How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the best ways to optimize 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 appear. The precise error code provides useful information about the underlying problem, something a trained technician can use to offer solutions that much faster.

Here are seven of the most likely error codes you may find on your Nest thermostat. We’ll explain the basics of each error code as well as how you could fix it and the approximate cost to do so. Don't forget that while the price will ultimately depend on the precise Nest model, you can expect to pay around $75-$200 for repairs. This should include travel and labor costs along with any specific parts required to complete 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 swap to the backup battery system. The error message will continue to be displayed until the issue is resolved.

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

e294 - Critical

Critical error code e294 is displayed when your Nest thermostat’s wiring has to be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to ensure it’s not simply a software error. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start looking at connectors.

They’ll detach the power and gradually inspect each wire, ensuring they are fully placed into the connector with the correct amount of exposed copper. Once they pinpoint the malfunctioning connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can appear 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 subsequently power down. Assuming the breakers are on, you can check a handful of other places before contacting a professional technician.

Since this error can consume your thermostat’s battery, the first step could be supplying enough power to find out if this specific error code is what you’re dealing with. You can detach the thermostat from its base and provide power with a USB cable. If it reveals error code 195, you may continue to visually check components such as the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to find anything wrong with these components, it will likely be best to contact a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical error with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is receiving 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. The technician will carefully examine 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

Although this error code isn’t critical, it might still prevent you from using the Nest thermostat how you want 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 getting adequate 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.

Due to installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead need 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 that's the result of an overcurrent. If excess power is being delivered through the Nest’s wiring, it could 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 recommended to turn the power off as soon as possible. You can then get in touch with a professional technician with the appropriate experience identifying and solving electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This might be as straightforward as the breaker being shut off, but it may also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually examine 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 contact a local professional.