Operating a Nest thermostat is one of the best ways to improve the day-to-day schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make improvements. But as you might expect, it won’t work well or at all if you see an error code on the display. The specific error code offers useful information about the root of the problem, something a knowledgeable technician can use to offer solutions that much faster.

Here are seven of the most likely 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 projected cost to do so. Keep in mind that while the costs will ultimately hinge on the precise 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 hardware needed to complete repairs.

e298 – Critical

This critical error code is limited to the latest models of the Nest thermostat and appears 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 problem 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 may have appeared further along in the electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician will check 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 needs 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 simply a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin checking connectors.

They’ll detach the power and slowly look at each wire, seeing to it that they are fully placed into the connector with the correct amount of exposed copper. After they find 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 especially hot. The HVAC system can shut down and stop delivering power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will eventually turn off. In the event the breakers are on, you can inspect a few other places before calling a professional technician.

Since this error can drain your thermostat’s battery, the first step may be restoring enough power to figure out if this specific error code is what you’re facing. You can separate the thermostat from its base and deliver power with a USB cable. If 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 don’t detect anything wrong with these components, it will likely be best to contact a pro.

e103 – Critical

Another critical error code, e103 indicates an electrical problem with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is receiving more power than what is safe and normal. This will sometimes stem from the breaker box, an error from the control board or through a defective connection in the thermostat. A technician needs to carefully investigate and test the Nest’s electrical system to figure out where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it may still prevent you from using the Nest thermostat how you prefer to. Error code n260 refers to the lack of a C wire or Nest Power Connector, as not having one can block your Nest from getting sufficient power. You can examine the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you’ll need a Nest Power Connector.

Due to 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 was already installed, you’ll instead need 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 originating from an overcurrent. If too much power is being delivered through the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you see this error code pop up on your Nest thermostat and want to take steps to prevent electrical damage, it’s recommended to shut the power off as soon as you can. You can then get in touch with a professional technician with the necessary experience diagnosing and fixing electrical problems.

e73 – Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power.

This will sometimes be as easy as the breaker being turned 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 examine the wires to make sure they’re not loose or damaged. If nothing appears to be out of place, it’s time to get in touch with a local professional.