How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the easiest ways to perfect the everyday schedule of your HVAC system. This smart thermostat can learn your preferences and automatically make changes. But as you may 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 root of the problem, something a professional technician can use to provide solutions that much sooner.

Let's consider seven of the most common error codes you may encounter on your Nest thermostat. We’ll review the basics of each error code along with how you can address it and the estimated cost to do so. Don't forget that while the costs will ultimately hinge on the specific Nest model, you can count on paying about $75-$200 for repairs. This should include travel and labor costs as well as any specific hardware necessary to finish repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and is displayed when the power is disconnected from the system. Because 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 dealt with.

Losing power to your Nest thermostat can be for several reasons. The wiring may have disconnected or become damaged, or a disconnection might have happened further along in your home's electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician will check 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, 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 disconnect the power and progressively check each wire, seeing to it that they are fully placed into the connector with the proper amount of uncovered copper. When they find the malfunctioning connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can appear when the weather outside is especially 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 finally shut down. Presuming the breakers are on, you can examine a few other places before contacting a professional technician.

Because this error can consume your thermostat’s battery, the first step might be supplying enough power to determine if this specific error code is what you’re working with. You can detach the thermostat from its base and deliver power through a USB cable. If it displays error code 195, you should continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to detect anything wrong with these components, it's maybe best to contact a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical error with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is experiencing 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 faulty connection in the thermostat. Your technician needs to carefully examine 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

Although this error code isn’t critical, it may still keep 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 inspect 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 will sometimes notice error code E297 be displayed. This can be remedied 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 originating from an overcurrent. If excessive power is transported using 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 guard against electrical damage, it’s recommended to turn the power off as soon as you can. You can then get in touch with a professional technician with the proper experience identifying and fixing electrical issues.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This could be as straightforward as the breaker being shut off, but it could also be an issue with the wiring. After shutting 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 appears to be out of place, it’s best to contact a local professional.