have been developed and are being phased into HVAC systems currently available on the market.

Our understanding of properly engineered HVAC systems was further advanced after the World Health Organization (WHO) issued a report in 1984 on Sick Building Syndrome (SBS). SBS was found to result from poor indoor air quality, and several solutions have since been developed to prevent this condition from developing. Proper maintenance guidelines for HVAC systems can help to prevent SBS; additionally, the use of an air-to-air heat exchanger can be employed to increase the amount of fresh outdoor air that is brought into a building without sacrificing energy efficiency. The current recommendation from American Society of Heating, Refrigeration & Air Conditioning Engineers is to provide 8.4 exchanges of air within a 24-hour period.

With increasing costs for energy a primary focus, continued research today is improving the energy economy of HVAC systems. In an effort to reduce the ecological impact of new and existing building design, the U.S. Green Building Council promotes adherence to a set of guidelines known as Leadership in Energy and Environmental Design (LEEDS). Energy efficient HVAC systems are an important component to the success of the implementation of LEEDS standards.

Today we enjoy safe, efficient, and reliable HVAC technology. As an essential part of our daily lives, these systems will continue to be adapted to our changing needs by today’s graduating scientists and engineers.

The switch by air-conditioner manufacturers to a more environmentally friendly refrigerant is complete. Manufacturers of central air conditioners have held prices steady, but installation costs are up because of the switch. And the federal government isn’t helping as much with the purchase as it did 2 years ago.

A funny thing happened on the way to promoting the purchase of energy-efficient air conditioners: The federal tax credits that were intended to heat up consumers’ interest in high-efficiency central air conditioners 2 years ago dried up.

The good news is that prices are about what they were in 2009, although the new standard for refrigerants, R-410A, has led to an increase in installation costs. Meanwhile, developments in the past 2 years have focused on tweaks to help central air conditioners to run more efficiently and on technology that helps to diagnose problems. The federal tax credit that was part of the American Recovery and Reinvestment Act of 2009 isn’t gone, but it’s only a shadow of its former self.

WHAT IS A SEER (Seasonal Energy Efficiency Ratio)

For air conditioners, this metric is called a SEER rating, Seasonal Energy Efficiency Ratio. Higher the SEER ratings mean greater efficiency.

As of January 2006, the federal government mandates that all new central air conditioning equipment be at least 13 SEER, but there is equipment available rated as high as 18 and even 23 SEER.

AC Doctor urges you to install an air conditioning system that is at least 16 SEER, especially if you live in the Sunbelt where air conditioning systems run most often. Use the cooling Calculator to see the impact on your wallet and your environmental footprint that is higher SEER Air Conditioning can have for you.

That incentive gave to consumers a tax credit of 30 percent of the installed price, up to a maximum of $1,500, for a new central air conditioner that had a seasonal energy-efficiency rating (SEER) of at least 16. The program was extended through 2011, although the maximum tax credit has been reduced to a flat $300. You also can get the $300 tax credit through the end of the year if you install a package system [cooling and heating], in which all of the cooling components are in one cabinet, the cooling function has a 14 SEER and the heating function has an energy-efficiency ratio [EER]

Previously, you could recoup most of the typical difference in price between a 13-SEER air conditioner (the minimum efficiency standard) and a more efficient 16-SEER model. It was a good deal. Is it still worth your hard-earned dollars to buy a higher efficiency unit? Contractors, unsurprisingly, say yes, but beyond the obvious—the fact that they stand to make more money installing the pricier 16-SEER unit—the reasons are compelling.

The annual per-ton cost of a 13-SEER central air conditioner would be about $270 per year, so a 2-ton model would cost $540 per year to operate. A 16-SEER system would cost $219 per ton or $438 per year to operate a 2-ton unit—a savings of $102 per year. (Figures will vary depending on geographic area, utility costs and use patterns.) Adding in the tax credit would mean that you could pay off the difference in the purchase price of the central air conditioner—roughly $1,000—in 7 to 8 years, which is well within the typical lifetime of a central air conditioner. Of course, as electric rates rise, savings would increase as well.

COOL INNOVATIONS. The big development in the efficiency of central air conditioners that seemed imminent 2 years ago hasn’t happened. Nordyne remains the only manufacturer that uses inverter technology, which allows a system’s motor, compressor and fan to run at variable speeds. That means that the air conditioner uses only the electricity that’s required to achieve cooling demands and results in super-efficient cooling (24.5 SEER, compared with a non-inverter industry high of 21 SEER). Although other major manufacturers told Consumers Digest 2 years ago that they were testing inverter models, none has produced such a model, and they wouldn’t even tell us whether they still were pursuing inverter technology.

Instead, manufacturers have made only tweaks to their products. For example, Trane dialed up its thermostat technology a notch. The company applied Internet connectivity to its central air conditioners. Trane’s ComfortLink II thermostat—when it’s coupled with a telephone-access module, which is a control box that’s on the air conditioner and uses its own Internet address—allows you to adjust temperature settings by using your computer or smartphone. You’ll pay about $750 to cover the installed cost of the thermostat, router and access module, plus a yearly $99 fee to Trane. This technology works only on Trane’s premium XL20i and XL16i air conditioners, and you also must have a Trane thermostat that has that communicating technology. Other manufacturers are mum about embracing Internet connectivity, but given that such connectivity is being pursued by at least three appliance manufacturers, we wouldn’t be surprised if more air-conditioner-makers quickly jump in. For now, the price seems a bit steep for the convenience.

Not as high-tech but still noteworthy: More major manufacturers are using all-aluminum evaporator coils, which are designed to combat corrosion. Coils typically have been made of copper, but in high-humidity regions of the country, such as those that are near to large bodies of water, copper coils can corrode within a few years or, in extreme cases, even a matter of months. A new coil will cost you at least $300—the price varies by model size and manufacturer—and that’s not counting the labor costs to install it.

Goodman, Nordyne and Trane have, or are planning to have, all-aluminum coils in their central air conditioners. Goodman tells us that its all-aluminum indoor evaporator coils will be used in all of its air conditioners by year-end, and—better yet—that that will happen without increasing the cost to distributors (and thus, presumably, to consumers). Nordyne introduced all-aluminum outdoor evaporator coils in its 13-SEER air conditioners in 2010 and will expand that to its 14-SEER and 16-SEER units this year. All-aluminum indoor coils are forthcoming, although Nordyne declined to say when those would arrive. Prices to Nordyne distributors will not increase, the company says.

R YOU LISTENING? The deadline for all new air conditioners (central and room units) to use the environmentally friendly R-410A refrigerant has passed, and manufacturers with whom we spoke say R-410A will be the refrigerant of choice for the foreseeable future. Although central-air-conditioner manufacturers have eased in the use of R-410A refrigerant over the past few years to keep the prices of their products steady, that isn’t the case when it comes to the installation costs.

Heating and cooling contractors say you should expect to pay as much as 15 percent more to have an R-410A central air conditioner installed than you paid to install an old R-22 model. Contractors say those additional costs typically are for replacing refrigerant lines to handle the higher pressure R-410A and evacuating R-22 out of the old systems.

Air Conditioning Diagnosis, & Repair Guide

  • How to inspect, diagnose, & repair central air conditioning systems and heat pumps: A/C repair, lost cooling, insufficient cooling.
  • What are the basic air conditioning components?
  • Determining air conditioning cooling capacity & energy efficiency
  • Troubleshooting air conditioning compressor problems
  • Diagnosing air conditioning air handler problems
  • Air conditioning condensate problems
  • Duct system inspections, defects, repairs
  • Cleaning air conditioning equipment & fixing leaking A/C refrigerants
  • Questions & answers about how to diagnose and repair air conditioning and heat pump systems.

Here is a simple explanation of how an air conditioning system works, with enough detail so that it isn't simply magic (the schematic of an air conditioner shown at left is compliments of Carson Dunlop) A detailed list and photos of air conditioner components can be seen at AIR CONDITIONER COMPONENT PARTS.

  • A air conditioning or heat pump compressor which compresses low pressure refrigerant gas into a high pressure, high temperature gas. Usually the compressor is in the outdoor portion of an air conditioning or heat pump system. The compressor is basically a high pressure pump driven by an electric motor. The air conditioning compressor is usually packaged in the outdoor compressor/condenser unit illustrated by our page top drawing. See COMPRESSOR CONDENSER, and see REFRIGERANTS & PIPING
  • A condenser or condensing unit: typically a condensing coil inside which high temperature high pressure refrigerant gas flows, and over which a fan blows air to cool the refrigerant gas back to a liquid state (thus transferring heat from the refrigerant gas to the air being blown by the fan). The condenser unit is basically a coil of finned tubing and a fan to blow air across the coil. Usually the condenser unit is in the outdoor portion of an air conditioning system, often packaged along with the compressor motor discussed above. See COMPRESSOR CONDENSER and see our page top sketch too. The change of state of the refrigerant, from hot high pressure gas to a liquid releases heat, including heat collected inside the building) to the outdoors.

  • A metering device which dispenses liquid refrigerant into an evaporator coil. The metering device may be simply a thin section of tubing (a capillary or "cap" tube) or it may be a bit more sophisticated thermostatic expansion valve (TEV) which includes a temperature sensing control that can open and shut the device against refrigerant flow. See THERMOSTATIC EXPANSION VALVES or see CAPILLARY TUBES.

  • An evaporator coil or cooling coil: typically the cooling coil is a section of finned tubing (it looks a lot like a car radiator) into which liquid refrigerant is metered and permitted to evaporate from liquid to gas state inside the coil. This state change of the refrigerant, from liquid to gas, absorbs heat, cooling the evaporator coil surface and thus cooling indoor air blown across the cooling coil. Usually the cooling coil is located inside the air handler. See AIR HANDLER / BLOWER UNITS and articles like DIRTY COOLING COIL. Evaporative cooling systems, or swamp coolers are discussed separately at EVAPORATIVE COOLING SYSTEMS.

  • An air handler and blower unit which provides a fan to blow building air across or through the evaporator coil. The air handler blower fan unit moves building air across the evaporator coil surface in order to condition building air by cooling it (and thus also by removing moisture from the cooled air). See AIR HANDLER / BLOWER UNITS and BLOWER FAN OPERATION & TESTING. 

  • A duct system which distributes conditioned air from the air handler in to the occupied space (supply ducts), and which takes air from the occupied space and returns it to the cooling system air handler. See DUCT SYSTEM
  • Heat Pump Systems use the same components we have described just above, with the addition of a reversing valve that in essence permits the system to run "backwards" in cold weather. So in air conditioning mode the heat pump is moving heat from inside the building to outdoors while in heating mode the heat pump is moving heat from outdoor air (or water in some designs) to the building interior. Because the ability of a heat pump to extract heat from outdoor air diminishes at low outdoor temperatures, heat pump systems in northern climates also include a backup or auxiliary heating system. Details of how heat pumps work, are inspected, diagnosed, and repaired begin at HEAT PUMPS.

  • Air conditioner controls and features, which include a room thermostat, electrical switches, fuses or circuit breakers, condensate handling system, and air filters. See OPERATING CONTROLS and AIR FILTERS for HVAC SYSTEMS

For photographs of these various air conditioning and heat pump parts, and for an explanation of where these air conditioning components are physically located, see A/C COMPONENTS which discusses Indoor A/C Components and Outdoor A/C Components

How to diagnose and fix an air conditioning system that is not working: list of diagnostic articles

Since the failure of an air conditioner to turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply, or even loss of air flow entirely can be due to a variety of problems with one or more components of an air conditioner or air conditioning system, after reviewing the lost air conditioner cooling diagnosis procedures described in this article, be sure to also review the diagnostic procedures at each of the individual air conditioning diagnosis and repair major topics listed just below. To return to our air conditioning and refrigeration home page go to AIR CONDITIONING & HEAT PUMP SYSTEMS.

Electrical problems on HVAC systems: Keep in mind that despite the depth of technical detail you will find here about all components of air conditioners and heat pumps, most service calls for non-working air conditioners or heat pumps turn up an electrical problem. So if your A/C system is just not working at all be sure to check all of our electrical and control setting suggestions first.

Mechanical problems on HVAC systems: tend to fall into these groups: refrigerant leaks, dirty condenser coil or unit, dirty evaporator or cooling coil, or burned out (or hard-starting) compressor motors. We have also seen a number of problems with fans and fan motors in both the compressor/condenser unit and in the air handler/blower fan unit. Some of those fan problems are mechanical - like a loose fan belt or blade.

If you've been thinking of upgrading your old central air-conditioning system, or installing central air in a house that has never had it, there's a lot to consider. Every manufacturer today offers a wide range of products, with one suited to nearly every situation. A few even make systems for houses that won't accommodate conventional ductwork. As you might expect, the two most important considerations are efficiency and cooling capacity, but there's more to it than buying the biggest, most efficient system you can afford. In fact, there's quite a bit more.

An Equipment Overview

Central air conditioning is, of necessity, a split system, with some components installed outdoors and others indoors. The heaviest, noisiest, heat-shedding components–the compressor and condenser coil–are installed outdoors, while the evaporator coil is installed indoors, usually in the form of an A-frame in the plenum of a forced-air furnace. In this case, the furnace's blower moves warm air over the coils and distributes the chilled air. The indoor and outdoor segments of the system are typically joined by two refrigeration lines and a low-voltage relay cable.

If a home is heated by some means other than forced air–baseboard or radiant floor heat, for example–the evaporator coil is typically mounted in a dedicated blower unit, which pushes the cooled air through conventional ductwork. Most blower units are installed in attics and crawlspaces and are connected to flexible, insulated ductwork, which is the easiest and least costly to install, especially in retrofit situations.

In houses built without ductwork, and where conventional ductwork would be too costly or too inefficient to install, a ductless central-air system is now possible. Ductless systems have long been popular in Europe and Asia, where building methods discourage ductwork, but are relatively new in the United States. The Carrier Corp. is one of several companies now making ductless systems for the U.S. market.

In these systems, a single outdoor compressor serves several, smaller evaporator coils located indoors, each in its own box and each with its own blower fan. These components are installed on exterior walls, usually on the upper half, where much of the heat accumulates. They're finished unobtrusively, but they can be quite large, often measuring 6 x 18 x 24 in. Condensation lines are routed outside, along with the refrigeration and electrical lines.

Ductless systems can also provide heat, either through resistance coils in the wall units or in heat-pump fashion. The advantages of ductless air over window air are that ductless systems move the noisiest components outdoors, they can provide heat, they distribute the air more evenly, and they don't block the better half of a window. Installation costs vary widely, but ductless systems can be more expensive than ducted systems. It's a sliding scale, with each home's variables–primary building material, number of rooms, house size and layout–coming into play. They're reliable and efficient, but they're not likely to replace ducted systems in the United States. They're considered problem solvers, with the problem being fairly rare.

How Conventional Systems Work

All heating and cooling technology grows from the law of thermal dynamics that says when hot and cold spaces are separated by a medium, the transfer through the medium will always be from hot to cold. Heat follows cold, whether the medium is human skin, an exterior wall or the metal surface of an evaporator coil. When warm, humid air is blown across the evaporator coil in your furnace, the heat in the air is drawn to and impinges on the cold metal surface of the coil's fin tubes. In the process, the moisture in the air condenses on the cold metal and drips into a pan below the coil, where it's drained off, thus lowering the humidity in the house.

It's a neat trick–a double trick–but it requires a repeatable cycle, over and over, every time the system's thermostat demands it. The evaporator coil needs to be constantly recooled and the heat it absorbs needs to be carried outdoors. This is accomplished with a liquid/gas refrigerant, which undergoes a pressure-induced state change. An outdoor compressor pressurizes the refrigerant, heating it to a gas state, then sends it through an adjacent condeser coil to be cooled and returned back to the evaporator coil. There it picks up household heat and carries it back to the compressor. When this cycle is repeated often enough, our homes become a lot more comfortable.

Understanding Energy Ratings

Air conditioners have always been prodigious users of electricity, but efficiencies have improved considerably in the past few years. Part of this improvement was federally mandated in 1990, through the culmination of the National Energy Conservation Policy Act of 1971. These regulations established minimum efficiency standards for heating and cooling equipment. As a result, nearly all models manufactured today are more efficient than those made just 10 or 15 years ago.

How are systems rated? Central air conditioners–the condenser units–are given a Seasonal Energy Efficiency Rating, or SEER. In simple terms, SEER is calculated by dividing the cooling capacity of a continuously operating air conditioner by the electrical input required to run it. The value is expressed in numbers. A SEER 10, for example, is now the lowest number allowed, and any number larger than that is accordingly more efficient and will cost less to operate. Along with the yellow Energy Guide tags attached to each appliance, these ratings give consumers a benchmark sense of where their choices fall on the energy-efficiency scale.

Most manufacturers now offer SEER 10, 11, 12 and 13 models, and some offer SEER 14. This gives you five separate efficiency options, with model numbers usually keyed to the SEER numbers, so they're easy to recognize. Lennox's Value 12 system, for example, is a SEER 12.

How Better Efficiencies Are Achieved

Like the auto industry in its quest for better mileage, cooling equipment manufacturers have combined some minor tweaking with some major re-engineering. Because the compressor is the biggest energy user, that's where they have focused much of their attention. The first step was to improve the internal components of standard, reciprocating compressors, so that less pressure–and therefore, energy–was lost to internal leaks. Another step was to increase the size of the condenser coil. With more fin-tube surface area, the returning refrigerant could be brought to the compressor with less heat, reducing the compressor's load.

These two steps yielded substantial savings, bringing condensers into federal compliance, but a complete retooling was needed to achieve significant improvements beyond this level. Part of the answer was a multispeed compressor. With two or more speeds, the system doesn't have to run full out on days when only mild cooling and dehumidification are needed. Full-speed use is still available for those really miserable days, but the compressor doesn't have to run wide open all the time. At low speed, the practical effect is that of a small compressor matched with an oversize condenser coil. The savings can be substantial and most manufacturers offer multispeed compressors in their lineups.

At the same time, engineers began testing a radically different kind of compressor–the scroll. Scroll compressors are so different that they practically defy description. But their mechanical advantage is clear. Because they generate much less friction, they experience much less wear. The final product is a compressor that is very efficient and lasts longer. Today, most companies offer some multispeed and some scroll compressors, though a few, like Ruud/Rheem, have gone to scroll compressors exclusively, as a statement of across-the-line quality. Any way you look at it, today's condenser units are better than those made just a few years ago.

The Freon Question

As a result of the Montreal Protocol, a conference that grew out of international concern over the ozone-depleting qualities of CFC chemicals, the EPA is mandating the gradual phaseout of Freon, or R22 refrigerant. The new, non-ozone-depleting replacement will be R4-10A. In fact, some manufacturers have switched to R4-10A in some models already. While this new refrigerant works just as well, it requires pressures up to 50% greater than Freon, so it can't be used in existing equipment. Interestingly, the higher operating pressure actually improves efficiency slightly. In any case, there's no practical way to convert existing equipment.

So where does this leave the tens of millions of us with Freon-based, R22 systems? The short answer is that the Freon phaseout is stretched so far into the future that nearly all of today's air conditioners will have been replaced by then. The EPA will require a substantial reduction by 2004, and all products containing R22 must stop production by 2010. The production of R22 itself must cease by 2020. For those few R22 units still in service at that time, recycled R22 will be available, though it will probably cost a small fortune.

Sizing For Capacity And Efficiency

Your heating, ventilation and air-conditioning (HVAC) contractor will size your equipment to meet the specific needs of your home. Factored into the equation will be the age of your house, the number and quality of its windows, how well it's insulated, how many stories it has, its size, and, of course, local energy rates. Contractors use industry sizing models, such as Model J, but most use them as a reference, modifying the results to accommodate their own years of experience. A 1500-sq.-ft. ranch-style home, for example, might normally require a 2 1/2-ton air conditioner, but if it's not well insulated, or if a good many windows have western exposure, or if the trees offer little direct shade, then a 3-ton unit might be more appropriate.

In any case, sizing is critical. If sized too small, the system will struggle, and even freeze over, on the warmest days. If sized too large, the system will cycle on and off too frequently, greatly reducing its ability to control humidity. It will also be less efficient. Keep in mind that efficiency ratings are measured at the factory, under conditions that may have little to do with your house. In any case, sizing is a job best left to seasoned professionals, and it's a good idea to seek out more than one opinion.

General Installation Costs

What do air conditioners cost, installed? Again, local prices will vary significantly, but in a typical Midwestern town, a nonunion shop might charge between $1200 and $1700 to replace an old, 3-ton air-conditioner with a new SEER 10 system. That's assuming a 1500-sq. ft. house, 20 years old, with ductwork in place. For a similar home that's new, with a gas furnace and equivalent air conditioning, the price would be $5000 to $7000, gas and electrical connections included.

The Price Vs. Efficiency Question

Of course, you'll always pay more for high-efficiency appliances, so the critical question is whether you'll save enough in the long haul to come out ahead. And that, unfortunately, requires a region-by-region, even a house-by-house, assessment. You'll need to work closely with your contractor to make an informed decision. Don't assume that high efficiency always pays. It may from a good-citizenship perspective, but real dollars should drive the rest of the equation. And don't forget to add the cost of interest on the money gained or lost.

All we can do here is provide some context. If, for example, your electricity costs you a low 6 cents per kilowatt-hour (kwh), and you live in a reasonably well-insulated home in the northern one-third of the nation, using your air conditioner 200 to 400 hours per year, a basic SEER 10 system is probably your best choice. There's little chance that you'd recover the several hundred extra dollars a SEER 11 or SEER 12 system would cost, spread over a 12- to 15-year projected service life. You may hope for longer service, and you'll probably get it, but don't count on it. A SEER 10 is also a reasonable choice if you plan to move in the next few years.

On the other hand, if you live in Yuma, Ariz., and run your air conditioner 2000 hours per year, then it makes sense to buy the most efficient model you can afford. The same might be true if you live on the Eastern Seaboard and pay 11 or 12 cents per kwh, or if you live in a house with stone or brick exterior walls, where insulation is simply not feasible. In these cases, high efficiency really is a good investment.

Prices vary by manufacturer and with local market pressures, but it's probably safe to say that each step up in efficiency will cost about $200. This may seem a paltry sum, and it is for many people, but when you consider that the equipment costs for an entire SEER 10 system might run $800 to $900, an increase of $200 to $800 is significant.

Quality And Warranties

Most manufacturers offer two quality levels for each SEER number. What you get in return is a better-made unit that runs three to six times quieter and lasts longer. A quieter-running unit can be a real plus if you–or your neighbors–are particularly annoyed by a loud air conditioner. You'll also get a better warranty: a 10-year compressor warranty instead of five, a 5-year warranty against leaks in the coils instead of one year. As with all step-up warranties, you're betting against yourself, which sometimes pays big dividends. If it paid more than about 40% of the time, however, the manufacturer couldn't afford to offer it.

Air Conditioner Maintenance

Whether you have an older air conditioner or a newer, high-efficiency system, maintenance is critical. Older units need all the help they can get and high-efficiency models won't deliver all that high-dollar efficiency without routine care. The primary culprit is dirt and debris, which clogs coils and taxes equipment, but even something as simple as an out-of-level condenser unit can reduce efficiency and burn bearings. Here, more than most places, maintenance pays. And all it takes is about an hour a season. In most cases, you won't even need to buy tools and materials.

Most of the work you'll be doing will be outdoors, on the condenser unit. To eliminate any chance of an electrical hazard, begin by opening the unit's electrical disconnect panel and pulling the disconnect block from its slot (Fig. 1). Most such panels come with a reversible on/off block. Just flip the block over, so that off reads correctly, and return it to its slot.

In order for the condenser fan to do its job, its louvered panel needs to be fairly open. The tradeoff is that plenty of leaves and debris get into the housing when the fan's not running. To remove the debris from this compartment, undo the screws at the top of the unit and tip the panel upward. Then, lift out any leaves, twigs and debris you find in the coil enclosure (Fig. 2).

To clean the outside of the coil, undo the screws from one of the side panels, or from all three sides, if the design of your air conditioner makes that more convenient. Then, use a soft-bristle paintbrush to sweep the fin tubes clean (Fig. 3). Always brush vertically, in line with the fins. Because the fan pulls air through these fins, you can expect to find a blanket of dust and lint clinging to the fins, which can really reduce efficiency.

The condenser coil's aluminum fins are paper thin and very delicate, enough so that you may find several areas where the fins are smashed together. Virtually anything can damage them. Of course, smashed fins won't remove much heat, so it's a good idea to straighten them whenever possible. For a minor crush, you can use a toothpick, but for professional results, nothing beats a fin-tube comb. They're only sold by HVAC suppliers, but they're inexpensive and will last a lifetime. We paid $11 for a 6-comb set, with each plastic comb sized to fit two fin spacings. Our kit, called Super Comb Model T-400, covers spacings from eight to 20 fins per inch and was made by Wagner Products Corp., 5190 N.W. 165 St., Miami, FL 33014. Be sure to match the tool to the spacing. Then carefully insert the teeth and comb through the damaged area (Fig. 4). You'll be impressed by the result.

After you've reinstalled all the panels, check the condenser unit for level. Condensers are often set on backfilled soil, which tends to drop like a rock, especially through the first few seasons. If the condenser has settled out of level, the strain can wear out bearings and reduce efficiency by as much as 10%. Check for level, in both directions (Fig. 5), and if needed, pry up one end of the support pad and add soil or gravel until the pad is level. Slate shims can also be used for minor adjustments.

And, finally, one of the most frequent air conditioner maintenance problems is a clogged condensate line. The culprit is a bacterial slime that grows in condensed water. To keep this line flowing freely, pour a 1:9 mixture of household bleach and water through the line every month or so during cooling season. Just pull the hose from its A-frame fitting and flush the line, all the way back to the floor drain

Basic Diagnostic Clues Indicating a Failed A/C or Heat Pump Compressor Motor

The compressor won't start, perhaps just hums, and the motor star/run capacitor(s) are ok or you've tried replacing that part

As soon as the compressor tries to start the circuit breaker trips or fuse blows. The compressor motor has burned out, is internally shorted or gounded. A service technician will use a VOM and typically will find low resistance (low Ohms) between one or more compressor terminals and ground.

A VOM connected to the compressor circuit indicates that no current is being drawn, but the condenser fan is running properly. 
Watch out: before assuming that the compressor motor is bad, when the unit won't start at all, check for a loose or disconnected electrical connection or a bad contactor relay. An overheated motor may also leave the compressor motor "off" due to a tripped internal overload switch or a switch that has simply failed. If this is the problem, the motor should start normally once the unit has cooled down. (Some readers describe spraying water on the condenser unit to speed cooling - (don't wet electrical switches & components.)

Basic Electrical Tests on Air Conditioner or Heat Pump Compressor Motors

When an air conditioning compressor has "burned out" by shorting of internal components - it will fail to start at all. This failure is detected by disconnecting all power and wiring from the unit and measuring resistance (ohms) between the motor start/common and run/common terminals.

Zero resistance: If there is zero resistance the winding is open or broken.

Infinite resistance: If you measure the resistance across a compressor winding and your meter's needle is stuck over at infinity, or "OL"/"OVER" on a digital meter, that would indicate the compressor winding is open (burned through). The same effect can be observed from simply connecting the meter to absolutely nothing. Typically if just one widing is "open" you'll see infinite resistance at one check point and in contrast (for the non-open windings) you will read zero resistance ("continuity") between the Common terminal and the Start or between the Common terminal and Run terminal.

Low resistance: If the resistance measured across the air conditioning compressor winding is too close to 0 ohms, it's shorted. The compressor should blow the fuse or trip the circuit breaker when power is turned back on. But watch out: we get field reports of equipment burn ups and even fires when the air conditioning circuit breaker for the compressor happens to be an old FPE Stab-Lok or Zinsco unit.

If there is resistance but not infinite resistance between the motor terminal and the motor casing, the motor has become shorted to ground internally and the unit needs to be replaced. If there is no resistance between the start and run terminals to common, but there is resistance between the start and run terminals, this means that the internal motor overload protection circuit is open. In this last case, allow the motor to cool and re-test it before replacing it. See REPLACING A COMPRESSOR.

For details about measuring RLA / FLA, and definitions of RLA, FLA, and LRA,

Other (Non-Electrial) Refrigeration Compressor Failure Modes

Watch out: for a mechanically frozen compressor: a compressor may pass all of these electrical tests and still require replacement. The tests above only test electrical connections and windings. An air conditioner or heat pump or refrigeration compressor that has jammed up mechanically internally will still refuse to start (perhaps will hum) when all of the electrical tests, contactor relay, start capacitor, etc. are tested as perfecliy fine.

A compressor with broken internal parts may also not be frozen, that is its internal electrical motor may start and run, but the compressor fails to produce any refrigerant pressure at its outlet side. In this case internal parts or valves in the unit have broken without jamming the motor itself. In this case, all of the electrical components and tests will look "OK".

A compressor with broken internal motor mounts may make a rattling or clanking sound and needs replacement. It will continue to run but could become shrapnel at any time.

A compressor with bad internal valves will continue to run but is inefficient and should be replaced. The symptom is very quick equalization of high and low side pressure as soon as the motor stops.

When to replace a sealed-unit air conditioning or heat pump compressor?

Burned up electric motor in the HVAC compressor

Some compressor motor failures are so apparent that there's no question: an electric motor burnout that draws high amps or is internally shorted, for example.

Abnormal HVAC compressor pressures

But what about a compressor motor that may be just "worn" ? An HVAC compressor should be able to pull at least 15" of vacuum against 100 psi head pressure or else it is inefficient. Of course to make this test you must be able to isolate the compressor from the rest of the cooling or heat pump system, so this test is not rapidly made in the field.

Bad HVAC compressor refrigerant valves

Bad air conditioner reed valves will be unable to pull pressure down on the low side of the system. A leaky discharge reed valve (on the compressor output side) pulls hot gases back into the compressor cylinder and recompresses them, causing abnormally high head pressures at the compressor motor. And as a result the compressor won't be able to move vapor.

In sum, HVAC compressors do fail and need replacement, but only when you have tested and ruled out the other 80% of the causes of common air conditioning, heat pump, or refrigeration problems (usually electrical in nature) do you go ahead and replace the compressor unit.

General advice: Electrical Tests to Check HVAC Blower Fan Motor or Outdoor Compressor Fan Motor Winding on Heating or Cooling Equipment or on Other Electrical Motors

Air Conditioner Compressor/Condenser Fan Not Working?

Details of compressor/condenser unit fan inspection, diagnosis, and repair are at A failed compressor/condenser fan can cause the air conditioning system to shut down due to an overheating compressor or excessive pressures developed inside the compressor. If your compressor/condenser unit does not include a safety override switch to perform this shutdown and if the condenser unit fan is not working, your compressor motor may be permanently damaged. At NOISES, COMPRESSOR CONDENSER we include some condenser fan noise problems are traced to the cooling fan motor, bearings, fan blades, obstructions, etc.

if your compressor/condenser unit motor is running but the fan itself is not blowing air, the system will not work and may be seriously damaged. The outdoor cooling fan or condenser unit fan is needed not only to cool high pressure, high temperature refrigerant in gas form so that it can condense back to liquid form.

That cooling step also cools down the compressor itself and keeps the compressor internal pressure from becoming too high. Most modern compressor / condenser units include an overpressure sensor that will shut the equipment down if compressor pressures become too high. Some older models and some modern economy air conditioner compressors may lack this function.

testing a blower fan motor winding: referring to the electrical diagram for your equipment, unplug electrical connectors at the fan motor. Measure the resistance between each lead wire with a multimeter or VOM. The multimeter should be set in the X1 range. For accuracy, don't measure when the fan motor is hot, allow it to cool off.

When the resistance between each lead wire are those listed in the specifications for your equipment the fan motor should be normal. Zero resistance or infinite resistance are indicators of a problem. More examples of checking wiring:

Common Causes of Burned Out Air Conditioner Compressors

  • Contamination of refrigerant, piping, or devices in the refrigeration system: contaminants, including air, moisture carried in by air, and dirt can enter the refrigeration system as contaminants due to a leak on the suction side or improper service procedures such as mis-handling of service port valves or opening the system for repairs without adequately drawing a vacuum and without proper use of filter/dryer canisters. Air in the system can also lead to refrigerant flooding discussed above.
  • Cooling problems - compressor motor overheats: a compressor motor that keeps on running when the compressor/condenser fan has failed or when air flow through the condensing coil has become blocked by debris or damage can cause abnormally high compressor head pressures and operating temperatures. If the condenser fan is running but airflow is impaired the system may continue to "run" but at reduced cooling capacity and shortened compressor life. We found a stack of nine A/C compressors improperly installed without adequate cooling air flow at a wealthy client's home in Pawling, NY. Compressor motors were being replaced every year or two because the owner installed a stockade fence to "hide the ugly equipment". A compressor may also run too hot due to too-high temperatures at the suction line and low-side of the compressor system. Under-charged refrigerant levels or lack of insulation on the suction line piping can cause these problems as might a TEV that is not quite flooding the system but is releasing refrigerant too fast through the cooling coil. [2]

  • Refrigerant Pressure problems - excessive high side pressure may be caused by a restriction or blockage such as in the condensing coil, refrigerant metering device, or even at the cooling coil. Excessive high side pressure causes hot compressor operation, lost cooling capacity, and ultimately damage.
  • Refrigerant flooding - sending liquid refrigerant into the compressor motor is a quick way to destroy its moving parts or valves. We discuss refrigerant flooding and six common causes of liquid refrigerant slugging the compressor at THERMOSTATIC EXPANSION VALVES, and aside from TEV (TXV in some literature) problems, a mistake like overcharging the system can lead to liquid refrigerant can end up in the compressor bottom where only refrigerant gas is expected - causing the same failure problems. Christopherson, [2]
  • Refrigeration oil lubricant - lost due to system leaks (most likely you'll know there has been a history of refrigerant leakage too); also refrigeration oil can travel in the refrigerant lines where it reaches a capillary tube or TEV , clogging it and causing abnormal system pressures that can damage the compressor. On commercial refrigeration systems that us a separate oil pump to deliver lubricant to the compressor motor, an oil pump failure also leads to compressor motor failure.
  • Electrical problems that can damage A/C or heat pump motors are cited by Christopherson, including improper voltage (hooking up to an incorrect voltage level supply (110V to 220V or 230V applied to a 208V motor), poor power quality delivered to the system such as at homes subject to significant fluctuations in actual voltage levels in the incoming mains, loss of voltage on one phase of a three-phase electrical hookup (more common on commercial than residential refrigeration equipment), and finally, unbalanced current across the individual phases of a three-phase electrical hookup. [2]

Worn out compressor internal parts - a compressor motor may fail due to mechanical wear, though in our OPINION and having seen some refrigeration compressor motors that ran for decades with no trouble, we think mechanical wear is likely to be traced to a refrigerant, lubrication, contamination, or perhaps mounting problem. See our contamination comments above.

How to Repair Central Air Conditioners

Central air conditioners have two separate components: the condenser and the evaporator. The condenser unit is usually located outside the house on a concrete slab. The evaporator coil is mounted in the plenum or main duct junction above the furnace.

Most central air conditioners are connected to a home's forced-air distribution system. Thus, the same motor, blower, and ductwork used for heating are used to distribute cool air from the air conditioning system. When a central air conditioner is operating, hot air inside the house flows to the furnace through the return-air duct. The hot air is moved by the blower across the cooled evaporator coil in the plenum and is then delivered through ducts to cool the house. When the air conditioner works but the house doesn't cool, the problem is probably in the distribution system.

                                                                     Central air conditioners are made up of two separate components: the condenser unit,

located outside the house on a concrete slab, and the evaporator coil above the furnace

Both the evaporator and the condenser are sealed. Therefore, a professional service person should be called for almost any maintenance other than routine cleaning. Central air conditioners should be professionally inspected and adjusted before the beginning of every cooling season. However, don't let your maintenance end with this annual checkup. While there aren't many repairs you can make yourself, there are specific maintenance procedures you can follow to keep your system operating at peak efficiency. Caution: Before doing any work on an air conditioning system, make sure the power to the system, both to the condenser and to the evaporator assembly, is turned off

Cleaning the Evaporator

The evaporator for the central air system is located directly above the furnace in the plenum. The evaporator may not be accessible, but if it is, you should clean it once a year. If the plenum has foil-wrapped insulation at its front, you can clean the evaporator; if the plenum is a sealed sheet metal box, do not attempt to open it. Here's how to clean an accessible evaporator:

Step 1: Remove foil-wrapped insulation at front of plenum; it's probably taped in place. Remove tape carefully, because you'll have to replace it later. Behind insulation is access plate, which is held in place by several screws. Remove screws and lift off plate.


Step 2: Clean entire underside of evaporator unit with stiff brush. A large hand mirror can help you see what you're doing. If you can't reach all the way back to clean entire area, slide evaporator out a little. Evaporator can be slid out even if it has rigid pipes connected to it, but be careful not to bend pipes.

Step 3: Clean tray below evaporator unit. This tray carries condensation away from evaporator. Pour 1 tablespoon of household bleach into weep hole in tray to prevent fungus growth. In extremely humid weather, check condensate drain and pan every other day. If there's much moisture in pan, weep hole from pan to drain line may be clogged. Open weep hole with piece of wire.

Step 4: Put unit back into place, reinstall plate, and tape insulation back over it.

Step 5: Turn back on air conditioner, and check for air leaks. Seal any leaks with duct tape.

You also may need to clean the condenser to get your air conditioning functioning properly.

Cleaning the Condenser

In most air-conditioning systems, the condenser unit is located outside the house and is prone to accumulate dirt and debris from trees, lawn mowing, and airborne dust. The condenser has a fan that moves air across the condenser coil. You must clean the coil on the intake side, so, before you turn off the power to the air conditioner, check to see which direction the air moves across the coils. Here's how to clean the condenser:


Step 1: Cut down any grass, weeds, or vines that have grown around condenser unit; they could be obstructing airflow.

Step 2: Clean condenser with commercial coil cleaner, available at refrigerator supply stores. Instructions for use are included. Flush coil clean (do not use hose); let dry.

Step 3: Clean fins with soft brush to remove accumulated dirt. You may have to remove protective grille to reach them. Do not clean fins with garden hose, as water could turn dirt into mud and compact it between fins. Clean fins very carefully: They're made of light-gauge aluminum and are easily damaged. If fins are bent, straighten them with fin comb, sold at most appliance parts stores. A fin comb is designed to slide into spaces between fins. Use it carefully to avoid damaging fins.

Step 4: Check concrete pad on which condenser rests to make sure it's level. Set carpenters' level front to back and side to side on top of unit. If pad has settled, lift pad with pry bar or piece of 2 x 4, then force gravel or rocks under concrete to level it.

During the fall and winter, outside condenser units should be protected from the elements to prevent leaf blockage and ice damage. Cover the condenser unit with a commercial condenser cover made to fit the shape of the unit or use heavy plastic sheeting secured with sturdy cord.

If you've cleaned everything you can and you're still not getting cool air, the problem could be the refrigerant.

Handling the Refrigerant

The coolant used in most air conditioning systems is a refrigerant called Freon. If the system does not contain the proper amount of Freon, little or no cooling will take place. If you suspect a Freon problem, call a professional service person to recharge the system. Caution: Do not try to charge your system's refrigerant lines.

Here's how you can repair the system's coolant lines. Examine the lines running from the condenser outside the evaporator inside the house. If the insulation is damaged or worn, it will cut down on the cooling efficiency of the unit and, therefore, should be replaced.

Replace damaged or worn coolant line insulation with new insulation of the same type as soon as possible. Follow manufacturer's instructions for installation.

Furnace Maintenance

Keep your furnace running efficiently and safely and prevent the hassle of breakdowns with a few simple maintenance procedures. We'll walk you through a series of simple steps that will keep it in tiptop shape. The entire maintenance operation takes less than three hours and costs only a few dollars

Remove the combustion chamber door

Flip the electrical power switch to Off. Remove the combustion chamber door by lifting up and pulling it out, and remove the burner cover (if you have one). It’s usually held in place by two screws.

When it comes to furnaces, an ounce of prevention truly is worth a pound of cure. To help you avert the hassle of your furnace’s dying or simply not putting out enough heat—just when you need it most—we’ll walk you through a series of simple steps that will keep it in tiptop shape. The entire maintenance operation takes less than three hours and costs only a few dollars—pretty cheap insurance.

we’ll focus on natural gas and propane-fueled furnaces. The maintenance tasks involving the blower chamber also apply to oil furnaces; however, oil furnace combustion chambers are very different and should only be worked on by professionals. Heat pumps, on the other hand, work more like a central air conditioner than like a furnace, so we won’t deal with them here.

Routine furnace maintenance and cleaning don’t require special skills. If you’re handy with a few basic hand tools, you can do it. We won’t be doing tricky or potentially dangerous stuff like adjusting the gas burners. Leave that for a pro. See “Symptoms That Call for a Heating Professional,” for more details.

Figure A: Gas Furnace Details

A forced-air furnace has four main sections: (1) the blower chamber; (2) the combustion chamber; (3) the return duct; and (4) the supply duct. When your thermostat calls for heat, the burners will kick on and begin to heat up the heat exchanger. The heat exchanger contains all the dangerous gases produced by combustion and vents them through the exhaust stack. When the heat exchanger gets hot enough, the blower starts. The blower pulls cooled air through the return duct, passes it over the warm heat exchanger and returns the warmed air to the rooms. Furnaces vary quite a bit in design, so yours may be somewhat different from this illustration. If confused, consult your service manual or a heating professional.

Tip: If your furnace has a standing pilot (a pilot that burns all the time), turning off the gas to the furnace when the heating season is over will save you as much as 5 percent per year on your gas bill. To relight the pilot, consult the instructions on your furnace’s gas valve

Carbon Monoxide Alarm

Install a carbon monoxide alarm on each floor. If you already have these alarms, test them. Carbon monoxide is an odorless, colorless gas sometimes produced by oil-, gas- and wood-burning appliances (furnaces, stoves, fireplaces, etc.). If this gas spills into your home in high enough concentrations, it can be fatal. Plug carbon monoxide alarms into electrical outlets or directly wire them to the electrical system. Do not install them in utility rooms, garages, kitchens or bathrooms.

Symptoms That Call for a Heating Professional

Symptom 1: Short cycling

When your furnace runs for only short periods (less than three minutes) before shutting off, the problem is called short cycling. This happens when the thermostat is out of adjustment or when the heat exchanger overheats and the burner automatically shuts off to prevent damage.

Symptom 2: Irregular flame

Properly functioning burners have fairly even rows of flames. If the flames are uneven or lean toward the back of the furnace, call in a pro. It could be a sign of dirty burners or a cracked heat exchanger.

Symptom 3: Odd noises or rumbling

While rumbling and popping aren’t cause for concern in a hot water or steam heating system, they shouldn’t be present if you have forced-air heat.

Symptom 4: Chronic illness

Frequent headaches or flu-like symptoms can be a sign of combustion gases leaking from a cracked heat exchanger or carbon monoxide leaking from an exhaust stack. With these symptoms, have your heating system checked out even if your carbon monoxide alarm remains silent.

Symptom 5: Soot deposits

Soot is a fine black powder that collects when combustion is incomplete. Its presence may indicate that your burners need adjusting or that you have a cracked heat exchanger that needs replacing.

Furnace Filters Save on Health and Budget

Furnace filters not only screen out unwanted pollens and debris from your heating and air conditioning systems (HVAC systems), but they also increase the system's productivity. By replacing them often, your air stays clean and healthy against allergens and other forms of bacteria that can be harmful to your lungs. Plus, fresh replacements keep the HVAC system running correctly by prolong its lifespan and reducing your utility bills by keeping it properly maintained. You should inspect them monthly (especially during heating or cooling season when your system is being used continuously) to see if they need cleaning or replacement. If they're not swapped routinely, then your system will have to work extra hard, reducing performance and increasing cost.

How to Clean or Replace
First, turn off the HVAC system and locate the service panel. Many of these panels can be removed by hand though you may need a screwdriver in some particular cases. Locate the furnace air filter near the intake-outtake blower, and check its dust level: Is it hard to see through? If you have a reusable model, then simply rinse away the dust particles in your sink or in your driveway with a hose; then wait for it to dry and put it back in place. If they're disposable, write down what size the unit takes, throw the dirty one away, buy and replace with a fresh product, and then turn your system back on.

Make your furnace last longer by changing the

Types of Furnace Filters
Furnace filters can either be disposable (with cardboard frames) or permanent (with fiberglass or metal framing). Disposable models are much cheaper, but require monthly replacement, therefore it is best to have several on hand in order to save you time throughout the year. Permanent brands are more cost-effective due to their reusability but require more work because of the routine cleaning. All furnace air filters come with a MERV (Minimum Efficiency Report Value) Rating. This reports the product's capability in trapping particles and helps you compare the performance of different brands: the higher the MERV rating, the more productive the filtration. Here are few different products out there, each with their own pros and cons:

Mechanical: Any dry?media product which simply captures unwanted components in its meshing. This includes any disposable model made out of manmade or natural fibers. These are not as effective for smaller particles, but are very effective if you don't have any severe allergies. Also, they're less expensive but have to be changed once a month. 
Electrostatic: Consists of polyester strands which become electrically charged as air flows through them. This static electricity attracts dust and pollens to the filter with slightly higher MERV rating than mechanical models. Most of these are bound to a metal frame and will not need replacing. They can often be used up to three months without cleaning. 
Electronic: An untraditional "filter" which doesn't have actual fibers or media to attract the debris. Rather, they have a grid of electrically charged wires that attract debris, but they are so efficient that within a few days their MERV rating may plummet due to excess dust buildup. Therefore, they have to be cleaned weekly. 
HEPA (High Efficiency Particle Absorber): The most efficient of all furnace air filters. It has no MERV rating because it actually exceeds its requirements and has a 99% efficiency testing. However, they are more expensive. Plus, due to its high-standard certification, there tend to be many imitation brands out there that may not be true HEPA products. Because of their valuable productivity, many of these products tend to only be used in high-sanitary environments, such as hospitals, laboratories, and surgical facilities and therefore they often aren't found in residential homes.

Cleaning the Blower Assembly of a Furnace

Step 1: Turn OFF power to furnace at service panel breaker box.
Flip breakers inside furnace OFF (if applicable). Turn furnace/fan switches inside furnace to OFF and turn thermostat to OFF.

Step 2: Remove blower assembly.
First disconnect fan motor wiring harness connector. Draw beforehand which way the wiring harness was hooked up. Remove any screws directly holding the fan housing lips on each side of housing and slide it out. DO NOT TOUCH the terminals on the capacitor. The capacitor is commonly found attached to the side of the blower housing. Be careful not to crimp, kink or damage any refrigerant lines which may be along the side of furnace and slightly in the way (mainly for blowers located at the bottom of the furnace). Protect refrigerant lines with a piece of cardboard. 

Step 3: Discharge and remove the capacitor if attached to the housing.
The capacitor is often fastened to the side of the blowing housing. If you do not see it, you may possibly have a shaded pole motor which does not require a capacitor so skip to Step 4. Or the capacitor may possibly be located elsewhere in the furnace. If so, skip to step 4. 

If your capacitor is located on the side of the blower housing, mark where the two wires connect to the capacitor. Using a long needlenose pliers with electrical-insulated grips, remove the wires from capacitor. When removing, be careful and be sure to NOT TOUCH THE TERMINALS. If you need to discharge the capacitor, use only a resistor-type jumper to safely discharge it. Only discharge if experienced in using the resistor-type jumper. Otherwise, just don't touch the terminals. Then remove the capacitor carefully.

Step 4: Remove the blower wheel and motor from housing.
Reach into squirrel cage and mark where the squirrel cage hub sets on the fan shaft. Mark it carefully as it must be returned to exact spot. Loosen the set screw in hub of squirrel cage (blower wheel).

Turn housing over, remove the bracket bolts to motor. Turn back over, take a piece of 2x4 wood, place against shaft and gently bump the motor shaft/motor out of blower wheel.

Then on the bottom of blower housing, there should be a section of housing that deflects the air and held in place with 2-4 screws. It will have to be moved or lifted back to remove the blower wheel. Do not bend it out of shape and beware how this comes apart throughout. Pictures from beginning to end are great for reference.

Step 5: Clean blower wheel. Go to a car wash that has spray wands. Spray blower wheel and blower housing (snail shell) with 1 full cycle of soap and 1 full cycle of rinse. You don't want too much water pressure from the wand as it may damage the fins. On the blower wheel fins, you'll find metal clips. These are balancers and care should be taken not to damage or remove them. Caution -- the fins are sharp so be careful. Allow to dry completely.

Step 6: Clean fan motor. Use a soft bristled brush to brush off fan motor and vacuum the outer fan motor ends. Oil if necessary.

Step 7: Reinstall blower wheel and motor into housing. Reinstall by reversing the removal steps. Make sure all is tight, but don't overtighten. Then after the wheel/motor/housing is back together, spin wheel in correct direction and make sure it doesn't wobble or knock/rub against anything. Also make sure the airflow is coming out through the bottom opening of blower housing without restriction. Don't forget to install and reconnect the capacitor.

Step 8: Reinstall blower assembly in furnace. First brush and vacuum gently inside the furnace before reinstalling the blower assembly. Then reinstall the blower assembly by reversing the procedure in step 2. 

Step 9: Finish up. Hook up wires, clean or change filter, vacuum and brush off a-coil if applicable using a soft-bristled brush. Old-style toilet brushes are great for brushing off a-coils. Turn on breakers and thermostat. Run the furnace through a few cycles before leaving it unattended.