How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the most convenient ways to perfect the day-to-day schedule of your heating and cooling. This smart thermostat can learn your preferences and automatically make changes. But as you may expect, it won’t work well or at all if you see an error code appear. The specific error code supplies useful information about the underlying problem, something a knowledgeable technician can use to present solutions that much sooner.

Here are seven of the most frequent error codes you could encounter on your Nest thermostat. We’ll walk you through the basics of each error code along with how you might address it and the approximate cost to do so. Keep in mind that while the price will ultimately be dependent on the precise Nest model, you can count on paying between $75-$200 for repairs. This should include things like travel and labor costs along with any specific components necessary to finish repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and appears when the power is disconnected from the system. As 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 issue is resolved.

Losing power to your Nest thermostat can be for numerous reasons. The wiring might have disconnected or become damaged, or a disconnection may have happened further along in the electrical system. This could be the circuit breaker, fuse box or system switch. A professional technician can inspect electrical connections and wiring until they uncover the source of the problem.

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to make sure it’s not simply a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin inspecting connectors.

They’ll disconnect the power and slowly check each wire, making sure they are fully inserted into the connector with the correct amount of exposed copper. When they find the problem connector, it can be swapped for a new one.

e195 - Critical

This critical error code can surface when the weather outside is particularly hot. The HVAC system can fail and stop sending power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat depletes and the thermostat will eventually turn off. Assuming the breakers are on, you can search a handful of other places before contacting a professional technician.

As this error can deplete your thermostat’s battery, the first step could be restoring enough power to figure out if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and supply power by using a USB cable. If it displays error code 195, you should continue to visually inspect components such as the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to uncover anything wrong with these components, it will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical error with your Nest thermostat. More specifically, e103 can 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 thanks to a defective connection in the thermostat. The technician will carefully inspect and test the Nest’s electrical system to figure out where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

While this error code isn’t critical, it can still keep you from using the Nest thermostat how you prefer to. Error code n260 concerns the lack of a C wire or Nest Power Connector, as missing one can block your Nest from receiving enough power. You can examine 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.

With 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 has already been installed, you’ll instead need 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 too much power is being delivered using the Nest’s wiring, it may damage internal components and may 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 switch the power off as soon as you can. You can then get in touch with a professional technician with the appropriate experience identifying and resolving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not receiving power. This may be as simple as the breaker being shut off, but it could also be a problem with the wiring. After switching off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure they’re not loose or damaged. If nothing seems to be out of place, it’s a good idea to get in touch with a local professional.