blue furnace flame

Heater Behavior: What’s Normal and What’s Not

Have you ever looked at or listened to your heater and wondered, “Should it be acting like this?” The good news is that you don’t have to be a heating and cooling expert to learn some essentials about heater behavior. Below, we’re going to look at some of the top inquiries we get from homeowners about their heating systems, and we’ll tell you what’s normal and when you should contact a technician.

The heater is taking a while to “warm up.”

If your heater turns on after being shut off for a long time, it might take a few minutes for the air coming out of your vents to warm up. Even if your heater working just fine, the air still has to travel through cold ductwork before it gets to each room, and it can lose heat along the way.

If the air never warms up at all, make sure your thermostat is set to AUTO (not ON), and check to see if your system needs a new air filter. You’d be amazed how often one of these steps solves the issue! If neither of these troubleshooting tricks works, it’s time to call a technician.

The heater makes a boom or banging noise whenever it starts up.

Right away, any HVAC expert will tell you that this a problem, and they’re right. You’re hearing this noise because your furnace has an issue with delayed ignition.

Here is what happens:

  1. Your thermostat signals your furnace to start a heating cycle.
  2. Your furnace “feeds” a gas and oxygen mixture to the burners so that they’ll ignite--but something is preventing that ignition from happening.
  3. Consequently, the gas mixture starts to build up.
  4. Finally, when the gas mixture ignites, it makes a small explosion inside your furnace’s combustion chamber--boom!

Over time, these mini-explosions can damage your furnace, and any excess gas can be dangerous because of how volatile it is. In some cases, this problem can be solved by cleaning the burners. However, there could also be an issue with the ratio of gas and oxygen in the gas mixture. It’s best to involve a technician to get to the root cause of the problem.

The heater is giving off a strange smell.

If you smell something burning when you first turn your heater on for the season, don’t be alarmed. This is most likely just dust burning off in the equipment. If this smell doesn’t go away, then you should shut your system off and call a technician.

Your heater should never give off odors that smell like any of the following:

  • Burning rubber
  • Burning oil
  • Melting plastic
  • Overheated metal
  • Garbage or something rotten
  • Mold or mildew
  • Natural gas, sulfur, or rotten eggs

Bad smells can signal anything from a mechanical problem to a gas leak to a dead animal trapped in your ductwork. These scenarios are best handled by a professional.

The heater is making a loud humming noise while it runs.

While no heater runs completely silently, the unit shouldn’t start making a humming or buzzing noise out of the blue. Humming can indicate the need to replace a part, such as a failing capacitor or blower motor, but typically, these types of noises mean that the equipment just needs a little maintenance. As the system goes through wear and tear, parts can loosen, and the blower motor can lose lubrication. Technicians can easily take care of issues like loose parts or lack of lubrication during a maintenance appointment.

The furnace flame has some yellow and orange in it.

Your furnace flame should be bright blue, but it is also okay if the very tip is yellow. If you’re seeing streaks of yellow, orange, red, or green in the flame, then you know there’s a problem.

Why does the color of the flame matter? There are two significant reasons:

  • If the flame isn’t pure blue, then your furnace isn’t burning as hotly or efficiently as it should be. This means that your furnace is costing you more money to use than necessary.
  • Yellow and orange flames also mean that the fuel isn’t burning as “cleanly” and that more pollutants (including carbon monoxide) are being released during the combustion process).

Dirty burners are the most common culprit behind yellow and orange furnace flames. If cleaning the burners doesn’t solve the problem, or if you don’t know how to clean them correctly, an HVAC technician can perform this task for you. There could also be too little oxygen in the gas and oxygen mixture that’s fed to the burners. You will definitely need a technician’s help to handle this issue safely.

At Bounds Heating & Air, we pride ourselves on top quality heater repairs and unmatched customer care. To schedule heating service in Gainesville, call (352) 290-3370 or send us a message online.