How do you fix a blinking red light on a furnace?

HVAC | January 13, 2022

What Does The Blinking Red Light on My Furnace Mean?

You can tell something isn't right with your furnace. You go to your furnace and that's when you notice it - the blinking red light.

Typically you would see a solid amber or yellow light, indicating everything is fine and your furnace is in good working order. However, if you notice that the furnace light is blinking red multiple times, it's an indication that something isn't right with your system and furnace repair service could be in your future.

Whether it is your blower motor or a flame sensor, if left unaddressed it could lead to failure of the heating system and major damage inside your home.

This is the way your furnace talks to you. Think of it like a Morse code. Depending on the brand you have installed in your home, such as a Trane furnace or a Carrier furnace for example, and the frequency of flashes from this light, you can easily understand the corresponding error your furnace is telling you.

Now you just need to figure out what the flashing light means and crack the code.

In this article, we'll help you decipher this code and give advice based on the type of code you've received. This article is general knowledge that applies to most furnace brands, but we'll also break down specific furnace error codes based on brand later on.

What Does a Blinking Red Light Mean On a Furnace?

If a red light on your furnace blinks repeatedly you know that something is going wrong. The red blinking light can be an indicator of a number of problems or malfunctions with your heating system, so it is best to act fast if this happens.

Here are some of the most common causes issues to throw an error code:

1. No Signal From Thermostat

Flashing lights could indicate that your thermostat is not sending a signal to the furnace. This problem can be caused by an issue with the wires in your walls, or it might just be that there is a loose wire connection somewhere.

If this happens, you should test out all of your connections and make sure they are tight and not causing any problems. If everything looks like it is in good working order, then it is probably time for a new thermostat.

2. No Power

Don't see a light at all? It might be that there your furnace is not receiving power at all. In that case, you need to go outside and check your circuit breaker box and find the breaker switch the furnace is tied to.

If one of them is out, switch it back on and try again. If the breaker itself is not tripped but there still isn’t any power going to your heating system, you should contact a professional HVAC technician.

3. Flame Failure

This issue means there is not enough gas or air to keep a steady, hot flame going. This problem could be happening because of clogged filters, a dirty burner chamber and tank, broken burners, or too much pressure in your combustion chambers.

Make sure that all the filters are clean and replace them if they look damaged or very dirty. Make sure that there is no debris blocking any parts of the burner chamber or tank. Look and see if there are any broken pieces in the burner chamber itself. A certified heating and cooling contractor can verify this.

4. Igniter Failure

If your furnace is still able to kick on, check and see how many of the fins on your gas burner is not working. If you see any experiencing ignition failure, then it may be that you need to change or repair the igniter. This switch sends a spark near the pilot light to ignite each flame. If you see no flames at all you may have furnace lock requiring emergency heating repair service.

5. Pressure Switch Problem

The furnace's heat exchanger and inducer are two components that ensure the system is venting bad gas. Although this should be addressed by a professional, double-check to see whether your chimney or exhaust is blocked first. That might fix the problem.

Problems with pressure switches can also indicate a condensate drain is plugged or there is another type of vent blockage.

6. Gas Valve Issue

You may have a problem because the gas coming in through your gas line and feeding into your combustion chambers does not have enough pressure to ignite. You could simply adjust the pressure knob so that there is more gas coming through, but it is best to have a system check just to be certain.

7. High Limit Switch & Roll Out Switch

On the inside of your heating system, there are numerous roll out switches that monitor for heat where it isn't supposed to be. The heat sensors are switches that determine when the heat exchanger is too hot. The high limit switch watches the temperature in the heat exchanger. If you have a high limit switch error indication, check to see if your furnace filter needs to be changed. If nothing else works, contact a professional for assistance.

8. Circuit Board Failure

There may be serious damage done to your circuit board or something electrical has come loose inside of your heating system. If this is the case, then you will need to contact a professional heating repair technician because more problems could happen very quickly if not caught in time!

9. Voltage Issue

Flashing lights on your heating system may also mean that there is a voltage issue. If you recently had a new furnace installed, check the voltage at your circuit breakers and make sure that they are set correctly .

Furnace Light Is On But Not Blinking

If your furnace light is on and steady, good news. Your furnace is in working condition and experiencing no errors.

Furnace Error Codes By Brand

There are many different furnace brands, each with its own slightly distinct error messages. However, the manner in which a code is interpreted and the problems that are conveyed are usually very similar. It's best to refer to your owner's manual if you still have it, it not you can find your brand below.

• Trane Furnace Error Codes
• Lennox Furnace Error Codes
• Carrier Furnace Error Codes
• Bryant Furnace Error Codes
• Goodman Furnace Error Codes
• York Furnace Error Codes
• American Standard Furnace Error Codes

Call ARS/Rescue Rooter for Quality Furnace Service

No matter what brand of furnace you own or how many times its light is flashing at you, our skilled heating and air conditioning service technicians can restore comfort to your home. If your furnace is experiencing some issue, find your nearest ARS/Rescue Rooter location or call us at 866-399-2885 to book an appointment with us today!