What is an AC Condenser?

ac condenser
What is an air conditioner condenser? The AC condenser unit is one of the key components within a cooling HVAC system. Various issues can affect how your AC condenser works, and all of them affect the overall function of your AC system. We'll explain what you need to know to ensure your AC condenser is working, and what to do if it starts having problems.

Air Conditioning Parts Breakdown

Before diving into the details of the AC condenser, it helps to have a clear overview of the parts of an HVAC system and how they work together to keep the desired temperature in your home. Air Conditioning Parts Breakdown

1. Thermostat

Your thermostat is probably the most familiar part of your AC system, and the one that you interact with most frequently. After you set the thermostat manually or program it in advance, it works to keep your home at a specific temperature. Once the thermostat detects that the temperature in your home is too hot or too cold, it triggers the evaporator and condenser coil combination or the heat exchanger to start circulating hot or cold air, depending on the desired temperature.

2. Furnace

The furnace provides heat via one of four heat sources:
  • Combustion of natural gas, propane, oil or coal
  • Heat pump
  • Solar energy
  • Electric resistance
The furnace is typically installed in a cellar, basement or attic, or a closet space specifically designated to store it. It is the largest component of an HVAC system and a crucial one. Its job is to heat air for distribution to other rooms of the home. If the furnace is powered by a heat pump, it may come with an air handler that helps move air through the system. Other types of furnaces, however, have a blower instead.

3. Heat Exchanger

The heat exchanger is a part of the furnace housing. It turns on when the thermostat triggers the furnace to start heating air when the temperature is cold enough. The exchanger brings in cold air, the furnace heats it and then the heated air circulates through the ducts to heat each room.

4. Evaporator Coil

The evaporator coil is essential to the cooling processes of an HVAC system and acts as a counterpart to the heat exchanger. When the thermostat indicates the ambient temperature is hotter than desired, the evaporator coil works like a car's radiator to cool air that then circulates through the ducts. The evaporator coil is typically located on or near the unit's exterior, making it a critical part of the indoor AC unit.

5. AC Condenser

An AC condenser unit connects to the evaporator coil. It sits on the outside of the home and is full of refrigerant gas. After the heat exchanger uses exterior air to cool the refrigerant, the condensing unit pumps the cooled liquid to the evaporator coil. The coil then evaporates the liquid refrigerant back into a gas.

6. Refrigerant Lines

These are tubes made from metals resistant to heat and cold, typically aluminum or copper. They transport the system's refrigerant into the condenser in gaseous form. They also return the refrigerant to the evaporator once it has been converted to liquid.

7. Ductwork

Central air conditioning units rely on a series of ducts to facilitate the flow of warmed or cooled air to all the areas of a home. Ductwork is typically manufactured from lightweight aluminum, but other materials such as plastics, polyurethane or fiberglass are sometimes used.

How Condensers Work

Condensers are one type of heat exchanger. They force pressurized refrigerant to undergo condensation, changing the substance from a gas back into a liquid. The condenser coil is the main component of a condenser unit, as the refrigerant must flow through the tubing. Central AC systems usually place the condenser unit outside of the building.

Types of Condensers

There are three types of condenser you might encounter:
  • Air-cooled condensers pass air over the condenser coil to remove heat.
  • Water-cooled condensers apply water directly to the condenser coil to remove heat.
  • Evaporative condensers let water evaporate into the ambient air, typically without using a refrigerant.
The vast majority of residential HVAC systems use the air-cooled type of condenser. Parts of an AC Condenser

Parts of a Condenser

Split AC systems and heat pump systems both use condensers which consist of the same basic set of parts. The condenser cabinet — the name for the condenser unit as a whole — houses the actual condenser coil along with a home AC compressor, a fan and various controls.

The Condenser Coil

The condenser coil itself can have two compositions: Copper tubing with aluminum fins, or fully aluminum tubing. All-aluminum tubing is typically a good option for when rapid heat transfer is the priority. The coil must stay as clean as possible if its heat transfer efficiency is to remain at peak.

The Condenser Fan

The fan circulates air to pass across the coil and trigger heat transfer. If the fan fails or the airflow is blocked, the compressor might lose function or fail completely. Maximum airflow equals maximum heat transfer, so keep the area around the fan, coil and compressor free of dirt and debris.

The Condenser Compressor

The compressor is what actually compresses the refrigerant, pumping it into the coil while it is still a hot gas. The condenser then turns the hot gas into a hot liquid, which moves on to the evaporator coil to cool and expand. The compressor AC function is the heart of air cooling.

AC Condenser in Air Conditioning

Condensers in an air conditioning-only system don't have too many controls to worry about. Capacitors start and run the necessary motors, and a contactor turns power to the condenser on and off. One optional control is a brownout time delay, which turns off the contactor if it detects a voltage drop bringing too much current into the motors.

Heat Pump Condenser in Heating

HVAC condensers may pull double duty and help with heating in systems with a heat pump. In these setups, there are more complex controls to consider. This is because the flow of compressed gas must be able to reverse depending on whether the system needs to produce heated or cooled air. The additional controls include an adjustable temperature sensor, reversing valve and defrost timer. In a heating context, the condenser takes heat from air outside the house and cools it. This causes the coil to become cold enough to collect frost, which depletes airflow and makes the coil less effective. An automatic defrost control ensures the unit changes into air cooling mode even if the condenser's fan is not running. This brings hot gas through the coil, defrosting it. Once this happens, the system automatically resumes heating.

Do Condensers Break or Go Bad?

As we have discussed, AC condenser units are not one component but a grouping of many parts. That means if one or more of the parts fails, breaks or wears out, the whole unit can fail. Some of the potential issues that can cause a condenser to break or go bad include the following.

Failing Control Board

A condenser unit needs the control board for its various parts to communicate properly. If the control board is faulty or fails completely, the air condenser unit's components cannot work in concert. This results in things like the compressor not switching on or off, which can cause strain that makes the whole unit fail.

Dirty Components

Because the condenser in most air conditioner units is located outside, it's common for the unit to pick up dirt or debris over time. With regular cleaning, dirty components do not usually become a long-term issue for a condenser. However, leaving debris and dirt on the condenser and coil can cause the air conditioner to run inefficiently, and lead to premature wear and tear that may necessitate repair or replacement of the unit.

Burnt Motor

A condenser motor doesn't usually fail all at once. Motor deterioration usually happens over time as the result of poor maintenance and increased stress during operation.

Bad Relay Switch

The relay switch is a critical part of the control board since it's responsible for turning the fan on and off to correspond to the unit's on or off position. If the switch is faulty or fails, the fan can't function properly, and the whole AC unit is unable to do its job.

Damaged Coil

Physical damage to the condenser coil is a surefire way to reduce the overall efficiency of an AC unit. Severe damage may require replacing the full condenser unit. The most common sources of AC condenser coil damage are the following:
  • Impact: Falling rocks or hail can dent or ding the condenser coil.
  • Corrosion: Homes in areas near saltwater, factories or other sources of high pollution are susceptible to early corrosion.
  • Debris: Various sources of debris, like blown yard waste, can clog up or damage a condenser coil.
If the coil itself is damaged, replacement is often a better option than repair.

Repairing an AC Condenser

In many cases, you might need to repair part of your condenser unit. There may be one component failing at a time, or multiple parts may go out at once. You may also experience slow failure of some components while others break suddenly. According to Home Advisor, the cost of repairing an AC condenser ranges from $150 to $600 or more. This is for cases when you are only repairing one or two relatively minor components, such as a circuit breaker. If the condenser motor is the problem, it will cost more to fix due to its complexity. Repairing a condenser motor costs around $350 at the least, up to around $600. If the motor is replaced, you also need to replace the run capacitor to the tune of around $150 to $300. If you have a high-efficiency condenser with a two-stage motor, you are looking at an even bigger price tag. How to Maintain an AC Condenser

How to Maintain an AC Condenser

The best way to ensure the longevity of your AC condenser unit is to schedule regular maintenance, typically twice a year. The main thing an HVAC technician will do is inspect the unit for damage, straighten fins on the unit and use specially formulated condenser coil cleaner to remove dirt that may be impacting the unit's function. While twice a year is a good rule of thumb for maintenance, these factors may make it prudent to request further cleanings.
  • System age: As finishes wear off, older equipment becomes more likely to build up dirt and grime faster.
  • Usage: If you live somewhere hot or simply like a cooler environment, your use may justify extra cleaning due to extra dirt accumulation.
  • Location: Where is your home located? Is there significant construction going on, or are you close to a busy street? These conditions can increase the need for regular maintenance.
Condenser maintenance is not as simple as spraying off the unit with a hose, and you might damage the fins or other components by doing so — especially if you do not use AC condenser cleaner. The best option is to contact air conditioner maintenance professionals and have them do the work for you. You will save time and hassle, and an expert HVAC technician will be able to spot signs of wear and tear or failure in components more easily.

When to Replace Your AC Condenser

An AC condenser unit should last the full life of your HVAC system, which can range from 10 to 20 years depending on factors like the initial brand quality and level of usage. In some circumstances, it makes much more sense to replace the condenser or even the entire AC unit rather than repair the condenser. Below are the two main problems that can't be fixed, which indicate you need a new condenser:
  1. Leaking: With many pieces of machinery, leaks are a relatively simple fix. That is not the case with AC condenser units. Seals and condenser tubes cannot be replaced, so if your condenser springs a leak, you will have to replace the whole coil or possibly even the whole condenser unit.
  2. Blocks: An air conditioning condenser that frequently gets blocked usually indicates that you need a new unit. Having to unblock it multiple times means a larger problem is going on, and it is often more cost-effective to get a new unit.

Other Replacement Considerations

There are reasons aside from leaks and blocks to consider replacing your condenser. Here are the top three to factor into your decision:
  • Age: If your condenser is more than 10 years old, your repair and maintenance costs are only going to keep going up. It may be more cost-effective to just replace the unit.
  • New tech: Today's condenser units are more efficient than ever, which could save significant money over continued repairs in the long run.
  • Older R-22 systems: As of 2020, R-22 refrigerant is banned in the United States. Since you cannot use the newer R-410-A refrigerant in an R-22 system, you would need to replace the entire AC system if yours uses an R-22 refrigerant.
According to Home Advisor, replacing a full AC condenser unit costs between $500 and $3,000, not including labor.

Who Should Replace an AC Condenser?

Replacing a condenser unit or even parts of one is a job best suited to professionals. If you were to make even a simple mistake like bending the fins during cleaning or using a wrong cleaning product, you could cause severe damage to your entire HVAC system. Shop New AC Condensers

When It's Time for a New AC Unit, Think Ingrams Water & Air Equipment

If your AC isn't working the way it used to and you suspect it's time for a new air conditioning system, consider Ingrams Water & Air Equipment. With more than 20 years of expertise in the industry, we are happy to offer HVAC equipment for the best prices. Save time and money and get your new AC shipped right to your door. To learn more about our products and services, take a look at our buying guides and sign up for our newsletter full of tips and specials.
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