Operating a Nest thermostat is one of the most convenient ways to improve the day-to-day schedule of your comfort system. This smart thermostat can recognize 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 specific error code provides useful information about the root of the problem, something a knowledgeable technician can use to present solutions that much quicker.

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 as well as how you could fix it and the estimated cost to do so. Keep in mind that while the investment will ultimately depend on the specific Nest model, you can anticipate paying about $75-$200 for repairs. This should also cover travel and labor costs on top of any specific hardware 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 disconnected from the system. Since this is a critical power error, the thermostat will swap to the backup battery system. The error message will remain on display until the issue is fixed.

Losing power to your Nest thermostat can be for numerous reasons. The wiring might have disconnected or become damaged, or a disconnection may have occurred further along in your home’s electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician will examine electrical connections and wiring until they find 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 will need to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to make sure it’s not just a software problem. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start checking connectors.

They’ll disconnect the power and gradually check each wire, making sure they are fully attached into the connector with the proper amount of bare copper. After they find the problem connector, it can be swapped for a new one.

e195 – Critical

This critical error code can appear when the weather outside is especially hot. The HVAC system can break down and stop giving power to your Nest thermostat. When this problem persists, the backup battery in your thermostat drains and the thermostat will finally power down. Presuming the breakers are on, you can search a few other places before contacting a professional technician.

As this error can drain your thermostat’s battery, the first step may be restoring enough power to determine if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and supply power through a USB cable. Assuming it displays 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 don’t find anything wrong with these components, it will likely be best to call a pro.

e103 – Critical

Another critical error code, e103 indicates an electrical issue with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is experiencing more power than necessary. This will sometimes stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. A technician will meticulously 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 may still keep you from using the Nest thermostat how you want to. Error code n260 concerns 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 adapt the wiring itself if there is. If not, you need a Nest Power Connector.

During installation of a Nest Power Connector, you may 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 need 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 originating from an overcurrent. If excess power is being delivered inside the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you see this error code appear on your Nest thermostat and want to guard against electrical damage, it’s a good idea to switch the power off straightaway. You can then contact a professional technician with the appropriate experience diagnosing and resolving electrical damage.

e73 – Critical

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

This could be as easy as the breaker being switched off, but it could also be a problem with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually check the wires to make sure nothing is loose or damaged. If nothing seems to be out of place, it’s time to contact a local professional.