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Ecobee Furnace Not Turning Off? 4 Common Causes + Fixes

The range of furnaces Ecobeee offers is exceptionally convenient, offering a powerful system that can heat both small and large homes. But just like any furnace, Ecobee furnaces can have some issues. If you have a brand-new Ecobee furnace or have been using yours for a while and it won’t turn off, it’s time to find the cause and fix it.

Your Ecobee furnace isn’t turning off because your fan limit switch isn’t configured or is faulty, or there are problems with the thermostat. Fix the problem by setting the fan limit switch to auto or replace it if broken, and ensure your thermostat is working by checking the wiring and batteries.

If you can’t seem to get your Ecobee furnace to turn off, then this guide is for you. We’ll educate you on why this might be happening and walk you through the steps to fix each problem.

Incorrect Configuration on the Fan Limit Switch

Let’s start with the configuration of the fan limit switch. The fan limit switch turns the furnace fan off when not needed. The blower fan is responsible for getting air from the furnace to the ductwork that runs through your home. 

The limit switch has three different settings:

  • On
  • Auto
  • Off

If the switch is set to On, it’ll always run. This acts as a “manual override” for the fan’s function — you need to manually turn it off when done using the furnace. If the switch is set to Off, the fan will stop working, so warm air will no longer be blown throughout your home.

How To Fix

If the fan continues to run when the furnace is off, you should inspect the fan limit switch. If the switch is set to On, consider setting it to Auto instead. 

The auto function ensures the fan turns off automatically without input from your side. This is an easy fix that’ll ensure your furnace works as intended. However, make sure you don’t have any other manual overrides configured for the fan. 

The video below will help you troubleshoot the fan limit switch on your furnace:

Faulty Fan Limit Switch

If you find that the switch is already set to Auto, yet the fan continues to run when it shouldn’t, maybe the switch is faulty. 

If your furnace has a faulty fan limit switch, switching it from On to Auto won’t make a difference. The signal required to make this switch won’t be sent to the fan. 

The fan limit switch may have wiring issues. There’s also a good chance that it’s faulty. 

How To Fix

The first step here is to determine whether the switch is the problem. Turn the switch to Off to see what happens. If the fans continue running even though you changed the settings, you know the limit switch doesn’t work. 

The fan limit switch is a relatively small part of the system. But you need to access the interior of your furnace to inspect it. Here’s how:

  1. Shut off your furnace.
  2. Open the main panel.
  3. Locate the switch and check to see if there are any loose wires. If you find loose wires, use the right tools to fasten them to the switch. Also, note where the wires attach on both ends. Ensure the wires are secured at these points too. 
  4. If you can’t see any loose wires, remove the fan limit switch. Inspect it to determine if there are any cracks, marks, or other problems. 

Once you’re done with the troubleshooting and determine that the switch is the problem, get a replacement.

If you’re not sure how this process works, the video below can guide you through the process of replacing the fan limit switch in your furnace:

Problems With Thermostat Wiring

The thermostat is connected to the main circuit control board. In addition to this, the wires run to other parts of the HVAC system too. When you change the furnace settings, it needs to send a signal for this configuration to the appropriate location. 

If you turn the fan off, it needs to signal the blower motor to stop running. When you turn the temperature up, the thermostat sends a signal to the burner, causing the burner’s flame to increase in intensity. 

When there are issues with the thermostat’s wiring, your Ecobee furnace won’t turn off. The thermostat can’t send a signal to the furnace. 

This problem is common when the furnace has run for some time and suffered damage to the wiring. Even though you could turn it off, the furnace won’t respond when turning it off at the thermostat. 

How To Fix

You need to get a reference guide for your furnace and thermostat model for this fix. You can refer to the official Ecobee manual that came with the device. You can also search your model number on the internet to find a guide. 

Use the owner’s manual as a reference. It’ll show you how the thermostat and other HVAC parts are wired. Here’s what you need to do:

  1. Open up your furnace and check the wires that run to the thermostat. 
  2. See if any wires are loose or damaged. Both can cause problems with the thermostat’s ability to switch off the furnace. 
  3. Note how all wires are connected. Use the reference guide to ensure everything is connected to the right parts. 

Thermostat Has Weak Batteries

You turned the furnace on at the start of winter and had it running for some time. When turning it off, you find that the furnace won’t respond to the thermostat. A second look at the thermostat shows that there is no power — the LED lights aren’t on, and there may be nothing displayed on the screen. 

In this scenario, you should see if the thermostat needs new batteries. 

How To Fix

First, you want to determine if your thermostat runs on batteries. You can remove the front panel and check the battery compartment. If there’s a panel fitted with a screw, open it up. This will likely reveal a compartment with batteries. The exact location and type of batteries depend on the thermostat model.

Remove the old batteries and replace them with a new set. Be sure to use the same batteries — check the type and voltage of the old batteries. Once replaced, fit the panel back on to the thermostat and hook the device back into place. 

This video helps you replace the batteries in your thermostat:

Summary

Problems with wiring, a tripped fan limit switch, or dead batteries in the thermostat are possible reasons behind an Ecobee furnace not turning off. Look at all symptoms and carefully examine each part to identify the problem.

If you need to work with wires, call a professional.