People sometimes needlessly worry about the safety of gas furnaces. It’s true that any gas-powered system can become hazardous due to combustion dangers and the release of toxic gases like carbon monoxide. However, gas furnaces are built to rigorous safety standards that lower the chance of dangers occurring. If gas furnaces weren’t generally safe, they would never be permitted in homes in the first place.

This safety does come with a few caveats. For a furnace to run at its safest, it must have annual maintenance, and any malfunction requires a prompt response from professionals. We offer furnace repair in Greenwood, IN as well as regular maintenance because not only is your comfort Vital, but so is your safety.

If you’d like to know more about the parts of your gas furnace that keep it running safely, follow us below.

A gas furnace work by burning the natural gas that comes from the burners. An electronic ignition system lights the burners, and the heat from the burners is then drawn into a heat exchanger, which transfers that heat to the air. The flames from the burners should remain inside the firebox. If the flames cannot access enough oxygen to remain lit, they’ll expand outside the firebox to reach it, a dangerous situation called “flame rollout.” The flame rollout switch detects when this happens and immediately shuts off the flow of gas to the burners.

You don’t want your furnace to overheat, and the limit switch is designed to prevent this. The limit switch triggers when the heat exchanger becomes too hot. This can mean that not enough air is moving around the exchanger to cool it off (this can happen if the air filter is clogged) or the exchanger isn’t venting properly. Whatever the cause, the limit switch will prevent further damage.

When the furnace begins a heating cycle, the control board opens a gas valve to send natural gas to the burners, then signals to the electronic ignition system to light the gas. However, if the ignition system fails, unburned gas will continue to flood into the combustion chamber, which creates a risk of an explosion. To stop this, a device called the flame sensor monitors if the burners have ignited. If it doesn’t detect flames, it will send a signal that shuts off the gas valve and ends the flow of gas to the burners. Older furnaces used a similar device called a thermocouple to do the same job. 

One of the ways a furnace gas can allow toxic gases into a home is if its flue becomes blocked. The flue allows the combustion byproducts in the heat exchanger to escape from the furnace and the house. A blocked flue will start to push gas back into the furnace and eventually into the home. The pressure sensor registers if the inducer motor that draws exhaust gas into the flue is operating correctly. A pressure change means exhaust flowing the wrong way, in which case the sensor will shut down the entire furnace. 

If the safety features in your furnace start to activate, please call our technicians as soon as possible to see what needs repairs. 

Call Vital Heating & Air because “Your Comfort Is Vital!”