Operating a Nest thermostat is one of the most convenient ways to improve the daily schedule of your HVAC system. This smart thermostat can learn your preferences and automatically make changes. But as you can expect, it won’t work well 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 present solutions that much faster.
Here are seven of the most common error codes you might discover on your Nest thermostat. We’ll explain the basics of each error code along with how you could solve it and the approximate cost to do so. Don't forget that while the price will ultimately depend on the specific 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 components required to wrap up repairs.
e298 - Critical
This critical error code is limited to newer models of the Nest thermostat and shows up when the power is shut off. As this is a critical power error, the thermostat will change 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 could have disconnected or become damaged, or a disconnection could have happened further along in your electrical system. This may be the circuit breaker, fuse box or system switch. A trained technician will inspect 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 needs to be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to ensure it’s not just a software error. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start checking connectors.
They’ll disconnect the power and gradually inspect each wire, ensuring they are fully inserted into the connector with the correct amount of exposed copper. Once they find the problem connector, it can be replaced for a new one.
e195 - Critical
This critical error code can show up when the weather outside is severely hot. The HVAC system can fail and stop delivering power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will eventually turn off. Assuming the breakers are on, you can search a couple of other places before consulting a professional technician.
As this error can consume your thermostat’s battery, the first step may be restoring enough power to find out if this specific error code is what you’re dealing with. You can separate the thermostat from its base and provide power with a USB cable. In the event it displays error code 195, you may continue to visually examine 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 indicates an electrical problem with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is experiencing more power than necessary. This can stem from the breaker box, an error from the control board or through a bad connection in the thermostat. A technician can cautiously inspect and test the Nest’s electrical system to understand where the power is surging or why the thermostat is convinced there’s an overcurrent problem.
While this error code isn’t critical, it could 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 inspect the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you can get a Nest Power Connector.
Due to installation of a Nest Power Connector, you may notice error code E297 appear. This can be remedied 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
Similar to error code e103, e104 is a critical error originating from an overcurrent. If too much power is being delivered using the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to take steps to prevent electrical damage, it’s suggested to switch the power off as soon as you can. You can then get a hold of a professional technician with the proper experience detecting and resolving electrical issues.
e73 - Critical
When your thermostat displays error code e73, it means that the Rc wire is not getting power. This might be as straightforward as the breaker being switched off, but it can also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure none of them are loose or damaged. If nothing looks to be out of place, it’s best to speak with a local professional.