How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the best ways to improve the everyday schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make changes. But as you might expect, it won’t work properly or at all if you see an error code appear. The exact error code offers useful information about the underlying problem, something a trained technician can use to provide solutions that much quicker.

Listed below are seven of the most frequent error codes you may find on your Nest thermostat. We’ll walk you through the basics of each error code along with how you could address it and the projected cost to do so. Remember that while the costs will ultimately hinge on the specific Nest model, you can count on paying between $75-$200 for repairs. This should include things like travel and labor costs as well as any specific parts required to wrap up repairs.

e298 - Critical

This critical error code is limited to newer 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 dealt with.

Losing power to your Nest thermostat can be for several reasons. The wiring might have disconnected or become damaged, or a disconnection may have appeared further along in your home's electrical system. This might be the circuit breaker, fuse box or system switch. A certified 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 has to be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to make sure it’s not merely 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 gradually inspect each wire, making sure they are fully placed into the connector with the correct amount of bare copper. Once they locate the damaged connector, it can be replaced for a new one.

e195 - Critical

This critical error code can show up when the weather outside is severely hot. The HVAC system can break down and stop giving power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will finally turn off. In the event the breakers are on, you can inspect a handful of other places before calling a professional technician.

Because this error can deplete your thermostat’s battery, the first step might be providing enough power to determine if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and provide power with a USB cable. If it presents error code 195, you can continue to visually examine components such as the wiring as well as your air conditioner’s air filter or drainage system. If you can't find anything wrong with these components, it will likely be best to call a pro.

e103 - Critical

Another critical error code, e103 signifies 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 needed. This can stem from the breaker box, an error from the control board or because of a defective connection in the thermostat. A technician will meticulously examine and test the Nest’s electrical system to figure out where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

Although this error code isn’t critical, it might still prevent you from using the Nest thermostat like normal. Error code n260 concerns 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.

Due to installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead have to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.

e104 - Critical

Similar to error code e103, e104 is a critical error stemming from an overcurrent. If too much power is sent through the Nest’s wiring, it may damage internal components and can even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to take steps to prevent electrical damage, it’s a good idea to shut the power off straightaway. You can then get in touch with a professional technician with the appropriate experience diagnosing and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This will sometimes be as straightforward as the breaker being switched off, but it may also be something with the wiring. After turning off the power to your HVAC system and thermostat, you can visually examine the wires to make sure they’re not loose or damaged. If nothing appears to be out of place, it’s a good idea to contact a local professional.