Using a Nest thermostat is one of the easiest ways to improve the daily schedule of your HVAC system. This smart thermostat can recognize your preferences and automatically make improvements. But as you may expect, it won’t work well or at all if you see an error code appear. The specific error code provides useful information about the root of the problem, something a knowledgeable technician can use to provide solutions that much faster.
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 along with how you can solve it and the approximate cost to do so. Don't forget that while the costs will ultimately hinge on the exact Nest model, you can expect to pay around $75-$200 for repairs. This should include things like travel and labor costs along with any specific parts required to finish repairs.
e298 - Critical
This critical error code is limited to newer models of the Nest thermostat and shows up when the power is disconnected from the system. Because 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 problem 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 certified technician should inspect electrical connections and wiring until they find the source 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 will need to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not simply 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 progressively look at each wire, seeing to it that they are fully inserted into the connector with the correct amount of uncovered copper. When they find the damaged connector, it can be replaced for a new one.
e195 - Critical
This critical error code can show up when the weather outside is especially hot. The HVAC system can shut down and stop delivering power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will finally turn off. Presuming the breakers are on, you can search a few other places before calling a professional technician.
Because this error can deplete your thermostat’s battery, the first step could be supplying enough power to find out if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and deliver power with a USB cable. Assuming it presents error code 195, you may continue to visually examine components like 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 indicates an electrical issue with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is getting more power than what is safe and normal. This may stem from the breaker box, an error from the control board or because of a bad connection in the thermostat. A technician needs to meticulously examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat thinks there’s an overcurrent problem.
Even though this error code isn’t critical, it can still stop you from using the Nest thermostat like normal. 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 examine the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you’ll need a Nest Power Connector.
Due to 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 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 being delivered inside the Nest’s wiring, it may damage internal components and can even be a fire hazard. If you see this error code pop up on your Nest thermostat and want to take steps to prevent electrical damage, it’s a good idea to turn the power off as soon as possible. You can then contact a professional technician with the appropriate experience diagnosing and resolving electrical issues.
e73 - Critical
When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This might be as straightforward as the breaker being shut off, but it can also be a problem with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually examine the wires to make sure none of them are loose or damaged. If nothing appears to be out of place, it’s best to speak with a local professional.