How Does Central Air Conditioning Work?
Air conditioning is something most of us take for granted, at least until it stops working. Then, the stress sets in because you don’t understand how it works, and fear how much the repairs will cost. Take the stress away by understanding how your unit works, and what you can do to better care for it.
The Role of Refrigerant
The first thing you may think of when it comes to air conditioning is the refrigerant. After all, it is what is responsible for making all that wonderful cool air, right?
The refrigerant works by absorbing heat from the air circulating through your HVAC system. Once it absorbs the heat, it then must vent it to the air outside to keep the cycle going.
To make it work properly, the system must regulate the refrigerant’s pressure as it circulates. When the refrigerant enters the evaporator coil, it must be cooler than the air in order to absorb heat.
To make it cold, there is an expansion valve that restricts the amount of refrigerant in the coil. This restriction decreases the pressure, which in turn makes the refrigerant cold.
In order to then vent the heat outside, the pressure must increase beyond the temperature of the outside air. The compressor is responsible for increasing the pressure before the refrigerant enters the condensing coil.
The Importance of Air Circulation
The refrigerant is what cools the air; however, without the right air circulation, there is no air to cool. Everything about your system depends on air moving not only through your system but also through your home.
In order to properly cool your home, your system must be able to draw in warm air and then push out cool air. The system creates positive pressure at the output vents and negative pressure at the return vents to move the air.
Your HVAC system creates this pressure using the circulating fan. As the fan runs, it draws air into the return vents and through the air filter. The filter is important for removing many airborne contaminants before they create restrictions further in the system.
Then the air flows to the evaporator for it to cool before moving back out into your house. The evaporator coil and circulating fan also tend to collect airborne contaminants. Both of these develop airflow restrictions if not cleaned regularly.
The outside condensing unit must also circulate air to vent the heat from the refrigerant. The condensing fan draws air in through the condensing coils. It then vents the warmed air out the top of the condensing unit.
Any restriction in the airflow prevents the system from cooling properly. It also puts an unusual strain on the system, leading to increased repairs and a shortened service life.
Does Size Really Matter?
Not all air conditioners have the same cooling capacity. BTUs, or British thermal units, are the common measure of cooling capacity. A single BTU is the amount of heat needed to raise one pound of water by one degree Fahrenheit.
The size of your system should match the size of your home and your cooling needs. If your system is too big for your home, it will cause shorter cycles. This prevents your system from having the right dehumidifying effect, leaving your home muggy.
The shorter cycles also mean your system will run more frequently. The start-up process is the most strain your system experiences, so more frequent cycles add considerable wear. This leads to more repairs and shorter service life.
In addition to these, larger systems use more electricity to run. This means that for every minute of running, they are using more power than a smaller-sized system.
However, an undersized unit is just as detrimental because it will constantly run trying to achieve your desired temperature. This is why it is important to get the right size system for your home.
The rule of thumb is 20 BTUs for every serviceable square foot. An experienced HVAC installer will know the other variables to consider, ensuring you’re getting the right size.
What To Expect As It Ages
The average air conditioner lasts 10 to 15 years with regular maintenance. As your system ages, the components will wear out and may need replacing. Reduced efficiency is the other common issue you’ll encounter.
Preventable airflow restrictions cause most of the efficiency declines in older systems. Regular maintenance will help you avoid most of these restrictions.
Maintaining Your System
There are two primary things you can do to help keep your system running well through its entire service life. First and foremost is changing your air filter regularly.
Most systems should have a new filter about every 90 days. However, your air quality and specific filter type will determine how often you should change your filter. Consider checking it monthly so that you can see how quickly it gets dirty and needs replacing.
The next most important thing is having professional routine maintenance every spring. Most manufacturers understand how important this maintenance is, so they require it to keep their warranty valid.
During a maintenance visit, a technician does a series of tasks to help improve efficiency and find minor problems. This includes cleaning the coils and circulating fan and testing the refrigerant level. They will also test each individual component to ensure they are operating optimally.
Catching small problems early and correcting them prevents more costly repairs. Larger problems also cause more problems to develop because of the strain they put on the system.
Problems You May Encounter
Your system will give you some indications when there is a problem if you understand how to interpret the signs. These signs may be in the form of unusual sounds or performance issues.
Anytime you have a problem with your air conditioner, start by checking to make sure the air filter is clean. Again, catching this early can prevent many other problems caused by too little air movement.
You may have problems with your circulating fan motor burning out. This is common, being this fan serves both the air conditioner and heating system. You will likely notice an issue of the fan turning slowly or not starting, and you may notice a squealing sound.
There are also two electrical controls in the condensing unit that tend to need replacing before the entire system. The contractor is the switch that controls the electrical current going to the compressor. When this goes bad, you may notice a chattering sound, which is the contractor opening and closing quickly.
There is also a capacitor in the outside condensing unit. This holds a large electrical charge to start the compressor. When this goes bad, you may notice the compressor failing to start and a loud humming sound.
The last common issue is a refrigerant leak in the system. Larger leaks may have a hissing or screaming sound. You may also notice parts of your system freezing if there is a leak due to insufficient refrigerant.
Due to the large electrical current powering your air conditioner, leave repairs to a professional technician. They have the right tools and training to find the root problem and solve it safely.
Contact We Care Today
We Care Plumbing, Heating and Air has provided expert service to residents and businesses around Murrieta for more than 20 years. Our customers trust us for heating and cooling installation, repair, and maintenance along with a variety of plumbing needs. Contact us to schedule your air conditioning consultation with one of our expert technicians today.