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 day-to-day schedule of your heating and cooling. This smart thermostat can learn your preferences and automatically make changes. But as you can expect, it won’t work properly or at all if you see an error code show up. The precise error code provides useful information about the root of the problem, something a knowledgeable technician can use to present solutions that much quicker.

Let's consider seven of the most likely error codes you might encounter on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you might address it and the approximate cost to do so. Keep in mind that while the costs will ultimately depend on the precise Nest model, you can count on paying about $75-$200 for repairs. This should include travel and labor costs along with any specific hardware required to wrap up repairs.

e298 - Critical

This critical error code is limited to newer 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 issue is dealt with.

Losing power to your Nest thermostat can be for numerous reasons. The wiring might have disconnected or become damaged, or a disconnection could have occurred further along in the electrical system. This might be the circuit breaker, fuse box or system switch. A trained technician should 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 should reconfigure the R wire. They’ll first perform a factory reset of your thermostat to ensure it’s not just a software issue. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin inspecting connectors.

They’ll detach the power and slowly inspect each wire, ensuring they are fully placed into the connector with the proper amount of uncovered copper. After they pinpoint the problem connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can appear when the weather outside is severely hot. The HVAC system can shut 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. Presuming the breakers are on, you can check a couple of other places before calling a professional technician.

Because this error can drain your thermostat’s battery, the first step might be restoring enough power to find out if this specific error code is what you’re working with. You can detach the thermostat from its base and provide power through a USB cable. If it reveals error code 195, you should continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you don’t detect anything wrong with these components, it's maybe best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical error with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is experiencing more power than what is safe and normal. This may stem from the breaker box, an error from the control board or thanks to a bad connection in the thermostat. A technician will cautiously inspect and test the Nest’s electrical system to determine 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 prefer to. Error code n260 refers to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from getting sufficient power. You can inspect the Nest’s C connector for the presence of a C wire and adjust 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 appear. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been 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 too much power is being delivered using the Nest’s wiring, it can damage internal components and may 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 a good idea to turn the power off as soon as you can. You can then contact a professional technician with the proper experience detecting and resolving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This may be as easy as the breaker being shut off, but it may also be a problem with the wiring. After switching 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 seems to be out of place, it’s best to speak with a local professional.