Using 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 properly 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 professional technician can use to provide solutions that much sooner.
Listed below are seven of the most frequent error codes you may encounter on your Nest thermostat. We’ll explain the basics of each error code along with how you can fix it and the approximate cost to do so. Keep in mind that while the costs will ultimately hinge on the specific Nest model, you can expect to pay about $75-$200 for repairs. This should also cover travel and labor costs on top of any specific hardware necessary to finish repairs.
e298 - Critical
This critical error code is limited to new models of the Nest thermostat and is displayed when the power is disconnected from the system. Since 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 problem is dealt with.
Losing power to your Nest thermostat can be for a number of reasons. The wiring might have disconnected or become damaged, or a disconnection might have occurred further along in your home's electrical system. This might be the circuit breaker, fuse box or system switch. A certified technician will check electrical connections and wiring until they uncover the source of the problem.
e294 - Critical
Critical error code e294 appears when your Nest thermostat’s wiring should be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to ensure 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 gradually look at each wire, seeing to it that they are fully attached into the connector with the proper amount of bare copper. Once they pinpoint the problem connector, it can be swapped for a new one.
e195 - Critical
This critical error code can surface when the weather outside is severely hot. The HVAC system can fail and stop giving power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will finally power down. Assuming 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 might be restoring enough power to find out if this specific error code is what you’re working with. You can detach the thermostat from its base and supply power through a USB cable. If it displays error code 195, you can continue to visually examine components such as the wiring as well as your air conditioner’s air filter or drainage system. If you can't detect anything wrong with these components, it will probably be best to contact a pro.
e103 - Critical
Another critical error code, e103 indicates an electrical error with your Nest thermostat. More specifically, e103 will 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 because of a bad connection in the thermostat. Your technician needs to cautiously inspect and test the Nest’s electrical system to figure out where the power is surging or why the thermostat thinks there’s an overcurrent problem.
While this error code isn’t critical, it may 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 not having one can block your Nest from obtaining sufficient power. You can check the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you’ll need a Nest Power Connector.
With installation of a Nest Power Connector, you will sometimes notice error code E297 be displayed. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been installed, you’ll instead have to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.
e104 - Critical
Like error code e103, e104 is a critical error stemming from an overcurrent. If excess power is being delivered through the Nest’s wiring, it can damage internal components and could 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 straightaway. You can then get in touch with a professional technician with the appropriate experience detecting and resolving electrical malfunctions.
e73 - Critical
When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This may be as straightforward as the breaker being shut off, but it may also be an issue with the wiring. After switching 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 looks to be out of place, it’s time to contact a local professional.