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 everyday schedule of your heating and cooling. This smart thermostat can recognize your preferences and automatically make improvements. But as you might expect, it won’t work properly or at all if you see an error code show up. The precise error code supplies 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 discover on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you could fix it and the projected cost to do so. Keep in mind that while the price will ultimately hinge on the exact Nest model, you can count on paying around $75-$200 for repairs. This should include travel and labor costs along with any specific parts required to wrap up repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and appears when the power is disconnected from the system. Because this is a critical power error, the thermostat will switch to the backup battery system. The error message will continue to be displayed until the issue is fixed.

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

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring should 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 merely a software problem. If that doesn’t work, they’ll review the wiring diagram of the thermostat and begin inspecting connectors.

They’ll shut off the power and slowly look at each wire, seeing to it that they are fully attached into the connector with the proper amount of uncovered copper. Once they pinpoint the problem connector, it can be swapped for a new one.

e195 - Critical

This critical error code can appear when the weather outside is especially hot. The HVAC system can shut down and stop delivering power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will eventually power down. Presuming the breakers are on, you can examine a couple of other places before contacting a professional technician.

Because this error can consume your thermostat’s battery, the first step might be providing enough power to determine if this specific error code is what you’re facing. You can detach the thermostat from its base and supply power through a USB cable. If it displays error code 195, you may 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 will likely be best to call a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical problem 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 because of a bad connection in the thermostat. A technician will 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 may still prevent you from using the Nest thermostat like normal. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from receiving sufficient power. You can check the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you can get a Nest Power Connector.

During installation of a Nest Power Connector, you may notice error code E297 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been installed, you’ll instead have 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 stemming from an overcurrent. If excessive power is transported inside the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you notice this error code show up on your Nest thermostat and want to guard against electrical damage, it’s suggested to shut the power off straightaway. You can then contact a professional technician with the proper experience detecting and fixing electrical damage.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not receiving power. This may be as easy as the breaker being shut off, but it can also be a problem with the wiring. After turning off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure none of them are loose or damaged. If nothing seems to be out of place, it’s best to contact a local professional.