Installing a Nest thermostat is one of the easiest ways to optimize the daily schedule of your comfort system. This smart thermostat can learn your preferences and automatically make adjustments. But as you might expect, it won’t work correctly or at all if you see an error code on the display. The specific error code offers useful information about the underlying problem, something a knowledgeable technician can use to provide solutions that much quicker.
Here are seven of the most common error codes you could discover on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you can fix it and the estimated cost to do so. Keep in mind that while the price will ultimately be dependent on the exact Nest model, you can expect to pay around $75-$200 for repairs. This should include things like travel and labor costs on top of any specific parts required to finish repairs.
e298 - Critical
This critical error code is limited to new models of the Nest thermostat and shows up when the power is disconnected from the system. Because 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 issue is fixed.
Losing power to your Nest thermostat can be for numerous reasons. The wiring may have disconnected or become damaged, or a disconnection may have appeared further along in the electrical system. This may be the circuit breaker, fuse box or system switch. A professional technician will check electrical connections and wiring until they uncover the source of the problem.
e294 - Critical
Critical error code e294 is displayed when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to ensure it’s not merely a software problem. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start checking connectors.
They’ll detach the power and gradually check each wire, making sure they are fully attached into the connector with the proper amount of exposed copper. Once they find 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 break down and stop delivering power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will finally power down. Assuming the breakers are on, you can search a couple of other places before calling a professional technician.
Since this error can consume your thermostat’s battery, the first step could be providing enough power to figure out if this specific error code is what you’re facing. You can detach the thermostat from its base and supply power through a USB cable. Assuming it displays error code 195, you should continue to visually check components such as the wiring as well as your air conditioner’s air filter or drainage system. If you can't detect 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 problem with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is receiving more power than needed. This will sometimes stem from the breaker box, an error from the control board or thanks to a bad connection in the thermostat. A technician can cautiously examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat thinks there’s an overcurrent problem.
While this error code isn’t critical, it might still stop you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as missing 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 adjust the wiring itself if there is. If not, you need a Nest Power Connector.
Due to installation of a Nest Power Connector, you might notice error code E297 appear. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead be required 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 excess power is sent inside the Nest’s wiring, it may damage internal components and could even be a fire hazard. If you notice this error code appear 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 a hold of a professional technician with the necessary experience diagnosing and solving electrical damage.
e73 - Critical
When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This might be as simple as the breaker being shut off, but it may also be something with the wiring. After turning off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure they’re not loose or damaged. If nothing looks to be out of place, it’s a good idea to speak with a local professional.