Installing a Nest thermostat is one of the easiest ways to improve the day-to-day schedule of your HVAC system. This smart thermostat can learn your preferences and automatically make improvements. But as you might expect, it won’t work correctly or at all if you see an error code show up. The precise error code offers useful information about the root of the problem, something a professional technician can use to provide solutions that much sooner.
Here are seven of the most likely error codes you could find on your Nest thermostat. We’ll explain the basics of each error code as well as how you might fix it and the approximate cost to do so. Keep in mind that while the costs will ultimately be dependent on the specific Nest model, you can count on paying around $75-$200 for repairs. This should include things like travel and labor costs on top of any specific hardware necessary to wrap up repairs.
e298 - Critical
This critical error code is limited to new models of the Nest thermostat and is displayed when the power is detached from the system. Because 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 fixed.
Losing power to your Nest thermostat can be for several reasons. The wiring may have disconnected or become damaged, or a disconnection may have appeared further along in the electrical system. This might be the circuit breaker, fuse box or system switch. A trained 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, the technician will need to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to ensure it’s not just a software problem. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and begin checking connectors.
They’ll shut off the power and gradually check each wire, making sure they are fully placed into the connector with the correct amount of exposed copper. After they pinpoint the malfunctioning connector, it can be swapped for a new one.
e195 - Critical
This critical error code can appear when the weather outside is particularly hot. The HVAC system can shut down and stop sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will eventually power down. Presuming the breakers are on, you can examine a handful 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 dealing with. You can detach the thermostat from its base and supply power with a USB cable. Assuming it reveals error code 195, you can 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 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 issue with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is receiving more power than needed. This can stem from the breaker box, an error from the control board or through a faulty connection in the thermostat. Your technician can meticulously inspect and test the Nest’s electrical system to figure out where the power is surging or why the thermostat is convinced there’s an overcurrent problem.
Even though this error code isn’t critical, it can still prevent 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 the absence of one can block your Nest from obtaining sufficient 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.
During installation of a Nest Power Connector, you might notice error code E297 be displayed. This can be remedied 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
Just like 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 may damage internal components and could even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to guard against electrical damage, it’s recommended to shut the power off straightaway. You can then contact a professional technician with the proper experience identifying and fixing electrical issues.
e73 - Critical
When your thermostat displays error code e73, it means that the Rc wire is not getting power. This could be as straightforward as the breaker being shut off, but it could also be something with the wiring. After turning off the power to your HVAC system and thermostat, you can visually check the wires to make sure none of them are loose or damaged. If nothing seems to be out of place, it’s best to get in touch with a local professional.