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 optimize the day-to-day schedule of your comfort system. This smart thermostat can be taught your preferences and automatically make improvements. But as you can expect, it won’t work correctly or at all if you see an error code on the display. The specific error code provides useful information about the root of the problem, something a professional technician can use to provide solutions that much faster.

Listed below are seven of the most common error codes you could encounter on your Nest thermostat. We’ll review the basics of each error code along with how you could solve it and the estimated cost to do so. Don't forget that while the price will ultimately hinge on the precise Nest model, you can count on paying between $75-$200 for repairs. This should also cover travel and labor costs as well as any specific parts required to finish repairs.

e298 - Critical

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

Losing power to your Nest thermostat can be for a number of reasons. The wiring might have disconnected or become damaged, or a disconnection may have occurred further along in your home's electrical system. This may be the circuit breaker, fuse box or system switch. A certified technician will examine 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 should be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not just a software problem. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start looking at connectors.

They’ll detach the power and slowly inspect each wire, ensuring they are fully placed into the connector with the proper amount of bare copper. Once they pinpoint the damaged connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can appear when the weather outside is particularly hot. The HVAC system can break down and stop giving power to your Nest thermostat. When this problem persists, the backup battery in your thermostat drains and the thermostat will subsequently turn off. Assuming the breakers are on, you can examine a handful of other places before calling a professional technician.

As this error can consume your thermostat’s battery, the first step might be supplying enough power to determine if this specific error code is what you’re facing. You can disconnect the thermostat from its base and supply power by using a USB cable. Assuming it displays error code 195, you may continue to visually examine components such as 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 probably be best to call a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical issue with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is getting more power than what is safe and normal. This will sometimes stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. A technician can cautiously 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

While this error code isn’t critical, it can 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 the absence of one can block your Nest from obtaining adequate power. You can check 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 may notice error code E297 show up. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector is 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 originating from an overcurrent. If excess power is sent inside the Nest’s wiring, it can damage internal components and can 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 a good idea to turn the power off as soon as possible. You can then contact a professional technician with the proper experience identifying and fixing electrical problems.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This might be as straightforward as the breaker being shut off, but it can also be an issue with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually check 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 speak with a local professional.