Using a Nest thermostat is one of the best ways to perfect the day-to-day schedule of your heating and cooling. 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 supplies useful information about the source of the problem, something a trained technician can use to present solutions that much faster.

Here are seven of the most frequent error codes you may find on your Nest thermostat. We’ll explain the basics of each error code along with how you might address it and the estimated cost to do so. Keep in mind that while the costs will ultimately depend on the exact Nest model, you can count on paying about $75-$200 for repairs. This should include things like travel and labor costs as well as any specific parts needed to complete repairs.

e298 – Critical

This critical error code is limited to newer models of the Nest thermostat and shows up when the power is disconnected from the system. As 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 resolved.

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

They’ll detach the power and gradually look at each wire, making sure they are fully inserted into the connector with the correct amount of bare copper. After they pinpoint the problem connector, it can be swapped 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 giving power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will finally shut down. Presuming the breakers are on, you can check a handful of other places before contacting a professional technician.

As this error can drain your thermostat’s battery, the first step might be restoring enough power to figure out if this specific error code is what you’re dealing with. You can detach the thermostat from its base and deliver power through a USB cable. Assuming it reveals error code 195, you should continue to visually examine components like the wiring as well as your air conditioner’s air filter or drainage system. If you can’t find anything wrong with these components, it will probably be best to call a pro.

e103 – Critical

Another critical error code, e103 signifies an electrical malfunction with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is getting more power than what is safe and normal. This will sometimes stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. The technician can carefully inspect 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

Although this error code isn’t critical, it might 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 getting 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 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

Just like error code e103, e104 is a critical error originating from an overcurrent. If excess power is sent inside 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 guard against electrical damage, it’s recommended to shut the power off straightaway. You can then get in touch with a professional technician with the appropriate experience identifying and solving electrical damage.

e73 – Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power.

This might be as simple as the breaker being switched off, but it could also be an issue with the wiring. After switching off the power to your HVAC system and thermostat, you can visually examine the wires to make sure none of them are loose or damaged. If nothing appears to be out of place, it’s time to contact a local professional.