Your HVAC System’s Most Critical Components

Your heating, ventilation, and air conditioning (HVAC) system is made up of many different parts. You may have heard of some of them, while others may be a mystery to you. Understanding how the most important HVAC components work will help you identify when your HVAC system has a problem. Below are the most critical components of your system and how they operate within it.

Visible Components

These are the HVAC parts you may be most familiar with. They are built into the building and connected to the HVAC system, and they are at least somewhat visible. These components carry the heated or cooled air between the system and the building’s rooms and hallways.

Thermostat

The thermostat is usually your system’s most visible component, and it is wired directly to your HVAC system. It has temperature sensors that turn on the heater or air conditioner based on the conditions in the building, room, or zone it heats or cools. You can install a programmable thermostat that allows you to set its temperatures in advance or control it manually. 

Additionally, you can use your thermostat to make your system more energy efficient. When you leave the building, lower the temperature only a few degrees in winter and raise it a couple of degrees in summer. This will reduce the amount of energy your HVAC system consumes when no one is using it. You can use remote thermostat controls to adjust the temperature back to its normal settings before you return.

Ductwork

Your building’s ductwork is the system of ducts that connect back to your HVAC unit or system. It carries the warm or cool air from the system out to the rest of the building. Ducts are often made of steel, but they can also be made from other materials, including fabric, fiberglass, polyurethane, and aluminum.

Registers, Grilles, & Diffusers

Registers, grilles, and diffusers are where the ductwork system meets a room or hallway. They can be round, square, or rectangular and are covered with angled slats that can be closed manually or controlled to change the airflow to a particular room. Registers, grilles, and diffusers can be made of temperature-safe metal, wood, or plastic.

Hidden Components

These are the HVAC system components you often cannot see, but that are critical for heating and cooling air within the system. Without these parts, the ducts and vents have nothing to carry to the rest of the building.

Condenser Coil and Compressor

The condenser coil and compressor are the parts of your air conditioner or heat pump that move and condense refrigerant to cool the building and release heat outside. A fan blows over the coil while the compressor pumps the refrigerant to release the captured heat more quickly. After the refrigerant is cooled and condensed, it travels through the refrigerant lines. These components are typically part of your HVAC system’s condensing unit, which is usually outside the building. 

You can maintain your condensing unit by annually clearing debris away from it and cleaning it off with a hose, or more often if necessary.

Refrigerant Lines

Refrigerant lines are copper tubes that carry refrigerant between the condensing unit and the evaporator coil. They carry superheated refrigerant vapor to the condensing unit where it is subcooled and delivered in liquid form to the evaporator. The liquid refrigerant is forced through a metering device installed between the refrigerant lines and the evaporator coil. This metering device lowers the pressure and subsequently the temperature of the refrigerant allowing it to flow into the coil for the absorption of heat.

Evaporator Coil

The evaporator coil is within your HVAC system’s indoor air handler. It receives liquid refrigerant from the condenser, and it uses warm air in the space to turn the refrigerant back into a gas. This process restarts the cooling cycle, so the refrigerant lines can carry the gas back to the condenser to be cooled and liquefied again.

Monitor your evaporator coil for mold growth and dust and dirt buildup, as well as ice caused by low pressures/temperatures. This could be an indicator of various system issues. If your HVAC system is not properly maintained, these problems can lead to breakdowns and expensive repairs.

Heat Exchanger

This component is present with fossil fuel burning heaters. The unit will burn the fuel and reject the products of combustion through the heat exchanger. This is basically an exhaust pipe reshaped to fit within the heaters casing. The cool air from the space is blown across it and it is heated by contacting the hot metal tubing. This tubing is consistently stressed with the acidic exhaust gases inside and the rapid heating and cooling of the metal.

Make sure your heat exchanger is properly inspected annually. If it isn’t, it could develop carbon monoxide leaks, which can cause headaches and nausea, and even lead to death. Installing carbon monoxide detectors around your office is recommended since carbon monoxide can’t be seen or smelled.

Combustion Chamber

The combustion chamber is the part of the furnace that combines oxygen with fuel. The fuel type depends on what kind of furnace or heating system you have. If you have a gas furnace, for instance, the fuel will be gas. Then either a pilot light, glow plug, or sparker ignites the fuel and oxygen mixture to create a controlled fire that is drawn through the heat exchanger.

A pilot light is a small flame that constantly burns fuel at the combustion chamber to light the main flame on a call for heat. It is found mostly in older heating systems. If it goes out, you may smell gas and a competent person must relight it. Glow plugs and sparkers, however, are electric ignition systems that light automatically. They are found in newer systems.

If you have an older heating system that contains a pilot leak, monitor it carefully. If the pilot light goes out, it will likely release gas into your building, which will cause major safety risks. 

Maintain Your HVAC Components With Us

At Service Unlimited, we provide preventive HVAC maintenance that will keep your system’s components in good working order. If you have any questions about our maintenance services, contact us today. We want to make sure your system produces conditioned air safely and efficiently.

1 reply
  1. Mindy Jollie
    Mindy Jollie says:

    I appreciate your explanation of how the thermostat works and how it interacts with a house’s HVAC system. My house has been having issues maintaining an even temperature, at least aside from the main floor. I’ll have to make sure to find a professional to come to check it out and possibly make some repairs. Maybe the thermostat is the issue!

    Reply

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