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 optimize the daily schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make adjustments. But as you might expect, it won’t work well or at all if you see an error code on the display. The specific error code provides useful information about the underlying problem, something a knowledgeable technician can use to provide solutions that much sooner.

Here are seven of the most common error codes you could find on your Nest thermostat. We’ll explain the basics of each error code on top of how you can fix it and the projected cost to do so. Keep in mind that while the price will ultimately be dependent on the precise Nest model, you can expect to pay between $75-$200 for repairs. This should also cover travel and labor costs on top of any specific parts needed to wrap up repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and appears when the power is detached from the system. Since this is a critical power error, the thermostat will change to the backup battery system. The error message will continue to be displayed until the problem is resolved.

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

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring needs to be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to make sure it’s not merely a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start looking at connectors.

They’ll detach the power and slowly check each wire, seeing to it that they are fully attached into the connector with the correct amount of bare copper. After they find the damaged connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can surface when the weather outside is particularly 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 finally turn off. In the event the breakers are on, you can search a few other places before calling a professional technician.

Because this error can deplete your thermostat’s battery, the first step could be restoring enough power to figure out if this specific error code is what you’re facing. You can detach the thermostat from its base and provide power by using a USB cable. In the event it displays error code 195, you can continue to visually inspect components such as the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to uncover anything wrong with these components, it's maybe best to call a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical malfunction with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is getting more power than necessary. This will sometimes stem from the breaker box, an error from the control board or through a faulty connection in the thermostat. A technician will meticulously examine 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

Even though 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 obtaining enough power. You can inspect the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you can get a Nest Power Connector.

During installation of a Nest Power Connector, you will sometimes notice error code E297 be displayed. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead be required 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 stemming from an overcurrent. If excess power is being delivered inside the Nest’s wiring, it can damage internal components and can even be a fire hazard. If you see this error code pop up on your Nest thermostat and want to take steps to prevent electrical damage, it’s suggested to shut the power off straightaway. You can then get in touch with a professional technician with the necessary experience identifying and solving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power. This will sometimes be as simple as the breaker being turned off, but it could also be an issue with the wiring. After turning off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure none of them are loose or damaged. If nothing appears to be out of place, it’s best to speak with a local professional.