Delayed Furnace Ignition: Should You Be Worried?

Posted on: November 3, 2020

What does delayed ignition sound like? Is there a reason to worry about the noises your furnace is making?

If your heating system is producing loud and explosive sounds, it’s a natural cause for concern.

Here is some important information about furnace delayed ignition and whether you should reach out to a heating contractor in Riverside to take a look at your heating system.

What does delayed ignition sound like?

When excessive gas builds up in the combustion chamber of your furnace, the delayed ignition will cause a small explosion. This results in a loud bang or boom that can be startling for homeowners. A similar sound can also be caused by expanding and contracting ducts.

What causes delayed ignition on a gas furnace?

You are most likely to notice a delayed ignition when you turn on your furnace, especially if you haven’t used it for a while. This is why delayed ignition usually happens in the fall or late spring when you don’t use it every day.

But why does it happen? In general, furnaces experience delayed ignition because a build-up of corrosion, dust, or sulfur blocks gas-feeding ports and prevents the burners from lighting properly. Here’s how it happens:

Moisture buildup

Over a period of furnace inactivity, moisture tends to build up inside your system, corroding its firebox over time. If the moisture-caused corrosion builds up enough, it can block the ports feeding gas into the furnace burners. If this happens, the burners won’t be able to ignite immediately after you turn the furnace on.

Dust and lint

While moisture and rust are one of the most common causes of delayed ignition in furnaces, dust and lint can also accumulate and cause problems. This can be easily remedied by having your furnace inspected and cleaned by professionals before each heating season.

Sulfur buildup

Your furnace can also experience delayed ignition due to a sulfur build up caused by burning natural gas. If your burners or pilot light are covered in a white layer, you may be dealing with built up sulfur.

Electronic ignition problems

If your furnace has an electronic ignition system, the delayed ignition may be caused by built up combustion gas in the chamber. While your furnace is most likely equipped with a safety mechanism to prevent this, the igniter may not come on promptly and shut off the flow of the gas, causing build-up. If this is the case, you’ll probably have to have the igniter replaced in order to ensure the proper functioning of your furnace.

Is delayed ignition dangerous?

A delayed ignition does not just sound like an explosion, it is one. If you choose to ignore these small gas combustions, it may become quite dangerous.

It may cause damage to your furnace

Unless properly addressed, the delayed ignition explosions are likely to get larger over time. The greater the vibrations are, the higher the chance of the stack pipe getting loose and soot ending up all over your home.

The excess flames caused by delayed ignition can also crack the heat exchanger, one of the most expensive components of your furnace. When this happens, most homeowners choose to replace the furnace instead of replacing the heat exchanger as the latter option is cost-prohibitive and the installation process may result in carbon monoxide leaks.

It may become a safety hazard

Constant gas build-ups in your furnace’s combustion chambers can not only damage your furnace, but may also let the flames out of the chamber and cause a fire. However, modern furnaces are built with mechanisms that uphold high safety standards. Essentially, the risk of explosions and fires will be slim if you properly and regularly maintain your furnace.

How can I prevent delayed ignition on a gas furnace?

Luckily, preventing delayed ignition is not difficult. All it takes is to have experienced HVAC technicians inspect and clean your gas furnace before each heating season, typically in the fall. This will prevent corrosion and dirt from accumulating inside of your furnace and minimize the risks of gas build-up. Here’s how professionals will clean your gas furnace:

  • Cleaning the surfaces: After wiping the exterior surfaces of your furnace with a damp cloth, they will vacuum the furnace base and the burners, as well as clean the dirt and grime from other components.
  • Cleaning the blower: Your technician will carefully clean your furnace’s boiler with a small brush and a vacuum, making sure not to disturb the fan blade counterweights and the wiring.
  • Cleaning the pilot or igniter: Since a dirty pilot light or surface igniter can cause problems with your furnace, your technician will make sure to carefully blow off any dust from these components without damaging them.
  • Cleaning the flame sensors: They will also lightly clean the flame sensor using an appropriate cloth to ensure optimal performance.
  • Lubricating components: When cleaning your furnace, your HVAC technicians will apply a tiny bit of lubricating oil on your furnace’s blower motor and shaft bearings.
  • Replacing the filter: You should have your furnace air filters replaced every 3 months. If you don’t want to bother with this yourself, your HVAC technician will do it for you.

Contact reliable heating contractors in Riverside

What causes delayed ignition on a gas furnace? Most furnace problems can be prevented or eliminated with regular maintenance. If you are searching for a reliable HVAC company in the Riverside area, Action Air Conditioning, Heating & Solar is the optimal choice. We work with a team of skilled NATE-certified technicians who are fully qualified and committed to ensuring your indoor comfort and safety. You can rely on us to help you with all your heating problems, including complex furnace thermostat issues, delayed ignition, and more.

Our services are available across the Riverside area, so feel free to contact us whether you live near Mount Rubidoux or The Galleria at Tyler, reach out for more information!