Using a Nest thermostat is one of the best ways to improve the everyday schedule of your comfort system. This smart thermostat can be taught your preferences and automatically make improvements. But as you can expect, it won’t work properly or at all if you see an error code on the display. The precise error code offers useful information about the root of the problem, something a professional technician can use to present solutions that much quicker.
Here are seven of the most common error codes you could find on your Nest thermostat. We’ll review the basics of each error code as well as how you might solve it and the estimated cost to do so. Don't forget that while the costs will ultimately depend on the exact Nest model, you can count on paying about $75-$200 for repairs. This should also cover travel and labor costs along with any specific components needed to wrap up repairs.
e298 - Critical
This critical error code is limited to the latest models of the Nest thermostat and shows up when the power is detached 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 dealt with.
Losing power to your Nest thermostat can be for several 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 trained technician will examine electrical connections and wiring until they uncover the source of the problem.
e294 - Critical
Critical error code e294 is displayed when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not merely a software problem. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin looking at connectors.
They’ll shut off the power and slowly inspect each wire, making sure they are fully inserted into the connector with the proper amount of bare copper. After they find the problem connector, it can be replaced for a new one.
e195 - Critical
This critical error code can surface when the weather outside is especially hot. The HVAC system can shut down and stop giving power to your Nest thermostat. When this problem persists, the backup battery in your thermostat drains and the thermostat will subsequently shut down. In the event the breakers are on, you can inspect a handful of other places before calling a professional technician.
Since this error can drain your thermostat’s battery, the first step may be providing enough power to figure out if this specific error code is what you’re working with. You can separate the thermostat from its base and supply power by using a USB cable. In the event it reveals error code 195, you may continue to visually check components like 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 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 bad connection in the thermostat. The technician needs to meticulously investigate and test the Nest’s electrical system to understand where the power is surging or why the thermostat believes there’s an overcurrent problem.
Although this error code isn’t critical, it might still keep 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 missing 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 adjust the wiring itself if there is. If not, you’ll need a Nest Power Connector.
During installation of a Nest Power Connector, you may notice error code E297 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector is 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 stemming from an overcurrent. If excess power is transported through the Nest’s wiring, it can damage internal components and may 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 suggested to shut the power off as soon as you can. You can then get a hold of a professional technician with the proper experience diagnosing 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 easy as the breaker being shut 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 check the wires to make sure nothing is loose or damaged. If nothing looks to be out of place, it’s best to get in touch with a local professional.