How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the best ways to optimize the day-to-day schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make adjustments. But as you might expect, it won’t work well or at all if you see an error code on the display. The precise error code provides useful information about the source of the problem, something a professional technician can use to present solutions that much faster.

Let's consider seven of the most common error codes you might find on your Nest thermostat. We’ll explain the basics of each error code as well as how you might fix it and the projected cost to do so. Don't forget 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 also cover travel and labor costs on top of any specific hardware needed 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 shut off. As this is a critical power error, the thermostat will switch to the backup battery system. The error message will remain on display until the problem is resolved.

Losing power to your Nest thermostat can be for a number of reasons. The wiring might have disconnected or become damaged, or a disconnection could have appeared further along in your electrical system. This may be the circuit breaker, fuse box or system switch. A knowledgeable technician can check electrical connections and wiring until they locate the root of the problem.

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring has to be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not just a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start inspecting connectors.

They’ll shut off the power and slowly check each wire, making sure they are fully attached into the connector with the proper amount of bare copper. After they pinpoint the problem connector, it can be replaced for a new one.

e195 - Critical

This critical error code can show up when the weather outside is particularly hot. The HVAC system can fail and stop delivering power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will eventually turn off. Presuming the breakers are on, you can check a few other places before contacting a professional technician.

Because this error can consume your thermostat’s battery, the first step could be supplying enough power to figure out if this specific error code is what you’re facing. You can separate the thermostat from its base and supply power through a USB cable. In the event 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 don’t find anything wrong with these components, it's maybe best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical issue with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is experiencing more power than needed. This will sometimes stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. The technician should meticulously investigate and test the Nest’s electrical system to understand where the power is surging or why the thermostat is convinced there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it might still prevent you from using the Nest thermostat how you want to. 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 obtaining adequate 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.

Due to installation of a Nest Power Connector, you will sometimes notice error code E297 show up. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been installed, you’ll instead be required 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 originating from an overcurrent. If too much power is transported inside the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to protect from electrical damage, it’s a good idea to switch the power off as soon as you can. You can then contact a professional technician with the proper experience detecting and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This may be as easy as the breaker being turned off, but it could also be an issue with the wiring. After turning 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 best to contact a local professional.