How Does a Gas Furnace Work ?
By getting to know how your furnace works, you can have better control of its functioning. Knowing their parts and functioning will give you a better grasp on them and help to repair, replace, or maintain them.
Let’s explore this blog to learn how a gas furnace works.
Different components of Gas Furnaces
Different components of a gas furnace and how they work are:
Thermostat: It is the part that detects the change in temperatures and regulates it conditionally. It maintains the temperature of the furnace according to its set point.
Burners: They are a set of tubes that allow the gas to enter and get burned. It works with other components to control the flames. When the systems call for heat, they all work together to ignite the mixture.
Igniter: This is the device responsible for igniting the gas flames. They create a spark to ignite the gas.
Control Boards: It is a circuit board that controls the functions of the furnace. It interprets various electrical signals and operates the furnace functions accordingly.
Blower fan: This Blower fan is responsible for blowing gas in and out of your furnace and house. Its main function is to rotate the air throughout.
Gas valve: The gas valve receives gas from some external source and controls the flow of the gas.
Heat exchanger: These are either hollow sheets or metal tubes that allow the hot flue gasses to pass through them. The air outside the exchanger absorbs heat from the surface and flows throughout the house.
Flame detector: It is built to avoid gas buildup if the igniter fails.
Air Filter: Most furnaces include some type of filters that clean the coming air. It prevents dust and debris from entering the furnace.
Gas Furnace: Basic Heating Cycle
Let’s start by understanding the heating cycle.
- A basic pipe connected to the LPG enters your house. The LPG-burning units need a storage tank and natural gas needs a connection to the main pipeline.
- Once the gas enters your furnace from the LPG storage tank or gas pipeline, the burner lights it.
- The cold air from your house enters the furnace where it is warmed by it with a heat exchange.
- The exhaust air is pumped out of the house via an exhaust pipe.
- The blower fan pumps the heated air to different parts of the house. The thermostat detects the need for heat.
- The cool air is redirected to the furnace through return ducts when needed.
- Once the desired temperature is reached, it switches off the valve to prevent the backward flow of warm air.
Gas Furnace: Sequence of Operations
The sequence of operations for a gas furnace includes the following steps.
Call for heat
The thermostat sends the signal to the furnace when it reaches a certain temperature set by you. Otherwise, it can remain in a standby mood.
Safety Checks
Before any heating process, you should check the voltage the thermostat is sending to the control board. It should be a 24-volt AC between the W and C terminals. The control boards send 110-125 volts to the draft inducer to start it.
Furnace ignitor
If the inducer rises too fast the valve will be blocked, and the pressure switch will close the connection between the two wires going to the pressure switch. The controller board then sends a signal to the ignitor which glows for some seconds.
Entering of gas
The gas valve opens allowing the gas to flow through the venturi tube and proper combustion begins. The flame sensor will sense the combustion and might turn the ignition off. If the burner does not ignite in 5 to 8 seconds, the controller board turns off the valve.
Relaxed thermostat
When the desired temperature is reached, the thermostat becomes relaxed. The blower motor runs for a prescribed time that the controller board has suggested until the heat is removed from the heat exchanger.
Gas Furnace Safety Tips
- Always keep a check on all the components. Regular maintenance will always prevent big disasters. After knowing all components you must be able to tackle any problem.
- Properly ignite and shut off the gas furnace. This is crucial to timely shut off the gas furnace for safety and efficiency.
- Beware of Carbon Monoxide. You can install Carbon Monoxide detectors to detect its unusual leakage and keep yourself protected.
- Do not take warning signs for granted. If you hear any weird noises or a change in its functioning, seek professional help.
- Keep flammable objects away from the furnace all the time.
- Replace faulty parts whenever you feel like they are not working properly.
- Keep the air filters clean allowing proper ventilation and airflow. Clear any obstructions that come in the way of the flow.
Wrap up
Understanding how a gas furnace operates enhances your ability to maintain, repair, or replace it effectively. Key components include the thermostat, burners, igniter, control board, blower fan, gas valve, heat exchanger, flame detector, and air filter. The heating cycle begins when gas enters the furnace and ignites, heating the incoming cold air, which is then circulated throughout the home. Safety is paramount; regular maintenance, monitoring for carbon monoxide, and addressing unusual noises are crucial. Keeping air filters clean and ensuring proper ventilation also promotes efficiency and safety in furnace operation.
If you are in search of a trusted partner for your gas furnaces then contact Sami James HVAC Services LLC to treat it the right way.
