Carrier Furnace Flashing Red/Yellow/Orange Light!

By - Rajib Ahmed

Updated -

Ever wondered what the blinking yellow/orange/red lights mean on your Carrier furnace? You probably understand the machine is trying to communicate something, but what? 

Well, you’ve come to the right place for answers. Furnace error codes vary depending on the brand. 

Therefore, what a specific color code and its blinking patterns signify for one brand may differ for another. 

This article explains comprehensively what the red/yellow/orange error lights mean in a Carrier furnace. 

A flashing red light in a Carrier furnace usually means a fault with the pressure switch. A blinking yellow light signifies the Carrier furnace is in high-fire mode (usually a problem with the blower fan). Lastly, the orange light indicates dirt buildup in the burn–this happens when there’s an insufficient mixture of gas and oxygen within the furnace. 

In this article, I will delve deeper into the meaning of each error light and its fixes. 

I will also explain in detail how to read error codes on a Carrier furnace with various examples and their meanings. 

You will understand the function of a Carrier furnace’s red, yellow, and orange error lights. 

What Does a Flashing Red Light Mean on a Carrier Furnace?

Carrier Furnace Flashing Red/Yellow/Orange Light with Errors

A flashing red light on a Carrier furnace can stem from either of the following problems:

  • A faulty gas valve
  • Circuit board failure 
  • Pressure switch issues
  • Faulty thermostat

It is important to note that a solid red light on your Carrier furnace indicates that the unit has shut itself off due to a detected problem. 

Notify a qualified HVAC technician immediately to run diagnostics, make repairs, or replace parts where necessary. 

Below is a broader explanation of each of the highlighted causes of a blinking error light in a Carrier furnace:

#1. A Faulty Gas Valve

A faulty gas valve can restrict the furnace’s ability to ignite. It is usually the case when the gas flowing through the gas lines and into the combustion chamber lacks sufficient pressure. 

This fault can cause the Carrier furnace’s red error light to blink. Confirm if the furnace’s gas supply is open to fixing a faulty gas valve. 

If it isn’t, open it and see if there is any improvement in gas flow. If the issue persists, the problem might be closely related to the ignitor. 

If the ignitor is faulty, then combustion will be impossible within the furnace. 

To confirm if the problem is from the ignitor, follow the troubleshooting steps below:

  • Switch off the furnace
  • Detach the two wires on the gas valve from their terminals. 
  • Test for current in the wires by attaching multimeter probes.
  • Switch the furnace back on.
  • Carefully inspect the readings from the multimeter once the furnace turns on. If the readings do not fall between 24-120 volts, the ignitor has a problem. 

The control board is most likely faulty. 

I recommend notifying an HVAC technician immediately to run diagnostics and confirm if the gas valve, ignitor, or control board would need repairs or replacement. 

#2. Circuit Board Failure

There is a high chance something might be wrong with the circuit board of your Carrier furnace if the red error light starts blinking. 

The issue might be due to loose wiring within the furnace or damage to the transistors due to power surges. 

If there is a problem with the circuit board failure, it is best to replace the board entirely rather than opt for repairs. Ensure you use a certified HVAC technician for the replacement. 

#3. Pressure Switch Issues

Pressure switch issues mainly affect the furnace’s heat exchanger and inducer. 

These two components in the Carrier furnace are responsible for venting out bad gas from the heating system. 

If the pressure switch becomes faulty, exhaust fumes will fill the furnace and cause further damage to the system. 

Below are a few things that can cause a faulty pressure switch:

  • Leaks around the assemblies
  • Electrical damage to the pressure switch
  • Damage was done to the draft inducer motor.
  • Blocked condensate drainage

Most times, simply cleaning out the clogged drainage might solve the issue. Have a qualified HVAC technician take a look and either repair the issue or replace the pressure switch entirely. 

#4. Faulty Thermostat

When your thermostat is not sending signals to the furnace, it is a problem and can lead to the red error light blinking. 

The problem is primarily due to loose wire connections within the system. Inspect the wiring connections to fix a faulty thermostat to see if they are all tightly fixed.

Tighten loose wire connections, if any. If the issue persists, replace the thermostat completely. Remember to only use a qualified HVAC technician for the job.

What Does the Yellow Light Indicate on a Carrier Furnace?

The yellow light on a Carrier furnace indicates the furnace is frozen in high-fire mode. The system’s “High-fire mode” in a functioning Carrier furnace should only work for brief intervals. 

This way, it can heat a house faster and more adequately. The yellow light may also result from a defective gas valve solenoid. 

It is important to note that there is nothing to worry about if the Carrier furnace displays a solid yellow light. 

The solid yellow light indicates that the furnace is working and fully powered. A problem occurs when there is blinking. 

Fix For Yellow Light Display On A Carrier Furnace

Usually, the source of the problem for a yellow light on a Carrier furnace is the gas valve solenoid. 

The gas valve solenoid opens whenever the thermostat signals for more heat. 

The gas valve shrinks its opening at intervals for “Low-fire mode” and widens it again when the thermostat switches to “High-fire mode.” 

You can consult a certified HVAC technician for repairs or run diagnostics. However, in most cases, it is best to replace the gas valve solenoid entirely. 

How Do You Read the Error Codes on a Carrier Furnace?

The first number of each error code signifies the number of short flashes, while the second number represents the number of long flashes. 

It is one thing to spot an error code and another to be able to read and understand what it means. 

However, the first step to understanding an error code’s meaning is studying the blinking patterns. 

You can tell a lot about the meaning of a particular error light code by the number of times it blinks and the flash pattern. 

Below is a table that details different blinking patterns and their meanings:

Blinking PatternError Code Meaning
Continuous solid light (no blinking)No error; the system has a total power supply. 
Rapid blinkingLine polarity reversed
1-2 blinksBlower on after power-up.
1-3 blinksLimit or flame roll-out switch lockout
1-4 blinksIgnition lockout

Why Is There a Flashing Orange Light on My Carrier Furnace?

A flashing orange light on your Carrier furnace could indicate dirt buildup in the burners, most likely hindering gas supply to the burners. 

Therefore, the orange light signifies an improper mixture between the gas in the furnace and the oxygen supply. The blinking orange light can also mean an issue with the furnace’s thermostat. 

It usually means the thermostat is due for replacement. 

Fix For Flashing Orange Light 

Replace the furnace’s thermostat completely. It would be best if you replaced thermostats every five years. 

Ensure you program the thermostats before using them and only do while the furnace is off to avoid shorting the fuse. 

To avoid the hassle of repairing and replacing yourself, notify a qualified HVAC technician to do it for you instead. Here is a link to a few good-quality thermostats you can purchase.

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Last update on 2024-01-06 / Affiliate links / Images from Amazon Product Advertising API


#1. What Color Should My Carrier Furnace Light Be?

Your furnace should display a solid yellow or amber light to indicate that it is running smoothly and is fully powered. 

#2. How Do You Read a Furnace Error Code?

To read a furnace error code, look for the error lights and take note of their blinking patterns. However, furnace codes and their meanings vary between different brands. 

#3. What Are Signs That My Furnace Needs Repairs?

A few signs include discolored pilot light, hard starting, and persistent noises. 

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