How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the most convenient ways to improve the daily schedule of your HVAC system. This smart thermostat can be taught 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 on the display. The precise error code provides useful information about the underlying problem, something a professional technician can use to offer solutions that much quicker.

Here are seven of the most frequent error codes you might discover on your Nest thermostat. We’ll walk you through the basics of each error code as well as how you can address it and the estimated cost to do so. Don't forget that while the costs will ultimately be dependent on the exact Nest model, you can anticipate paying around $75-$200 for repairs. This should include things like travel and labor costs along with any specific parts required to wrap up repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and appears when the power is shut off. Since this is a critical power error, the thermostat will change to the backup battery system. The error message will remain on display until the problem is fixed.

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 the electrical system. This could be the circuit breaker, fuse box or system switch. A knowledgeable technician can examine 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 should 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 problem. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin checking connectors.

They’ll shut off the power and slowly look at each wire, ensuring they are fully attached into the connector with the proper amount of bare copper. Once they find the damaged connector, it can be exchanged 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 delivering power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will subsequently turn off. Assuming the breakers are on, you can examine a few other places before consulting a professional technician.

As this error can drain your thermostat’s battery, the first step may 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 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 don’t uncover anything wrong with these components, it's maybe best to call a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical issue with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is experiencing more power than necessary. This may stem from the breaker box, an error from the control board or because of a defective connection in the thermostat. A technician can cautiously examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

While this error code isn’t critical, it could still stop you from using the Nest thermostat how you want to. Error code n260 concerns the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining adequate 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 need a Nest Power Connector.

During installation of a Nest Power Connector, you might notice error code E297 show up. This can be dealt with 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

Just like error code e103, e104 is a critical error that's the result of 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 see this error code show up on your Nest thermostat and want to protect from electrical damage, it’s recommended to shut the power off straightaway. You can then get a hold of a professional technician with the appropriate experience detecting and solving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This may be as simple as the breaker being turned off, but it may also be an issue with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually examine the wires to make sure nothing is loose or damaged. If nothing appears to be out of place, it’s a good idea to speak with a local professional.