A Quick Guide To The Parts That Make Up Your Air Conditioner If you’ve gotten a quote for installing a new central air conditioning unit recently, you might have been a bit confused by the lingo that was used to name the different parts of the system. What does a condenser and coil have to do with anything? You just wanted a quote on a new ac unit right? Let me shed a little light on the terms that describe each of the components that make up your air conditioning system. That round’ish piece of equipment that sits outside on the ground that everyone refers to as their air conditioner is technically referred to as a condenser. You’ll also hear it called the ‘outside unit’ as well. Part of your condenser is called a coil, or condenser coil, not to be confused with the evaporator coil that is inside your home attached to the furnace. This is the piece of your air conditioning system that most people never see. It’s contained in a metal box called a plenum, and sits on top of your furnace.

If you have a horizontal furnace in an attic, the evaporator coil will sit on one end of the furnace instead of on top. The ‘inside unit’ or ‘indoor coil’ are other common names that are used when talking about your evaporator coil. Lineset refers to the copper refrigerant lines that run from your condenser (the outside unit) to your evaporator coil. It’s very common for people to make the mistake of calling their outside unit the compressor instead of the condenser. A compressor is actually a big component that sits inside the condenser (the outside unit). The plenum is the metal box that sits on top of your furnace and houses the evaporator coil. The condensate drain is the white plastic (PVC) pipe that runs from your evaporator coil to the drain in your floor, or to the condensate pump that was installed if you don’t have a floor drain. This pipe allows the condensate (moisture) that the evaporator coil produces to be drained out of the plenum. I get questions about the names for these air conditioner components all the time, so hopefully this helps clear up any confusion as to what the different parts are called.

I’ll post another article explaining what each of these components do for those of you who want to dazzle your friends with your detailed knowledge of how air conditioning actually works.3 ton ac energy usageWHAT IS A HEAT PUMP?ice in ac unit outside Technically, a  is a mechanical-compression cyclesamsung window ac air filter refrigeration system that can be reversed to either heat or cool aInstallation for this type of system typically consists of two parts: an indoor unit called an air handler and an outdoor unit similar to a central air conditioner, but referred to asA compressor circulates refrigerant that absorbs and releases heat as it travels between the indoor and outdoor units. HOW DOES A HEAT PUMP WORK?

Think of a heat pump as a heat transporter constantly moving warm air from one place to another, to where its needed or not needed, depending on the season. Even in air that's seems too cold, heatWhen it's cold outside a heat pump extracts this outside heat and transfers it inside. When it’s warm outside, it reverses directions and acts like an air conditioner, removing heat One advantage of a heat pump is that it moves heat instead of generating heat, giving you more energy efficiency. powered by electricity, so you can save substantially on fuelFor example, a Trane  heat pump is among the HVAC industry’s most efficient, with a rating up to 19.00  and 9.00 . Note that heat pumps are best for moderate climates, and a supplemental heating source may be needed for lower temperatures. year-round solution for home comfort, Trane heat pumps can become a key part of your matched system. An independent Trane dealer can help

you decide if a heat pump system is right for you.Air conditioning systems rely on movement and the change of state (evaporation and condensation) of refrigerants between an outdoor condenser coil and an indoor evaporator coil. The lines that carry the refrigerant between the evaporator and condenser coils and through the compressor and expansion device typically are copper. The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line. The smaller uninsulated line typically carries a warm liquid. It is most often called the liquid line. Where the evaporator coil is higher than the condensing unit, the suction line should slope down toward the condensing unit with a slope of at least ¼ inch per foot to allow oil to flow back to the condensing unit. The oil, which is used to lubricate the compressor, travels with the refrigerant through the system. Any extra piping may be coiled near the evaporator coil.

The line should be coiled horizontally rather than vertically. Again, the lines should allow oil to flow back to the condensing unit. With R-22 (old refrigerant), operating pressures in the lines are typically in the order of 70 psi on the suction side of the system and more than 230 psi on the discharge side. R-410A (modern refrigerant) might have a suction pressure of about 120 psi and a discharge pressure of 380 psi. There is considerable variation in these numbers and they are not critical for home inspectors to know because we are not testing refrigerant pressure. Because refrigerants are a gas at atmospheric temperature and pressure, leakage through the lines will dissipate as a gas and may leave an oil residue. At atmospheric pressure, R-22 has a boiling point of roughly -41°F, and R-410A is around -63ºF. In some installations, you will find a filter/dryer in the liquid line. Filter/dryers clean and dry the refrigerant. Installers often add these to a system when the compressor is replaced or if a refrigerant leak has required recharging.

They help remove any contaminants. They are roughly the size and shape of a soft drink can. They may be located in the liquid line near the condenser outlet or near the expansion device, close to the evaporator. Many have an arrow on them to show the direction of flow. If possible, check that the arrow is pointing in the right direction. Bidirectional units with arrows pointing both ways are acceptable. Frost accumulation just past the filter/dryer indicates a partially plugged unit and service should be recommended. Some air conditioning units and most heat pumps have accumulators designed to prevent liquid from getting into the compressor. Compressors are designed to pump gases and become damaged if liquids are introduced. Accumulators on air conditioning systems typically are located in the condenser cabinet just upstream of the compressor. Typically, they are metal cylinders, with refrigerant lines going into and coming out of the top. There is not much to inspect. Refrigerant lines should be supported every 5 to 6 feet.

Bends in refrigerant lines should have a minimum 12-inch radius. A sight glass may be installed on the liquid line, usually near the condenser. This allows the service person to check refrigerant levels. If bubbling is noted in the sight glass on an R-22 unit, this indicates possible problems and service should be recommended. It is unlikely there will be a sight glass on an R-410A system, but if there is, bubbles do not indicate a problem. The sight glass is about 1 inch in diameter. Many sight glasses have a colored ring. If the ring color changes, this indicates moisture in the refrigerant. This is a serious condition. As little as one tablespoon of moisture in the refrigerant system will destroy a compressor in a few months. Sight glass is more common on commercial systems than on home air conditioning systems. Sight glass is especially rare on newer residential equipment, as charging methods have changed over mon refrigerant line problems include the following: Let’s examine two of these common conditions: leaking and

Oil residue on the line usually indicates a leak in the piping, often at a connection. Because oil travels through the system with the refrigerant, a leak often will show up as an oil stain. Escaping refrigerant boils off and leaves no trace other than the oil. CausesRefrigerant leakage is usually the result of corrosion or mechanical damage. Corrosion and sludge Corrosion is often the result of contaminants in the system: copper lines touching galvanized ductwork or other dissimilar metals; or a corrosive atmosphere in the house caused by chemical storage, furniture refinishing, gypsum board with high sulfur content (Chinese drywall) or some other reason. Mechanical damageMechanical damage to refrigerant lines can occur at the outdoor unit if the lines are bumped by a lawn mower, for example. Mechanical damage also may be possible in places where the lines go through the exterior house wall. SettlementSettlement of the condenser or building can stress the copper lines.

People playing or working around the air conditioner may step on the lines. The lines running through the house can be damaged by driven nails or careless handling of storage, for example. ImplicationsIf the refrigerant leaks out, the system performance will deteriorate and the house will be less comfortable. Ultimately, the compressor may fail or the system may shut down. StrategySince refrigerant lines do not have any connections or joints that may leak except at the coils, concentrate on the connections to the coils at either end, where visible. If there is a thermostatic expansion valve, check its connections. Check along the length of the line for evidence of mechanical damage, particularly in exposed areas and at the interior and exterior penetration points through the house wall. Refrigerant lines need support so that joints aren’t stressed under the weight of the lines. On attic units, pay attention to where the lines disappear into walls or ceilings. Lines through the wallWhere refrigerant lines go through walls, the hole in the wall should be considerably larger than the refrigerant lines, and the lines ideally should be (but are not commonly) in conduit at the point at which they go through the wall.

The flexible material should seal the inner and outer ends of the conduit to allow movement but also to prevent moisture and insects from entering the building and to prevent heat from going out of the building. Oil StainsLook for evidence of oil stains on the refrigerant lines. Service technicians use leak detection fluids, halide torches or electronic leak detectors. These are beyond the scope of home inspectors. The large-diameter line (suction line or gas line) should be insulated along its entire length. The insulation has two functions: CausesInsulation may be missing because of the following reasons: StrategyLook for the insulation to be intact along its entire length. Pay particular attention to the outdoor section of the suction line. In this article, we introduced several important topics related to refrigerant lines from air conditioners. You can find much more information in the ASHI@HOME training program. Thanks to Roger Hankey and Kevin O’Hornett for their thoughtful review and input.