Humans and the shelters we build are inseparable. Some researchers argue that we’ve built hearths for 1.5 million years–nearly as long as our species has been around.
Hearths and woodburning stoves may be less common these days, but the general idea has remained the same. In the modern era, we use furnaces to keep warm and comfortable. With modern solutions, though, come modern problems: a broken furnace is much more difficult to repair than a hearth.
Knowing the parts of a furnace system better prepares you for when they break down. Read on as we discuss the most common components in your residential HVAC system.
Ignition Parts of a Furnace System
A gas furnace, in its simplest form, burns natural gas to heat air to acceptable temperatures. Of course, natural gas can explode if you mishandle it. Safe ignition is key to running it without risk to the residents.
Let’s discuss the lighting systems that a gas furnace employs.
Pilot Light
A pilot light is a device that uses a controlled spark to ignite gas passing through the burners.
You will find pilot lights everywhere, from your water heater to your stovetop. They are a critical component in almost all heating and cooling systems. It’s only with air conditioner repair that you won’t need to replace one.
A pilot light is usually one of the first components to go. Fortunately, they are easy to swap out without ripping out the entire system in the process. Call HVAC services for a quick and easy replacement.
Hot Surface Ignitor (HSI)
Pilot lights are one method for igniting the gas in a furnace. Another, which is also reliable and inexpensive, is the HSI–hot surface ignitor.
Pilot lights use a spark to do their work. An HSI, on the other hand, heats an element until it glows orange–hot enough to ignite. As the gas passes through, it catches fire.
Detector Parts of a Furnace System
Lighting the furnace is only one part of the equation. As the furnace is burning, it needs to keep a close watch over the heat passing through the system. Detectors do the job.
Thermocouple
Suppose the pilot light works as intended. How does the system detect that it is burning properly? That’s where the thermocouple comes in.
In essence, a thermocouple is a temperature sensor. When it detects heat created by the pilot light, it communicates that to the circuit board and gas valve. Without the thermocouple’s go-ahead, the system may fail to run.
Flame Sensor
Thermocouples are effective and reliable, but they are an older technology. A cheaper and more efficient modern alternative is the flame sensor.
They are much smaller, but perform the same task: they detect heat. Without their approval, just as a thermocouple, the system will fail to start.
Gas Modulation Parts of a Furnace System
Natural gas, when you burn it at the right temperature, is safe and effective. In the wrong conditions, though, it can and will detonate. Special components in a furnace regulate the gas carefully throughout the system.
Gas Valve
The gas valve has two main responsibilities. Number one, it provides a controlled flow of gas into the system. Number two, it controls the pressure of the gas as well.
There are more advanced, more efficient versions of a gas valve. For example, a modulating gas valve or a two-stage gas valve. Both can deliver precision-controlled amounts for better burner efficiency.
Gas Burner
You can see an example of a gas burner on your stovetop. All it is is a series of metal funnels that direct gas to where it will burn. Thanks to the fact that there are no mechanical parts, it’s highly unlikely to fail.
Like a stovetop, it burns constantly to heat the air. The pilot light ignites it, and the detectors ensure it’s working.
Heat Exchanger
Of course, you can’t just have an open flame to heat the air. That would be dangerous and inefficient. You would end up breathing in exhaust fumes rather than clean, heated air.
That’s where the heat exchanger comes in. Think of it as the barrier between the flame and the air that you want to heat. Usually, a heat exchanger is a series of pipes that passes air over the burner.
More efficient systems include a secondary heat exchanger to collect residual heat. This ensures that no heat goes to waste in the closed-loop system.
Draft Inducer Motor
Even if the exhaust won’t end up in your lungs, it needs to go somewhere. A draft inducer motor aids in the exhaust process. It channels toxic carbon monoxide and other flue chemicals out of your home.
It takes those nasty chemicals and vents them into the open air. This allows them to disperse into the atmosphere, where they no longer cause any harm.
However, you should still have a detector in the furnace room. A monoxide detector should usually be sufficient.
Other Parts of a Furnace System
We’ve covered all the major components that every furnace system needs. Let’s discuss some of the lesser known–but equally important–parts.
Control Fuse
Every high-voltage device requires a fuse. This is a barrier that protects delicate circuit boards against surges. Similar to automotive fuses, they prevent overloads that could kill expensive parts.
Zone or Airflow Damper
Think of these as control mechanisms for airflow. They can stop airflow or redirect it to where your home needs it at the current moment.
Understand Your Furnace Brand Better
All the parts of a furnace system play critical roles in safe, efficient operation. Something as simple as a pilot light failure can stop the entire thing from operating. When you call your HVAC services, the replacement of one of these parts may be all you need to get the furnace running again.
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