What Does the Blinking Light on my Furnace Mean?

Furnaces are complicated machines. Sometimes it’s not clear what’s wrong with them, especially when the only indicator it’s giving you is a blinking light. Decoding the meaning behind the blinking light can be a bit tricky but thankfully it usually isn’t as bad as it seems.

Here at Ball Heating and AC, we are experts when it comes to furnaces. Here are a few reasons behind the blinking light on your furnace.

What Does the Blinking Light Mean?

New furnaces come with a few lights to send signals to the user to let them know how the machine is running. If the furnace is making a strange noise, not creating heat or admitting a strange smell, then you know something is wrong. Seeing a flashing light on your furnace is another, more subtle way, to let you know something is wrong with your furnace. 

The blinking light acts as a sort of morse code, where different kinds of blinking mean different things. On some furnaces, they will have the codes written down on the furnace itself but they will almost always have them in the user manual. 

Why is the Light on My Furnace Blinking? 

Even with the manual, it can be difficult to interpret what the different kinds of flashing mean. Here are a few things the blinking light could mean.

Blower Running After Power Up

If you power on your furnace for the first time in a while, the blower might take a bit longer than normal, causing the light to blink. This is normal and the furnace should continue to power up as normal and the light will stop blinking.

Furnace Lockout

A furnace lockout occurs when the furnace is failing to ignite. Resetting the furnace by cutting the power to the furnace at the breaker can fix it. Leave it off for a few minutes and then try turning it back on again. If it still is not igniting, call a professional to examine it.

High Temperature Detected

The high limit switch and roll-out switch detect heat inside the heat exchanger. If they detect a high heat they will activate the fan. These switches are all over the inside of the furnace to properly detect the heat levels. If it detects a very high temperature, the light should start blinking. Replacing the furnace filter could resolve the issue but if it doesn’t, call an HVAC technician to have it examined further. 

Pressure Switch Failure

The pressure makes sure the furnace is venting any unwanted gas. If this switch fails then the light should start blinking. Fixing this is very complex and should be left to a professional. 

Gas, Ignition Failure or Proving Fault

Errors with the gas, ignition failure, or flame proving failure might be the reason behind your blinking light. This could be an indicator your flame sensor is dirty, and cleaning it should fix it. However, this could also mean there is a problem with the gas valve or ignitors. Call an HVAC professional to resolve this issue.

If you need help with your furnace, don’t hesitate to call the pros at Ball Heating and AC. Whether you need help with an AC tune-up, a furnace installation, or an air quality check, we can help you with all your heating and air needs. If you are located in Biloxi, Mississippi, contact us today!