Why There's A Tiny Blinking Red Light On Your Furnace

It's easy to forget all about your furnace until you start shivering on a cold morning. While there are several possible reasons your furnace stops turning on, sometimes the problem is harder to pinpoint. Although you won't find one on every unit, one of the first things you may notice is a tiny red blinking light on your furnace. According to Matt Gorbacz, Owner of Clean Air Technologies and HVAC System Cleaning expert, the diagnostic light may be trying to tell you something important ... but it isn't always a reason to panic.

"The light itself isn't a problem, but the pattern of blinking is," Gorbacz said during an exclusive interview with Hunker. "Different furnace manufacturers use different diagnostic codes, so one should check the panel or the furnace manual to see what that particular blink pattern means." If you can't find it anywhere, try doing a quick Google search for the manual. Somewhere in the troubleshooting section, you're likely to find a detailed key that can help you diagnose the problem.

"In most cases, the light is simply telling you that the furnace has power and is operating normally," Gorbacz said. Of course, that won't be the answer if you've got the heat cranked up and it's still cold inside. In that case, you may need help deciphering the blinking pattern because, as the expert put it, "Sometimes a specific number of flashes can point to a problem with ignition, airflow, a safety switch, or another component."

Once you've stopped wondering why there's a tiny blinking red light on your furnace, you'll probably begin wondering what exactly you should do about it. Although it isn't a sure sign your home's heating system is going to break down this winter, Gorbacz told Hunker there are a few things homeowners can safely check before calling in professional help. "They can start with the air filter. If it's dirty, replace it with the correct size and type," the HVAC system cleaning expert said during his exclusive interview. Clogs from dust, pet hair, and other debris can cause more problems than you might realize. "A clogged filter can restrict airflow and cause the furnace to overheat or trip a safety switch," Gorbacz said.

There are other basic checks you can do after catching your furnace's little red light blinking like crazy. In addition to double-checking your thermostat settings, Gorbacz says to make sure your vents aren't being blocked by furniture or other items. Sometimes, more than one service call has been made only for a professional to simply flip a furnace switch that's been accidentally turned off.

Nevertheless, you should think twice before trying to handle a major furnace repair yourself. "I wouldn't recommend doing anything beyond these basic checks if you're just seeing a blinking light," Gorbacz cautioned. "If the furnace isn't heating, keeps shutting off, or the diagnostic light continues to blink, it's best to have a professional look at it."

To avoid the dread that starts to set in the second you spot that blinking red light, Gorbacz told Hunker there's one thing homeowners must remember. "For furnace maintenance, the biggest thing one can do is stay on top of the basics," he explained during his exclusive interview. In addition to keeping the area around your furnace clear and avoiding blocked vents, it's also important to do a little sleuthing when something seems off. "Pay attention to changes in how the system operates. If the furnace starts making unusual noises, cycles on and off more frequently, or takes longer to heat the house, get it checked by a professional," Gorbacz recommended.

That may leave you wondering exactly what to expect from a furnace tune-up. HVAC professionals will start by checking your system for leaks, condensation, and rust. They'll also take a look at all the wiring connections, the pilot light, and valves before testing your thermostat. And, yes, they'll take a look at that tiny blinking red light on your furnace to see if its flashing pattern is indicating a problem that needs to be fixed.

"I recommend getting the furnace professionally serviced at least once a year, ideally before the heating system begins," Gorbacz said. The HVAC system cleaning expert also suggested scheduling another visit once you're ready to switch back to cooling. According to Angi, the cost for a professional HVAC maintenance service ranges from $175 to $350 depending on the type of system and time of year.