How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the most convenient ways to improve the everyday schedule of your comfort system. This smart thermostat can be taught your preferences and automatically make changes. But as you may expect, it won’t work properly or at all if you see an error code appear. The specific error code supplies useful information about the underlying problem, something a trained technician can use to provide solutions that much faster.

Let's consider seven of the most common error codes you may discover on your Nest thermostat. We’ll explain the basics of each error code along with how you might address it and the estimated cost to do so. Keep in mind that while the costs will ultimately depend on the exact Nest model, you can count on paying around $75-$200 for repairs. This should include things like travel and labor costs as well as any specific components needed to finish repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and shows up when the power is detached from the system. As this is a critical power error, the thermostat will change to the backup battery system. The error message will remain on the screen until the problem is resolved.

Losing power to your Nest thermostat can be for numerous reasons. The wiring could have disconnected or become damaged, or a disconnection could have occurred further along in your electrical system. This could be the circuit breaker, fuse box or system switch. A knowledgeable technician should inspect electrical connections and wiring until they locate the root of the problem.

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring has to be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first perform a factory reset of your thermostat to ensure it’s not simply a software problem. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin looking at connectors.

They’ll disconnect the power and progressively look at each wire, making sure they are fully placed into the connector with the correct amount of bare copper. Once they locate the malfunctioning connector, it can be swapped for a new one.

e195 - Critical

This critical error code can surface when the weather outside is severely hot. The HVAC system can fail and stop sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will eventually power down. Assuming the breakers are on, you can inspect a couple of other places before calling a professional technician.

Since this error can drain your thermostat’s battery, the first step might be restoring enough power to determine if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and provide power by using a USB cable. In the event it reveals error code 195, you should continue to visually check components like the wiring as well as your air conditioner’s air filter or drainage system. If you don’t find anything wrong with these components, it will likely be best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical issue with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is getting more power than needed. This can stem from the breaker box, an error from the control board or because of a bad connection in the thermostat. A technician should cautiously investigate and test the Nest’s electrical system to understand where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Although this error code isn’t critical, it might still stop you from using the Nest thermostat how you want to. Error code n260 refers to the lack of a C wire or Nest Power Connector, as not having one can block your Nest from receiving sufficient power. You can examine the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you’ll need a Nest Power Connector.

During installation of a Nest Power Connector, you may notice error code E297 show up. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been installed, you’ll instead have to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.

e104 - Critical

Like error code e103, e104 is a critical error originating from an overcurrent. If excessive power is sent inside the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to take steps to prevent electrical damage, it’s recommended to switch the power off straightaway. You can then get in touch with a professional technician with the necessary experience diagnosing and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This might be as straightforward as the breaker being switched off, but it may also be an issue with the wiring. After switching off the power to your HVAC system and thermostat, you can visually examine the wires to make sure none of them are loose or damaged. If nothing seems to be out of place, it’s time to contact a local professional.