Operating a Nest thermostat is one of the most convenient ways to optimize the everyday schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make improvements. But as you may expect, it won’t work properly or at all if you see an error code show up. The exact error code provides useful information about the underlying problem, something a professional technician can use to present solutions that much sooner.

Here are seven of the most common error codes you might encounter on your Nest thermostat. We’ll explain the basics of each error code along with how you could fix it and the estimated cost to do so. Keep in mind that while the investment will ultimately depend on the precise Nest model, you can count on paying about $75-$200 for repairs. This should also cover travel and labor costs as well as any specific parts necessary to wrap up repairs.

e298 – Critical

This critical error code is limited to new models of the Nest thermostat and appears when the power is detached 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 could be the circuit breaker, fuse box or system switch. A certified technician can examine electrical connections and wiring until they locate the root of the problem.

e294 – Critical

Critical error code e294 shows up 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 conduct 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 start inspecting connectors.

They’ll detach the power and slowly check each wire, making sure they are fully attached into the connector with the correct amount of exposed copper. After they find the damaged connector, it can be exchanged for a new one.

e195 – Critical

This critical error code can surface when the weather outside is particularly hot. The HVAC system can fail and stop delivering power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will finally power down. In the event the breakers are on, you can examine a few other places before contacting a professional technician.

As this error can consume your thermostat’s battery, the first step could be supplying enough power to figure 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. In the event it reveals 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 struggle to find anything wrong with these components, it will probably be best to contact a pro.

e103 – Critical

Another critical error code, e103 suggests an electrical issue with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is getting more power than necessary. This can stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. The technician can cautiously 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

While this error code isn’t critical, it may still prevent 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 the absence of one can block your Nest from getting sufficient power. You can check 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.

During installation of a Nest Power Connector, you will sometimes notice error code E297 be displayed. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead be required 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 too much power is transported through the Nest’s wiring, it could damage internal components and may even be a fire hazard. If you notice this error code show up on your Nest thermostat and want to protect from electrical damage, it’s a good idea to switch the power off as soon as possible. You can then contact a professional technician with the necessary experience detecting and fixing electrical issues.

e73 – Critical

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

This will sometimes be as simple as the breaker being turned off, but it can 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 looks to be out of place, it’s a good idea to speak with a local professional.