How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the easiest ways to perfect the day-to-day schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make changes. But as you can expect, it won’t work well or at all if you see an error code show up. The specific error code provides useful information about the underlying 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 find on your Nest thermostat. We’ll review the basics of each error code along with how you can fix it and the approximate cost to do so. Don't forget that while the costs will ultimately hinge on the exact Nest model, you can anticipate paying around $75-$200 for repairs. This should include travel and labor costs on top of any specific parts required to wrap up repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and shows up 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 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 could have happened further along in your home's electrical system. This may be the circuit breaker, fuse box or system switch. A knowledgeable technician should check electrical connections and wiring until they locate the source of the problem.

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring needs to 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 just a software problem. If that doesn’t work, they’ll review the wiring diagram of the thermostat and begin looking at connectors.

They’ll disconnect the power and slowly check each wire, making sure they are fully attached into the connector with the proper amount of exposed copper. Once they locate the damaged connector, it can be swapped for a new one.

e195 - Critical

This critical error code can appear when the weather outside is particularly 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 eventually turn off. Presuming the breakers are on, you can check a few other places before consulting a professional technician.

As this error can consume your thermostat’s battery, the first step might be providing enough power to find out if this specific error code is what you’re dealing with. You can detach the thermostat from its base and provide power by using a USB cable. In the event it presents error code 195, you can continue to visually inspect components like 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's maybe best to contact a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical problem 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 because of a bad connection in the thermostat. The technician can carefully investigate and test the Nest’s electrical system to determine 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 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 getting adequate power. You can examine 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 might notice error code E297 show up. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead be required 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 excessive power is transported through the Nest’s wiring, it may 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 take steps to prevent electrical damage, it’s recommended to shut the power off straightaway. You can then contact a professional technician with the appropriate experience diagnosing and resolving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power. This might be as easy as the breaker being turned off, but it can also be something with the wiring. After turning off the power to your HVAC system and thermostat, you can visually check the wires to make sure none of them are loose or damaged. If nothing appears to be out of place, it’s time to contact a local professional.