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 be taught your preferences and automatically make adjustments. But as you might expect, it won’t work properly or at all if you see an error code on the display. The exact error code offers useful information about the underlying problem, something a professional technician can use to present solutions that much sooner.

Listed below are seven of the most common error codes you might find on your Nest thermostat. We’ll explain the basics of each error code along with how you could fix it and the projected cost to do so. Keep in mind that while the price will ultimately depend on the exact Nest model, you can anticipate paying between $75-$200 for repairs. This should include travel and labor costs along with any specific hardware needed to complete repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and is displayed when the power is disconnected from the system. Since this is a critical power error, the thermostat will switch to the backup battery system. The error message will remain on the screen until the problem is fixed.

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

e294 - Critical

Critical error code e294 is displayed when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not just a software error. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start checking connectors.

They’ll detach the power and progressively look at each wire, making sure they are fully inserted into the connector with the correct amount of exposed copper. Once they pinpoint the malfunctioning connector, it can be swapped for a new one.

e195 - Critical

This critical error code can show up when the weather outside is particularly hot. The HVAC system can break 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 power down. Presuming the breakers are on, you can examine a few other places before calling a professional technician.

Because this error can consume your thermostat’s battery, the first step could 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 by using a USB cable. In the event it displays error code 195, you can continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to find anything wrong with these components, it's maybe best to call a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical malfunction with your Nest thermostat. More specifically, e103 can 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 through a defective connection in the thermostat. A technician will carefully examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat is convinced there’s an overcurrent problem.

n260

Although this error code isn’t critical, it could still stop you from using the Nest thermostat how you prefer to. Error code n260 concerns the lack of a C wire or Nest Power Connector, as missing 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 adjust the wiring itself if there is. If not, you need a Nest Power Connector.

With installation of a Nest Power Connector, you will sometimes notice error code E297 be displayed. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead be required 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 originating from an overcurrent. If excess power is being delivered using the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you see this error code appear on your Nest thermostat and want to protect from electrical damage, it’s suggested to shut the power off as soon as possible. You can then get in touch with a professional technician with the appropriate experience detecting and resolving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This could be as straightforward as the breaker being shut off, but it may also be an issue with the wiring. After turning off the power to your HVAC system and thermostat, you can visually check the wires to make sure none of them are loose or damaged. If nothing looks to be out of place, it’s a good idea to contact a local professional.