How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the most convenient ways to improve 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 properly or at all if you see an error code show up. The exact error code offers useful information about the root of the problem, something a professional technician can use to offer solutions that much quicker.

Let's consider seven of the most common error codes you could encounter on your Nest thermostat. We’ll explain the basics of each error code along with how you can fix it and the estimated cost to do so. Don't forget that while the price will ultimately be dependent on the exact Nest model, you can expect to pay about $75-$200 for repairs. This should include things like travel and labor costs as well as any specific components needed to complete repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and shows up when the power is detached from the system. As 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 numerous reasons. The wiring may have disconnected or become damaged, or a disconnection might have happened further along in the electrical system. This might be the circuit breaker, fuse box or system switch. A professional technician can 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 needs 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 simply a software issue. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start looking at connectors.

They’ll disconnect the power and slowly check each wire, seeing to it that they are fully inserted into the connector with the correct amount of uncovered copper. Once they find the problem connector, it can be replaced for a new one.

e195 - Critical

This critical error code can surface when the weather outside is particularly hot. The HVAC system can shut down and stop sending power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat depletes and the thermostat will finally turn off. Assuming the breakers are on, you can inspect a handful of other places before contacting a professional technician.

Since this error can consume your thermostat’s battery, the first step may be restoring enough power to figure out if this specific error code is what you’re working with. You can separate the thermostat from its base and supply power by using a USB cable. In the event it displays 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 uncover anything wrong with these components, it's maybe best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 indicates 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 needed. This may stem from the breaker box, an error from the control board or because of a bad connection in the thermostat. Your technician should cautiously examine and test the Nest’s electrical system to understand where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Although this error code isn’t critical, it might still keep you from using the Nest thermostat how you want to. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining enough power. You can check the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you can get a Nest Power Connector.

Due to installation of a Nest Power Connector, you might notice error code E297 show up. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been installed, you’ll instead be required 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 too much power is transported through the Nest’s wiring, it could 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 take steps to prevent electrical damage, it’s recommended to switch the power off straightaway. You can then contact a professional technician with the necessary experience diagnosing and fixing electrical problems.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This could be as straightforward as the breaker being switched off, but it could also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually examine the wires to make sure nothing is loose or damaged. If nothing looks to be out of place, it’s best to speak with a local professional.