How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the best ways to improve the daily schedule of your comfort system. This smart thermostat can learn your preferences and automatically make adjustments. But as you may expect, it won’t work correctly or at all if you see an error code show up. The specific error code offers useful information about the root of the problem, something a professional technician can use to offer solutions that much sooner.

Listed below are seven of the most frequent error codes you could discover on your Nest thermostat. We’ll walk you through the basics of each error code along with how you might fix it and the projected cost to do so. Don't forget that while the costs will ultimately be dependent on the specific Nest model, you can count on paying about $75-$200 for repairs. This should also cover travel and labor costs along with any specific hardware required to finish repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and is displayed when the power is disconnected from the system. Because this is a critical power error, the thermostat will switch to the backup battery system. The error message will remain on the screen until the issue is dealt with.

Losing power to your Nest thermostat can be for several reasons. The wiring may have disconnected or become damaged, or a disconnection could have happened further along in your home's electrical system. This could be the circuit breaker, fuse box or system switch. A professional technician can check electrical connections and wiring until they find the source of the problem.

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to ensure it’s not just a software problem. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start inspecting connectors.

They’ll shut off the power and slowly look at each wire, ensuring they are fully attached into the connector with the correct amount of exposed copper. Once they find the problem connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can surface when the weather outside is especially hot. The HVAC system can fail and stop sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will finally power down. Assuming the breakers are on, you can search a handful of other places before contacting a professional technician.

As this error can deplete your thermostat’s battery, the first step could be providing enough power to determine if this specific error code is what you’re working with. You can disconnect the thermostat from its base and provide power by using a USB cable. In the event it presents error code 195, you can continue to visually check components including the wiring as well as your air conditioner’s air filter or drainage system. If you don’t uncover anything wrong with these components, it will probably be best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 indicates 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 needed. This can stem from the breaker box, an error from the control board or because of a defective connection in the thermostat. Your technician should meticulously inspect and test the Nest’s electrical system to figure out where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

While this error code isn’t critical, it could still keep you from using the Nest thermostat how you prefer to. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as not having one can block your Nest from obtaining adequate power. You can examine the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you need a Nest Power Connector.

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

e104 - Critical

Similar to error code e103, e104 is a critical error that's the result of an overcurrent. If excessive power is sent inside the Nest’s wiring, it may damage internal components and may even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to protect from electrical damage, it’s suggested to switch the power off straightaway. You can then get in touch with a professional technician with the appropriate experience identifying and fixing electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This will sometimes be as straightforward as the breaker being turned off, but it may also be an issue with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure nothing is loose or damaged. If nothing looks to be out of place, it’s time to get in touch with a local professional.