Carrier Furnace not Turning On.

Carrier Furnace not Turning On [Solved].

A malfunctioning Carrier furnace that refuses to turn on can be a frustrating and discomforting issue, particularly during the colder months.

When this critical heating system fails to start, it can result from various underlying causes, such as electrical problems, thermostat issues, or mechanical failures.

Troubleshooting and addressing the root cause of this problem is essential to restore warmth and comfort to your home.

At a glance: Carrier Furnace not Turning On due to Problems With the Thermostat,Tripped Breaker Switch,The Fan Is Off or Unlit Pilot Light.

In this guide, we will explore common reasons behind a Carrier furnace not turning on and provide insights into potential solutions to help you diagnose and rectify the issue, ensuring your heating system operates smoothly.

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Why your Carrier Furnace won’t turn on.

We have compiled a list of common reasons why your Carrier furnace won’t turn on. We’ll help you fix the problem so that you and your family can stay warm. 

1.Problems With the Thermostat.

Problems with the thermostat are a common culprit when a Carrier furnace refuses to turn on. The thermostat acts as the command center for your heating system, and issues with it can disrupt the furnace’s operation. Here’s a closer look at potential thermostat-related problems and how to address them:

  1. Dead Batteries: If your thermostat uses batteries and they’re depleted, it won’t be able to send signals to the furnace. In such cases, the furnace won’t start because it’s waiting for instructions from the thermostat.

How to Fix: Remove the thermostat from the wall, locate the battery compartment on the back, replace the batteries with a fresh pair, reattach the thermostat, and test it.

  1. Power Cable Issues: Some thermostats are directly powered and don’t rely on batteries. If the cables providing power to the thermostat are damaged or improperly connected, the thermostat won’t function.

How to Fix: Turn off the furnace and remove the thermostat from the wall. Inspect the wires connected to the furnace. If you find a loose or disconnected wire, reattach it securely. If the C-wire is damaged, it’s best to seek assistance from a professional for replacement.

2.Tripped Breaker Switch.

Another common issue that can prevent a Carrier furnace from turning on is a tripped breaker switch. The breaker switch is a crucial safety component found inside the furnace’s power box, designed to safeguard the system from power surges that could potentially damage it.

Here’s a detailed explanation of this problem and how to address it:

The breaker switch acts as a protective measure against power surges, which can be harmful to electrical appliances, including your furnace.

How to Fix:

  • Locate the Power Box: Look for the power box, which is sometimes referred to as the fuse box. It contains both the breaker switch and a fuse, serving as two distinct safety features for the furnace.
  • Power Off: Ensure that all power to the furnace is turned off.
  • Access the Box: Remove the screws that secure the front panel of the power box in place.
  • Inspect the Breaker Switch: Examine the breaker switch. If you’re unsure about its location, consult your owner’s manual. If the switch has tripped, reset it by flipping it back to its original position.
  • Check the Fuse: While you’re inspecting the breaker switch, also examine the fuse. Verify that the wire inside the fuse is intact. If it’s damaged or blown, replace it with a fuse of the same rating.

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3.The Fan Is Off.

A frequently overlooked yet common issue related to a Carrier furnace not turning on involves the furnace fan. The fan switch typically offers three settings: ON, OFF, and AUTO.

Most people prefer the AUTO setting, allowing the fan to operate based on the furnace’s running status. However, when the fan is set to OFF, it may appear that the furnace isn’t functioning because you’re not receiving any heat in your home.

How to Fix:

  • Locate the Fan Switch: Refer to your owner’s manual to find the fan switch’s location in your Carrier furnace.
  • Check the Fan Setting: If you find the fan switch in the OFF position, switch it to AUTO or ON. This adjustment allows the fan to work in coordination with the furnace’s heating cycle.
  • Inspect Wiring: If the fan switch is already in the correct position (AUTO or ON), but the fan isn’t functioning, inspect the cables that connect the switch to the rest of the system. Look for loose or damaged wires that may be causing the issue.

4.Unlit Pilot Light.

An unlit pilot light can be a potential reason for your Carrier furnace not turning on, particularly in older furnace models that rely on a pilot light rather than an electric ignitor. To determine whether your furnace has a pilot light, inspect the furnace itself. But why is the pilot light’s status important in this context?

The pilot light’s role is critical—it ignites the gas coming from the burners and maintains a small, steady flame.

How to Fix:

  1. Check for a Flame: To address this issue, you’ll need a candle lighter. Before attempting to turn on the furnace, ensure that there is a flame on the pilot light. If you don’t see a flame, proceed to the next step.
  2. Clean the Pilot Light: Over time, soot can accumulate on the pilot light, preventing it from lighting up. To rectify this, open the furnace and gently use fine sandpaper to clean the pilot light.
  3. Ignite the Pilot Light: After cleaning, use the candle lighter to reignite the pilot light. Once it’s lit, attempt to turn on the furnace.

If cleaning the pilot light and reigniting it doesn’t solve the issue, it’s advisable to seek assistance from an HVAC technician. They can diagnose and resolve any more complex problems with the pilot light, ensuring your Carrier furnace operates reliably.

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Frequently Asked Questions (FAQs)

Why isn’t my Carrier furnace turning on?

There could be several reasons, but some common ones include thermostat issues, a tripped breaker switch, a fan set to the “OFF” position, or an unlit pilot light in older furnace models.

How can I troubleshoot a thermostat problem with my Carrier furnace?

First, make sure the thermostat is powered and set to a temperature higher than the current room temperature. If it uses batteries, replace them. If it’s powered by a cable, check for loose wires and ensure the C-wire is intact.

What should I do if my Carrier furnace trips the breaker switch?

Locate the power box (sometimes called the fuse box), turn off all power to the furnace, and inspect the breaker switch. If it’s tripped, reset it by flipping it back. Additionally, check the fuse inside the box to ensure the wire is intact. If it’s damaged, replace it with a fuse of the same rating.

My older Carrier furnace with a pilot light won’t start. What can I do?

If your older furnace uses a pilot light, ensure it’s lit. Use a candle lighter to ignite the pilot light. If there’s no flame, clean the pilot light with fine sandpaper and then attempt to light it again. If this doesn’t work, consider seeking assistance from an HVAC technician for further diagnosis and repair.

Also read>>>Carrier Furnace Light Blinking 3 Times.


A Carrier furnace not turning on can be attributed to various issues, including thermostat problems, tripped breaker switches, fan settings, and unlit pilot lights in older models. With these troubleshooting steps, you can often identify and address these common culprits, ensuring your furnace functions efficiently and keeps your home warm.