Operating a Nest thermostat is one of the best ways to optimize the everyday schedule of your HVAC system. This smart thermostat can learn your preferences and automatically make adjustments. But as you may expect, it won’t work properly or at all if you see an error code appear. The exact error code offers 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 find on your Nest thermostat. We’ll review the basics of each error code along with how you could fix it and the estimated cost to do so. Remember that while the price will ultimately be dependent on the specific Nest model, you can expect to pay around $75-$200 for repairs. This should include travel and labor costs as well as any specific components required 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 change to the backup battery system. The error message will continue to be displayed until the problem is dealt with.
Losing power to your Nest thermostat can be for several reasons. The wiring may have disconnected or become damaged, or a disconnection may have happened further along in the electrical system. This might be the circuit breaker, fuse box or system switch. A professional technician can examine electrical connections and wiring until they uncover the root of the problem.
e294 - Critical
Critical error code e294 is displayed when your Nest thermostat’s wiring should be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to make sure it’s not simply a software issue. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin inspecting connectors.
They’ll shut off the power and slowly check each wire, making sure they are fully attached into the connector with the correct amount of exposed copper. After they pinpoint the malfunctioning connector, it can be replaced for a new one.
e195 - Critical
This critical error code can surface 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 subsequently power down. Assuming the breakers are on, you can search a handful of other places before contacting a professional technician.
Because this error can deplete your thermostat’s battery, the first step could be providing enough power to determine if this specific error code is what you’re working with. You can disconnect the thermostat from its base and supply power through a USB cable. Assuming it presents error code 195, you should continue to visually examine components like the wiring as well as your air conditioner’s air filter or drainage system. If you can't find anything wrong with these components, it will likely be 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 will refer to an overcurrent problem, which means the wiring is receiving more power than necessary. This will sometimes stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. A technician should cautiously 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 might still prevent 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 not having 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 adapt 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 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead have 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 originating from an overcurrent. If excess power is transported inside the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you see this error code appear on your Nest thermostat and want to protect from electrical damage, it’s suggested to shut the power off as soon as you can. You can then contact a professional technician with the appropriate experience detecting and fixing 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 simple as the breaker being shut off, but it may 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 seems to be out of place, it’s a good idea to get in touch with a local professional.