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 everyday schedule of your HVAC system. This smart thermostat can recognize 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 show up. The exact error code provides useful information about the underlying problem, something a professional technician can use to present solutions that much faster.

Let's consider 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 can address it and the approximate cost to do so. Don't forget that while the costs will ultimately hinge on the precise Nest model, you can count on paying about $75-$200 for repairs. This should also cover travel and labor costs along with any specific components required to wrap up repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and is displayed when the power is shut off. As this is a critical power error, the thermostat will change to the backup battery system. The error message will remain on display until the issue is fixed.

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

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring has to be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to ensure it’s not just a software problem. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start looking at connectors.

They’ll shut off the power and gradually inspect each wire, seeing to it that they are fully attached into the connector with the proper amount of uncovered copper. After they locate the problem connector, it can be exchanged 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 sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will eventually shut down. Presuming the breakers are on, you can check a few other places before contacting a professional technician.

Because this error can drain your thermostat’s battery, the first step may be providing enough power to figure out if this specific error code is what you’re working with. You can detach the thermostat from its base and supply power through a USB cable. In the event it reveals error code 195, you may continue to visually inspect components including 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 indicates an electrical malfunction with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is receiving more power than needed. This can stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. A technician can 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 could still prevent 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 not having one can block your Nest from getting enough 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 show up. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already 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 that's the result of an overcurrent. If excess power is transported inside the Nest’s wiring, it could damage internal components and may even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to take steps to prevent electrical damage, it’s recommended to turn the power off as soon as you can. You can then contact a professional technician with the appropriate experience diagnosing and resolving electrical damage.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not receiving power. This might be as easy as the breaker being turned off, but it may also be something with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure nothing is loose or damaged. If nothing appears to be out of place, it’s best to contact a local professional.