Air conditioning is one of the most taken for granted inventions of modern man. During the summer months when temperatures around the country often exceed 100 degrees, walking into a cool home is refreshing. What happens when you come home, and the air conditioner isn’t working? As humans, we go through a lot of emotions when something isn’t the way we expect it to be.
Once your emotions have settled and you have managed to cool yourself down a bit, it is time to think about calling a repairman or doing the work yourself. This article will cover the various types of air conditioners as well as how to troubleshoot the problem and buy air conditioner parts online.
How Air Conditioners Work
Air conditioners, for the most part, are simple machines. There are a lot of pieces that go into making them work, but the mechanics of it are simple. Power is supplied to the condenser which begins the air conditioning cycle. Inside the condenser, the refrigerant is condensed and pressurized, which causes it to become extremely cold and increases the pressure.
The high pressured refrigerant is sent through the copper tubing to the evaporator. The evaporator draws warm air into the system and blows it over the cold coils where the coolant is cycling through. This process causes the air to become chilled while heating and expanding the refrigerant.
Once the refrigerant has low pressure and a higher temperature, it is sent back to the compressor to start the cycle all over again. The result is air that is cooler than the ambient air of the home blown around to keep the rooms at a more comfortable temperature.
Types of Air Conditioning Units
While the process of cooling the air is the same for all air conditioning units, many brands have more (or less) parts added to the equation. Let’s examine the various types of air conditioning units.
Central AC Systems
A central AC is generally part of a heating, venting and air conditioning (HVAC) unit. However, some are cooling only, or heating and cooling. Likewise, there are also additional HVAC units, such as humidifiers, driers, and other components.
The central HVAC unit is a closet mounted unit with a large condenser and evaporator built into a cabinet or in the ceiling. The process of cooling the air mentioned above still applies. However, the cold air is then blown through ductwork hidden in the ceilings, floors, or walls and enters the various rooms of the home through vents.
These units will have a replaceable filter for the evaporator and a thermostat mounted on the wall to control the power, temperature and cooling modes.
Split AC systems & Ductless Mini-Split Systems
A Split AC system is more commonly found in residential areas around the country. The main difference between a split system and a central AC system mentioned above is the location of the condenser.
A split system has the evaporator and blower mounted inside the home (in a closet or the attic, etc.) while the condenser sits outside the home.
The two are connected by the thermostat wires for power control, as well as high and low-pressure lines for the refrigerant to travel back and forth.
A Mini-Split system doesn’t use ductwork like the central and split AC systems. Instead, each room has a miniature evaporator and blower mounted that is usually controlled by a remote instead of a centralized thermostat. A mini-split system is more expensive to set up initially but can save a lot of money in the long run by only cooling rooms you need to be cooled.
Window/Room AC Systems
Another popular type of AC system is the window unit. This is a room air conditioner that sits in a window (there are also through-the-wall units). These units are smaller (obviously) to fit in a window and can produce enough cold air to keep a single room cool.
The units themselves are more affordable than any of the previous systems. However, you will need a window or room unit in each room of the home, which can add up in total costs. The units also require a lot of electricity, and your monthly energy bill can see a steep increase during the warmer months.
Portable AC Systems
Like a window AC, a portable air conditioning system is designed to keep a small area or room cool. These all-in-one units still need to be near a window for the exhaust vent. However, they are all-inclusive, and most units are mounted on wheels for easy portability. You can move them from one room to the next, plug into an existing outlet and begin cooling a room right away.
The downside to these units is that they require a lot of power to cool a room larger than about 65 square feet. If you have a place without a window to vent out of, you shouldn’t use a portable AC system. The exhaust fumes will not only make the room stuffy, muggy, and difficult to breathe in but will counteract the cooling by releasing hot air back into the room.
RV AC Systems
If you own an RV chances are you have an air conditioning system already installed. There will be a thermostat on the wall and room temperature sensors throughout the rig. The main unit, though, is mounted on the top of the RV to save space inside.
Under the shell, you will find a unit similar to a window AC. The compressor, condenser, and evaporator are all included within the shell space. The system works in the same way as well. Once the air is cooled, it is pushed through the ventilation system to blow cold air into the RV.
Car AC Systems
A car or truck AC system is slightly different. Each part is separated and connected through high and low-pressure lines, much like a split AC system. However, all of the components are spread around the engine compartment or under the firewall.
The system uses the compressor to condense and liquidize the refrigerant where it is sent through copper tubing to be cooled. As the cold refrigerant chills the coils in the evaporator, the air is drawn through the coils by the cabin blower and pushed out the vents into the cabin area of the car.
Learn about portable Car and Truck AC units here.
Signs That Your AC Needs Repair
Besides walking into a warm home, there are other signs your air conditioner may be going out. Let’s take a look at the most common tell-tale signs.
When the AC kicks on, you should be able to feel cool air coming from the vents. If the air coming out isn’t cold, there may be something wrong with your air unit. This can be a simple fix such as replacing the filter or something more complicated like a burnt-out capacitor on the condenser unit.
If the airflow coming from the vents or the AC unit (for portable or window systems) is low but cool, you could have a clog somewhere. The most likely culprit is the filter, but don’t neglect to check the ductwork or the evaporator blower motor.
Another big sign is that the AC system appears to be working right, and the air is cool. However, the system itself comes on and off more frequently than it used to. In most cases, a faulty thermostat is to blame. However, it can also be a problem with the blower motor or the wiring to the evaporator unit.
High humidity levels are an indication that there is something wrong with the evaporator. Generally, the evaporator easily removes excess moisture from the air and coils. However, if the system is overworked, the temperature can drop below the dew point, causing excess condensation. This excess then gets moved around the home, creating a humid atmosphere.
The first thing to check for is open doors or windows. If you run the AC with the house opened up, the temperature will never reach the setpoint, and the system will continue to run, falling below the dew point. Other causes can be a clogged drain, dirty air filter or inefficient blower motor.
A split system will have leaks from the evaporator unit and are mostly noticed when the system shuts off. If the drain is clogged the water build-up in the drip tray will be lifted by the blower motor. When the system shuts off, gravity brings the water down, and it escapes from access panels and other areas.
If you notice the condenser area is wet, this is generally a sign of freezing pipes and is the result of the condenser not working properly, or there isn’t enough refrigerant in the system.
In most cases, you will notice a moldy or musty odor when the system isn’t running, or just after it kicks on. If this happens, the culprit is generally a mixture of dirty ducting, a clogged filter and excess moisture build-up. Combined, the ducting, filter and blower motor can begin to attract and grow mold spores.
When the system shuts off, the warmer air in the ducts will begin to permeate the odor. If the symptoms are more internal, you will notice the smell as soon as the air kicks on, and the airflow travels through the vents until the temperature of the air drops enough to cover the odor.
AC Replacement Parts Explained
There are a lot of cases where the homeowner can test and replace AC parts themselves. However, it should be noted that most residential and commercial air systems run on a direct-connect 220v electrical supply. Care should be taken to disable power before removing or testing parts.
You should also note that removing or adding refrigerant to an air conditioner system takes special tools and knowledge and must be done by a trained professional.
In most states, it is illegal to purchase refrigerant without a license or expel any refrigerant at all. This can lead to a fine of up to $10,000. If you suspect the problem lies in the refrigerant, it is best to call a professional for service or diagnosis.
The evaporator brings in the high-pressure liquid refrigerant and pushes it through the cooling coils where the air that passes through is chilled. The process of this heat exchange causes the refrigerant to heat up quickly and expand into a vapor. The pressure of the liquid is reduced, and the evaporator sends the low-pressure vapor back to the compressor to repeat the cycle.
Inside the evaporator unit, you will find the blower. This is generally a cage or hamster wheel style fan. The primary job of the blower is to pull warm air in and through the coils and then push, or blow, the cold air through the ductwork and out of the vents.
The expansion valve is part of the condenser unit, and it where the flow control of the refrigerant takes place. The valve regulates the flow from the condenser to the evaporator to keep the pressure of the refrigerant at a constant level.
The thermostat is usually mounted on the wall in a centralized location. In residential areas, this is a hallway or a main room of the house.
The thermostat is where you set the preferred temperature, and when the ambient temperature of the home is higher than the set temp, the AC will kick on. When the house is cooled to the set temp, the AC will kick-off.
There are analog and digital thermostats with varying degrees of control options and features. In cars, there isn’t a thermostat. Instead, you turn the AC on or off manually, though you can select the blower speed.
Filters are essential for keeping the AC clean from debris and dust build-up. A clogged filter can lead to an overheated or overworked AC system as well as being the first step to a host of known AC issues.
Window and portable units use a filter screen that can be washed and replaced. Residential and commercial systems use a replaceable fiber filter that should be replaced every 30 to 90 days. For automotive systems, there is a cabin filter that should be replaced once a year (or more in hotter climates).
Belts are less common in window, portable, and residential units. However, they are a crucial part of automotive ACs. The belt drives the AC fan, compressor, and clutch and without the belt, the AC system won’t run at all.
If your car AC is acting up or not pushing any air, the first thing you should check is the belt. In modern cars, there is a single belt that is responsible for more than just the AC. If this belt breaks, your entire vehicle will have problems running, not only the AC.
All AC units will have a fan of some sort to remove the hot air from the compressor. In split units, this is a large fan affixed to the top of the housing on the outdoor unit. In window and portable units, the fan is a hamster-wheel style fan that circulates the air towards the rear of the machines.
If the fan motor goes out, the compressor can overheat, causing the system to shut down (most have a cut-off switch to prevent damage).
All air conditioning systems need a refrigerant to cool the air. Before 2003 Freon was used (labeled as R22 or R12 for home and automotive applications). The release of Freon, a CFC, is known to promote the depletion of the ozone layer and is being phased out. R22 and R12 are no longer being manufactured, and the supply already made is being sold at very high prices.
Newer systems use R-410a (for homes) and R-134a (for automotive applications.). These refrigerants are non-Freon and do not contain CFCs. They are considered safer for the environment and are now the primary refrigerants used in all systems.
The job of the refrigerant is to be pressurized and heated to allow the heat transfer of the air being blown over the coils. A small amount of lubrication oil is mixed in with all refrigerants which act to keep the internal parts lubricated and functioning properly.
The capacitor is mounted in the access panel of your condensing unit (the large box outside your home). This small cylinder is connected to the thermostat and from there to the compressor, fan, and even the evaporator and blower motor inside. When the thermostat tells the system, it is time to turn on (or off) the capacitor acts like a jumper cable, sending an electrical current to start the system.
Condenser & Condenser Coil
The condenser and condenser coil take the compressed refrigerant and cool it down before it can move to the evaporator. The process is quick since the vapor is at a high agitation state from being compressed. This is where you will find the expansion valve, too. Mixed within the cooling coils before the line goes to the evaporator.
Learn about condensers here.
The air compressor is the heart of the entire unit. Its job is to take in the low-pressure vapor refrigerant and compress it into a high-pressure vapor.
The compressor then pumps the hot vapor through the coils, which cause it to become cold. It is then sent on as a cold liquid to an expansion valve.
All air conditioning systems have a compressor of some type, regardless of application. Servicing a compressor should be done by a professional because it deals with the transfer of refrigerant.
Read more about compressors in this article.
Remote Control & Controller System
On window and portable AC units (and some smart home digital thermostats), you control the system with a remote control. These remote controls allow you to set the temperature, turn the unit on or off and adjust airflow, speed, and power settings.
For most systems int eh home there are two fan motors. The first is the motor for the fan on the condenser unit outside. The second is the motor that controls the blower fans in the evaporator unit.
As with all electrical components, the motors will eventually burn out and need to be replaced. This is something that most homeowners can do with simple tools. As long as care is taken to disable power to the motors and other components before removal, the job shouldn’t take longer than an hour (depending on the rust or wear on the mounting bolts.).
Car AC units, as well as window and portable ACs, will have adjustable louvers. These are the small blades on the vents that allow you to control airflow direction. Over time, with repeated adjustments, the louvers can break or come off. This is the easiest part of a system to replace, although finding the correct replacement louvers can take a bit of research.
Why Are Car AC Parts Different?
An automotive air conditioning system is slightly different in the functionality of the parts. While both home and car ACs are designed to serve the same purpose, they do go about it in different ways.
A car AC is smaller, and the parts are spread further apart in most cases. The main difference is that a thermostat doesn’t control a car AC. Instead, it is either on (clutch engaged) or off (clutch disengaged). However, even with the compressor clutch disengaged, the system is still running.
The system runs when the car is on because it is belt driven and the belts spin when the engine is running. The compressor clutch is the key element that turns the system on to blow cold air through the cabin or lets the refrigerant cycle around until it is needed. Home and commercial ACs don’t have a clutch, nor are they belt-driven. Everything on these systems is electrical.
Common Brands of AC Units
Let’s take a look at some of the most popular brands of the different air conditioning systems we have covered in this article. We will also point out what to watch for when purchasing a specific brand or style.
|Central & Split System||Comment|
|Coleman||Coleman is a name more associated with camping gear. However, they produce a line of central and split system units. They also have an unrivaled warranty. This includes a lifetime warranty on the compressor. The main issue here is finding parts, which can be challenging to obtain and costly to replace.|
|LG||LG makes a lot of electronics and home accessories, including split system ACs. Known for reliability and accessibility, the LG systems are efficient, quiet, and cost-effective. Their downside is in the warranty, which is limited and difficult to claim against. If the unit does break down, prepare to be on your own.|
|Hisense||Hisense is relatively new to the American market and is known for making more-than-affordable appliances. Their systems will be cheaper to purchase and install, but their dependability leaves a bit to be desired.|
|Lennox||Lennox is a name that has been around for years and conjures images of an older man in overalls. Reliable, warrantied, and dependable central and split AC units have been the backbone of this company for decades. One main issue is cost-effectiveness. Relying on brand recognition, they aren’t about to lower prices to be more competitive.|
|Carrier||Carrier has long been used for commercial applications and in business that requires large, dependable units. For the residential side, the initial installation costs may be more than you want to pay, but you won’t have to worry about the unit breaking down for at least 20 years.|
|Rheem||Rheem entered the commercial market long before they ventured into the residential market, and their prices reflect that. While their home units are dependable and long-lasting, you will pay less with almost every other name brand unit. Not many will last longer though, but the trade-off isn’t worth it to some.|
|Ruud||Rudd is about as middle of the road as you can get. They aren’t fancy, but they aren’t bottom of the barrel, either. Their cost, warranties, and dependability all fall in the “about-average” section of the market.|
|Goodman||Goodman is a name you can trust when it comes to split ACs. These units are cost-effective and trusted by many multi-home complexes around the country. They offer unrivaled attention to detail and parts are available through virtually any online retailer, making them accessible as well as affordable. Just don’t expect too much from the limited warranties on the parts. You will be talked out of a claim if you allow it.|
|Amana||Amana is better at small appliance cooling than home cooling, but that doesn’t stop them from trying. While they make a better refrigerator than AC, their split systems and central systems are cost-effective and will save you money on your energy bill – while they are running, at least.|
|Trane||Nothing runs like a Trane is the catchphrase that has entered our homes for decades, and we know the company to be reliable and durable. Parts for these units must be exact, though, and anything other than the Trane name going in the units will void the warranty.|
|American Standard||American Standard is one of the most cost-effective, name brands available today. American Standard is readily available at most home improvement stores, and their parts are affordable. However, with cheaper parts, you will be doing more replacements for worn pieces than you will with other, more expensive units.|
|Daikin||The Japanese maker, Daikin, has an affordable answer to your home’s cooling systems. Their main drawback is in locating replacement parts. It seems they have gone out of their way to be different enough to be almost exclusive. Finding parts is better done online than in person, just make sure you have the right model numbers to ensure a proper fit.|
|LG||When it comes to a window or through-the-wall units, LG is king. The features and prices make the units efficient, energy-saving, and affordable. You won’t find a selection that offers more anywhere else. Expect to pay for that selection, though.|
|Haier||Haier is eye-catching because of its low price tag. While the units are energy-efficient, the catch is they are only cost-effective on low settings, which won’t’ cool off a walk-in closet. If you want long-term savings, Haier isn’t the right choice. However, if you need a temporary fix or are just looking to cool off a single room for a short time, their price is unmatched.|
|Arctic King||Arctic King was once a powerhouse in the window unit market. Balancing reliability and cost, the company once ruled the market as their moniker suggests. In the last 10 years, though, they have sacrificed production by using cheaper parts. While they will cool your home, you will need service more often.|
|GE||GE has a thumb in every pie, and the window air conditioning market is one such pie. GE is as reliable as they are well known, and the AC industry side of the company gives you exactly what they say. The warranty could be better, though, and many find that having to go through Sears to make a claim can be a problem at times.|
|Frigidaire||Frigidaire, like Amana, uses their technology to enter new markets. When they began producing window units, the product was sub-par. Nowadays, they are more reliable and energy-efficient, but for the price, you can do better with less long-term worry.|
|LG||Unlike the window units, the LG portable units are not as reliable. The machines are loud and require more maintenance during setup than should be allowed. However, once set up, connected and the exhaust and drain tubes are correctly affixed, the units will cool an entire room quickly.|
|GE||GE portable units aren’t as reliable as the rest of the GE line. You will go through a few warranty claims (as reported by many owners), and GE customer service isn’t up to par. However, with the bad out of the way, for a temporary unit that you want to use sparingly or only for a couple of seasons, the price point is low, and the units will cool a room efficiently.|
|Dometic||Known primarily for their RV air conditioners, the Dometic portable units are surprisingly good. They come with feature sets typically only found in window units and are durable. On top of that, customer service is quick to respond and overly helpful.|
|Friedrich||Friedrich is not quite a household name, but it should be. The portable AC units are durable, reliable, and cost-effective. They will zap more energy than other models on this list, but they withstand a lot more, too. One major issue is the reservoir shutoff, which kills the nit if the drip tray becomes full. This happens more than it should for a unit designed to evaporate the tray regularly.|
|DeLonghi||DeLonghi also owns the Braun and Kenwood, if you aren’t familiar with the Italian name. The units do cool efficiently. However, they are loud and cumbersome. If you plan to sleep with the unit in the bedroom, plan on a restless night. If you have hardwood flooring, the wheels can cause groves or wear marks because of the weight the wheels have to bear.|
|RV AC Brands||Comment|
|Coleman & Coleman RV||Coleman and specifically the Coleman RV branch makes a reliable and cost-effective AC unit for your motor home. The sensors are a bit confusing and can be triggered by the smallest drafts. However, with proper placement and planning, this can be avoided.|
|Dometic||Dometic RV air conditioners are the benchmark of the market. There is little bad to say about these machines except that a new install can be costly. However, once installed, they are virtually worry-free and easy to maintain.|
Cleaning Your AC
Regular maintenance of your AC unit is paramount if you want it to run efficiently and cool the home in a timely manner. There are a few things you can do to keep the unit working correctly.
Change the filter out promptly. Each filter will have a life span printed on the packaging. Usually, these filters will last between 30 and 90 days. You should change the filter before this time is up and not run the air conditioner without a filter.
Cleaning the coils yearly will help prevent build-up, promote airflow, and keep the drains clean. The evaporator coils will get caked with dirt and dust from use. This is normal. Opening the access panel will allow you to get to the coils. A coil cleaning solution and coil brush should be used. The fins on the coils and evaporator should remain straight. Any bends will block airflow.
On the condenser unit, you can clean off the vents with a pressure washer or garden hose. If the debris has accumulated and begun to cling to the vents and coils, you can use a propane torch to burn them clean. Care should be taken not to burn the wiring or apply direct heat to any portion of the unit except the vents and coils.
DIY Air Conditioning Repair
There are two portions of the air conditioner that can cause problems, refrigerant leaks, and electrical components. For refrigerant leaks, the culprit usually responsible will be the fill valve cores (Schrader valve). Over time the rubber o-rings on the cores will go bad, allowing small amounts of refrigerant to escape.
However, it takes a specialized tool and knowledge of the system to replace a valve core without leaking refrigerant (which is illegal). While you can purchase the core replacement tool, when the refrigerant system is involved, it is best to call in a licensed professional.
For the electrical system, the most common failed components are the capacitor, contactor, and fan motors. The homeowner can replace each of these parts without the need to contact a professional. However, you need to first shut off the power supply to the condenser unit and short the terminals on the capacitor (it stores a small amount of power).
Because the capacitor and contactor are explicitly wired, it is essential to label the wires before removing them and reattach them in the correct spots. The fan motors (condenser unit or blower motor) can be removed from the units and replaced on a workbench or in a garage. Make sure the motors are the correct size, power, and rotational direction before purchasing a new one.
Buying Online Vs. a Store Near Me
Depending on the part and what you need, it may be more beneficial to shop at a local store. Other times it can be quicker to shop online. How can you tell which to do? In short, both methods will eventually get you what you need. However, there are certain instances when online shopping will be more beneficial.
If you know the part number, you can quickly get quotes from various online vendors. Of our favorites, Amazon.com and Sylvane are among the most reliable. Both will offer competitive prices on older models and specific parts for your systems.
You may want to shop locally though, and there are a couple of reasons that make this the smarter choice. First is timing. If you come home and your AC is broken, you will need the fix as soon as possible. You may not have the time to wait on shipping and will spend whatever it costs to get the part right now. In this case, a local HVAC supplier will be your best bet.
The second reason for shopping local is when you can’t identify the part number. Perhaps age has removed the number, or your OEM part doesn’t have a part number stamped on it. When this happens, you can take the piece to a local shop and compare it to those on the shelf. Making sure the connections, mounting holes, and sizes are all a perfect match.
Frequently Asked Questions
Now we will answer some of the more common questions about air conditioning units.
Which gas is used in ACs?
For most residential and commercial air conditioners, the refrigerant used is either R22 or R410a. For automotive ACs the refrigerant is either R12, R134a or the newer R1234yf types. You should note that both R12 and R22 are CFC refrigerants (commonly called Freon) and are being outlawed.
What is the difference between R-22 and R-410a refrigerants?
R22, also called Freon, is a CFC based refrigerant that is known to promote ozone depletion. R134a, known as Puron, does not contain CFCs and is safer for the environment. Both liquids become gases under pressure and will heat up under pressure. This is what makes the system cool the air as the heat transfer of the gases causes a rapid temperature decline during a state change.
Where can I find the model and serial numbers of my AC unit?
For split AC systems commonly found in homes, the model and serial numbers will be found in the owner’s manual or on a sticker located on the condenser unit. This sticker is usually found on the access panel to the capacitor and contactor area.
How do I know the part number of an AC replacement part?
Most AC components will have a model number stamped into the framework of the unit. For example, the fan motors will have a plate where the information is stamped. The compressors will have a stamp located on the pump housing or sometimes as a plastic tag attached to the mounting bolt holes. If you are in doubt, the manufacturer will have OEM part numbers for your specific unit listed on their websites or in the owner’s manual.
Are air conditioner parts covered with a warranty?
The exact parts covered in a warranty will vary by manufacturer. In general, larger parts such as the blower, compressor, lines, housings, and electrical components are included. Replaceable parts such as the capacitors or contactors will not, usually, be covered.
How often should AC coils be cleaned?
It is advised to clean the AC coils once per season before putting the AC to use, or every six months. If you find that the filter has been perforated an extra cleaning may be needed during the season.
How many parts does an AC have?
The number of parts will change with each manufacturer. However, the primary components won’t change. The AC system will have at least five elements: compressor, evaporator, fan, coils, and electrical parts (contactor, capacitor, etc.). Depending on how the items are grouped, the size of the unit and if it has any other purposes (such as heating), the number of parts will increase.
As you can see, having an air conditioning system is almost a necessity. In the late spring and summer months, central air or split system air is crucial. Depending on where you live, you may get away with a single room or window air conditioner or even a portable AC.
With ownership comes responsibility, though. To help keep the energy costs down, cool your home or room efficiently, and keep the unit working correctly, you will need to do some maintenance. When the time comes, knowing what parts to replace and when it is better to call a professional will save you a lot of headaches.
Shopping online may be the best option and is undoubtedly the fastest. You can get multiple quotes for your parts in a short amount of time, without having to travel all over town. When time is an issue because your home isn’t being cooled, every minute helps.