HVAC Diagrams: An Overview of Your HVAC System Components

January 16, 2023
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Like many consumers, you probably know very little about the HVAC system in your Roseville, MO, home. However, learning about the different components that this system is comprised of will make it easy to identify, troubleshoot, and prevent issues. Following is a comprehensive overview of a standard HVAC diagram and all that it includes.

Quick Tips for Making Sense of a Standard HVAC Diagram

Accessing a standard HVAC diagram online will give you a clear and simplified view of an HVAC system’s main parts. However, whether using diagrams to better understand your system or maintain it, it’s important to remember that actual schematics can vary greatly from one home to the next. Many Roseville homes have a number of integrated HVAC system accessories, including:

  • Media filters
  • Air scrubbers
  • Air purifiers
  • Humidification/dehumidification equipment

Older homes can have significantly different HVAC system layouts from newer properties. For instance, if your HVAC system hasn’t been upgraded in many years, it may have fewer components or it may have components
that have been replaced by more efficient and modern designs. Some homes have central HVAC systems that have been zoned for efficiency, and others have two separate heating and cooling systems to accommodate multiple floors.

In general, nearly all HVAC system diagrams will include a heater, an air conditioner, and a complex system of HVAC air ducts. Detailed diagrams will break each heating and cooling unit down into its most significant parts, and they will explain how these parts are connected to the others.

A Breakdown of Your Home Cooling Equipment

Air conditioners have indoor and outdoor units. The indoor unit includes the:

  • Evaporator Coil
  • Blower
  • AC filter

An air conditioner’s evaporator coil absorbs heat from the indoor air, and the blower fan keeps this air moving. The AC filter is a semi-permeable barrier that allows air to flow through but keeps large-sized particulates out. Designed primarily to prevent dust, dirt, pet dander, and other debris from coating the interior of your cooling equipment, this component should be checked once each month. In most households, AC filters should be changed about once every one to three months.

The AC component at the exterior of the building is called its condenser. The primary components within an AC condenser are the:

  • Condenser coil
  • Compressor
  • Fan

The AC condenser’s fan is visible beneath the condenser cover. There is a large-sized grille where the fan is located that provides adequate ventilation. When the air conditioner is in use, the condenser fan blades rotate to draw outdoor air in. This air is then filtered, cooled, and distributed throughout your home.

The condenser coil is a critical component in an air conditioner’s heat exchange process. After the refrigerant in your air conditioner has absorbed heat from the indoor air, the condenser converts it from a gas into a liquid and then releases hot air outside.

An air conditioner’s indoor and outdoor units are connected by a refrigerant line. The coolant that flows through this line is the lifeblood of the heat transfer process.

Forced-Air, Gas-Fired Heating Units

The most common heater type in forced-air heating systems is the gas-fired furnace. Often located in basements, garages, closets, or utility rooms, gas-fired furnaces have:

  • Air Filters
  • Blower motors
  • Return and supply plenums
  • Venting systems
  • Electric ignition switches
  • Burners
  • Flame sensors
  • Heat exchangers

All fuel-burning appliances release exhaust gases like carbon monoxide. These are produced as the result of incomplete fuel combustion. To keep building residents safe, these heating systems have direct venting that releases their emissions outdoors.

Furnace air filters are primarily designed for the protection of furnaces themselves. Letting these components become coated in dirt, dust, lint, and other grime can cause the unit to overheat. Thus, much like AC filters, furnace air filters should be checked once each month and changed once every one to three months.

Electric ignition switches have replaced the pilot lights found in older gas furnaces. As such, even though gas-fired furnaces use natural gas as their heating fuel, they still require electricity to power them. The burners in your furnace are what combust the fuel that’s used to heat your home. Heat exchanges are the components that transfer the heat that’s produced by fuel combustion into a usable, distributable form. Some furnaces have just one heat exchanger. However, many new, high-efficiency furnaces have two.

Flame sensors, thermocouples, and other related components play a hand in moderating the production, routing, and venting of exhaust gases among other things. When even one of these components malfunctions, gas furnaces won’t turn on as a preventative measure.

Heat Pumps in HVAC Systems and Their Dual-Functionality

Some homes don’t have furnaces and air conditioners in their HVAC systems. Due to their efficiency, heat pumps are fast becoming a top choice for both residential heating and cooling. Rather than combusting fuel to heat homes up, these units simply transfer heat. They function much like air conditioners and have many of the same parts. One of the primary differences between heat pumps and AC units is the fact that heat pumps can work in reverse. This makes these units acceptable as standalone, year-round heating and cooling solutions in many areas. Like AC condensers, heat pumps or heat pump condensers are located outside.

What Your HVAC Air Ducts Include

HVAC air ducts are a vital part of HVAC systems. They’re the channels by which heated and cooled air are distributed throughout the building. The HVAC air ducts are where many integrated HVAC accessories are installed, and they’re also usually where you’ll find a furnace’s return and supply plenums.

HVAC air ducts include:

  • An air handler
  • The actual air ducts
  • Dampers
  • Bypass ducts

Air handlers are typically found in low-lying areas of the home such as the basement, or you may find this component in the garage. This unit regulates the return and supply of air throughout the home. The air ducts or air duct supply is a network of ducting that travels throughout the entire building. Each duct is connected to an air vent or grille where heated or cooled air flows out. Dampers are components that control the flow of air. Dampers or bypass dampers can be manually or automatically sealed shut when you want to keep air out of select areas.

Frequently used in zoned heating and cooling systems, bypass ducts are air ducts that are specifically designed to relieve excess air pressure. For instance, if you close an HVAC damper, excess pressure will build within the entire system. When needed, a bypass damper will open up to let this excess air flow out and restore system balance.

Need an HVAC Service?

With timely attention given to developing problems, Roseville residents can prolong the lifespan of their HVAC systems, ensure optimum levels of efficiency, and cut their costs. C & C Heating & Air Conditioning is committed to helping our clients achieve these and many other home comfort goals. We offer air conditioner and furnace maintenance, installation, and repair services. We also offer ductless heating and cooling systems, HVAC air duct cleaning, and indoor air quality control. We’ve proudly served the area since 1948, and we strive to offer exceptional service from start to finish. If you need help keeping your HVAC system in top condition, give C & C Heating & Air Conditioning a call today.

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