Even though you rely heavily on your HVAC system to keep you comfortable throughout the year, you might not know all that much about how it works. That’s not unusual. Most homeowners’ knowledge of HVAC systems doesn’t go much beyond operating a thermostat. However, if a component of your Hanover, MD home’s HVAC fails, a bit more knowledge can go a long way toward getting you back on track. To help, here is a guide to the major components of your home’s HVAC system. We’ll identify each component and let you know exactly what it does. That way, you can approach future necessary HVAC repairs with confidence that you know what you’re talking about.
Thermostat
We’ll begin with the part of your HVAC that you’re most familiar with. Your thermostat is the device that keeps track of the temperature in your home. It also signals your HVAC system to turn on and off based on your comfort preferences. Your thermostat connects to your HVAC system via control wires. A basic thermostat will have at least four wires connecting it to your HVAC. More advanced thermostats, including smart thermostats, can have up to six wires.
You can think of your thermostat as the brain of your HVAC. The more advanced your thermostat, the more you can do with your HVAC system. Basic thermostats have little more than simple temperature sensing and on/off capabilities. Programmable thermostats make it possible to set automated temperature schedules by the day or hour. Smart thermostats feature advanced connectivity and learning capabilities to maximize HVAC efficiency and improve your comfort.
HVAC Indoor Unit
The parts contained inside your HVAC’s indoor unit vary depending on the type of system you have. For these purposes, we’ll assume you have a combination of a gas furnace and a central AC system. These are the parts you’ll find in the indoor unit of such a system.
Control Board
The control board inside your HVAC indoor unit receives signals from your thermostat and activates components as necessary. If you request heat, it will activate your furnace’s burners and blower motor to provide it. If you need cooling, your outdoor condenser unit and indoor unit blower motor will activate.
Blower Motor
The blower motor in your HVAC indoor unit draws in air through your home’s return air ducts. It pushes that air past the system’s heat exchanger or evaporator coil to heat or cool it as needed. Then, it pushes the conditioned air back through your home’s supply vents.
Combustion Chamber and Burners
The combustion chambers and burners inside your HVAC indoor unit are the main components of your furnace. Inside the combustion chamber, there’s a valve that controls the flow of natural gas into the burners. It ensures that there’s a proper mixture of gas and oxygen to support complete combustion inside the chamber. To ignite the combustion process, the burners typically rely either on a pilot light or a glow stick. The pilot light continuously burns a tiny amount of natural gas to serve as an ignition point. A glow stick uses electrical resistance to create enough heat to cause combustion of the gas and air mixture.
Heat Exchanger
Your heat exchanger is the part of your furnace that warms the air coming from the blower motor. It is like a radiator. The hot gasses resulting from the combustion process pass through sealed tubes within the heat exchanger. Those tubes have large sets of fins attached to them, which transmit the heat into the passing air. Then, the combustion gasses leave the heat exchanger to exit your home through the furnace’s flue.
Flue
Your furnace’s flue is a pipe that allows the furnace’s combustion gasses to leave your home safely. These gasses include substances like carbon monoxide, so proper ventilation is critical. Those combustion gasses also leave the heat exchanger at a high temperature. Furnace flues are typically made of aluminum, which can handle high heat without warping or suffering damage.
Evaporator Coil
When you’re running your HVAC in cooling mode, all the previously mentioned furnace parts stand idle. The only shared component that doesn’t is the blower motor, which runs in heating and cooling mode. However, in cooling mode, another type of heat exchanger called an evaporator coil goes to work. The evaporator coil receives cold refrigerant from your HVAC’s outdoor unit. As air passes over the coil, the cold refrigerant absorbs heat from the air to cool down your home. That causes the refrigerant to warm up and boil off into a gas before it leaves to return to the outdoor unit. The process of cooling the air also allows your evaporator to dehumidify the air through condensation. The collected water then drains from your indoor unit via a condensate drain line.
HVAC Outdoor Unit
Your HVAC outdoor unit is only active when you’re running your system in cooling mode. As a result, it has fewer parts than the indoor unit. Here’s what they are.
Compressor
As its name suggests, the compressor in your HVAC outdoor unit manipulates the pressure on the system’s refrigerant. Specifically, it increases the pressure on the warm gaseous refrigerant coming from the system’s evaporator coil. This raises the temperature of the refrigerant until it’s hotter than the outside air. That’s how your HVAC system can exhaust heat from your home even when it’s hot outside.
Condenser Coil
The majority of the space in your HVAC outdoor unit is occupied by a heat exchanger called a condenser coil. It’s where the hot, high-pressure refrigerant goes to release its heat into the outside air. To facilitate that, the condenser coil has a series of large fins to maximize contact with the outside air. The condenser coil gets its name from the process that happens inside it. As the hot gaseous refrigerant releases its heat, it condenses back into a liquid to begin the cooling process again.
Condenser Fan
A large fan called a condenser fan is typically situated at the top of your outdoor HVAC unit. Its job is to pull outdoor air through the fins of the condenser coil to cool the refrigerant inside it. The fan vents air straight up from the top of the unit.
Expansion Valve
After the cooled refrigerant condenses back into a liquid, it’s still too hot to help cool your home. That’s where your outdoor HVAC unit’s expansion valve comes into play. It reduces the pressure on the warm liquid refrigerant. This lowers the refrigerant’s temperature and its boiling point. At that point, it can travel back to your indoor unit to begin the cooling process again.
Your Local HVAC Experts
For over a decade, Beltway Air Conditioning, Heating, & Plumbing has been the leading HVAC company in Hanover. We offer complete HVAC installation, repair, and maintenance services. We also offer plumbing, indoor air quality, and ductwork services. We even handle commercial HVAC systems if you also own a nearby business. Our team of expert HVAC technicians and plumbers can be your best ally in keeping your home’s major infrastructure running. We even offer financing options on approved credit to help you pay for larger HVAC projects. Plus we’re Better Business Bureau accredited with an A+ rating. If you need HVAC services in Hanover, call our team at Beltway Air Conditioning, Heating, & Plumbing today!
