How To Fix Nest Thermostat Fan Not Working Issue?

Whenever your Nest thermostat fan not working there are a few reasons why this would happen.

Nest thermostat fan functionality is dependent on several factors that we’ll be discussing in this post.

We’ve prepared a detailed solution guide at your disposal to help you not only solve the problem but also discover the origin of the problem.

When your Nest thermostat fan is not working you should start by making sure that the device is powered on and that the fan is enabled from the settings. The next step would be to inspect the batteries and eventually perform a factory reset to solve the issue.

With that in mind, let’s proceed with the proven to work solution guide and help you discover and prevent the reason for the problem in the future.

How To Fix When Nest Thermostat Fan Only Not Working?

We strongly recommend not skipping any of the solutions since the guide is designed to address each possibility via the method of exclusion.

We’ll address each possibility until you’re left with the true cause which we’ll definitely solve.

Here is how to solve the non-spinning fan issue on your Nest thermostat:

Solution #1 Turn On Nest Thermostat

In order for the fan of your Nest thermostat to start running, your thermostat must be turned on.

When the thermostat is disabled or is off its schedule, you will notice that neither the fan will spin nor the temperatures will change.

In that regard, you will need to start your thermostat and check if the thermostat’s fan will run automatically.

Moreover, ensure that your HVAC system is also functional since any failure on its side will prevent not only the fan from spinning but the heating and cooling as well.

Note: There is no catch to turning on your Nest thermostat. One-touch on the display should get it started.

Solution #2 Enable Fan From Settings

If the Nest thermostat fan not working after starting up your thermostat, it may be disabled from the settings.

Directly through your thermostat, you will be able to choose for how long you want the fan to spin.

You can choose from time intervals of 15 minutes up to 3 hours for the fan in your Nest to spin non-stop.

Here’s how to enable the fan from the settings:

1. Tap the screen of your Nest.
2. Open the settings configuration.
3. Head over to fan settings.
4. Wait for the time interval slider to appear.
5. Scroll across the available time settings of your Nest fan.
6. Choose a suitable time interval and tap on “Confirm”.
7. Wait for the fan to start up.

Note: The fan will automatically shut down after the time you’ve appointed in the fan settings configuration.

Solution #3 Enable HVAC System Power

Nest thermostats use two alkaline batteries but receive their power from the HVAC system.

If the HVAC system doesn’t currently have an active power flow, the Nest thermostat may not work in the first place, hence, the fan will not be spinning.

In that regard, in this solution, you need to enable the power flow to the HVAC system and check if the fan would run then.

Generally, most HVAC system furnaces have a power button that when clicked, will automatically let the power in your system and therefore start supplying the thermostat.

You will want to hold the power button on your HVAC furnace for at least 5 seconds so it can light up.

Once the button lights up, it means that power is flowing through the system and your thermostat.

Note: If your furnace doesn’t have a power button, check the situation with the circuit breaker and flip it if necessary.

Solution #4 Replace Nest Batteries

The HVAC system is not the only power source for your Nest thermostat.

This fan problem can also occur due to worn-out batteries and you will have to replace them to get the fan going again.

Here’s how to replace your Nest’s batteries:

1. Undo the 2 bolts keeping the thermostat on the wall.
2. Remove the back panel to expose the batteries.
3. Grab a fresh set of two AA alkaline batteries.
4. Remove the old ones.
5. Insert the new batteries inside the thermostat.
6. Re-attach the compartment.

Note: Be aware of how you put the batteries inside of the thermostat so they make contact with the electric poles.

Solution #5 Reset The Nest Thermostat

A solution for all software troubles with the Nest thermostat is the factory reset.

This will surely solve the problem with the fan if in this case, a software bug is preventing the fan from spinning upon enabling it.

Here’s how to factory reset your Nest thermostat in easy-to-follow instructions:

1. Tap the display of your Nest.
2. Choose the Settings icon.
3. Turn the ring once and choose Reset.
4. Turn the ring again and choose All Settings.
5. Confirm that you want to proceed with the reset.
6. Wait for the thermostat to finish erasing all settings.

Note: The settings and schedules loss of the reset is irreversible for the thermostat.

What To Do When Nest Thermostat Fan Wire Not Working?

So, the solutions above didn’t help fix the fan of your thermostat and you’re coming up with the conclusion that the wire is faulty?

No problem! In such a case, you can either reconnect the wire and check if that would fix the issue or replace the entire wire.

Note: Before we begin, open the Nest app, go to Settings and choose the feature Wiring Diagram, which also includes the fan wire. 

The wiring diagram will show how all of the wires within your Nest thermostat should be connected and you can follow the order there.

Here’s how to connect your Nest thermostat’s fan wire to fix the issue:

1. Take the front panel of the thermostat off.
2. Expose all wires in your thermostat (Y1, Y2, G, W1, W2, C, and R wires).
3. Follow the diagram on your Nest app.
4. Connect each of the wires as it is displayed in the Wiring diagram.

The Nest app will show the complete setup of the wires so you won’t have to ponder which wire goes where.

If the fan didn’t work even after connecting all wires correctly, contact an HVAC professional to replace the fan wire and get the problem fixed!

Thus, to solve the problem where your Nest thermostat fan is not spinning, begin with restarting your thermostat and your HVAC system. Next, enable the fan from the thermostat settings and replace the AA alkaline batteries. Conclude with a factory reset to solve the problem.

Read Next: Best Settings For Nest Thermostat – Complete Guide!

Bottom Line:

Whenever your Nest thermostat fan not working you can always come back to this post to attempt our solutions and hopefully solve the problem.

Keep in mind that the fan is a hardware piece with a pre-determined RPM count, which is really old, and might eventually come to an end-life.

In such cases, the best approach would be to check if your warranty is intact and contact Nest customer service for a replacement or repair.

If this post was helpful, save it for future use and check for more solutions that you might need in our online blog.