Using a Nest thermostat is one of the easiest ways to optimize the day-to-day schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make improvements. But as you may expect, it won’t work correctly or at all if you see an error code show up. The exact error code offers useful information about the underlying problem, something a professional technician can use to offer solutions that much quicker.

Listed below are seven of the most likely error codes you may discover on your Nest thermostat. We’ll walk you through the basics of each error code along with how you can fix it and the projected cost to do so. Keep in mind that while the price will ultimately be dependent on the specific Nest model, you can anticipate paying around $75-$200 for repairs. This should include things like travel and labor costs on top of any specific parts necessary to wrap up repairs.

e298 – Critical

This critical error code is limited to new models of the Nest thermostat and is displayed when the power is disconnected from the system. As this is a critical power error, the thermostat will change to the backup battery system. The error message will remain on the screen until the issue is dealt with.

Losing power to your Nest thermostat can be for a number of reasons. The wiring could have disconnected or become damaged, or a disconnection might have happened further along in your home’s electrical system. This could be the circuit breaker, fuse box or system switch. A certified technician should check electrical connections and wiring until they locate the source of the problem.

e294 – Critical

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

They’ll disconnect the power and progressively check each wire, making sure they are fully placed into the connector with the correct amount of exposed copper. Once they find the malfunctioning connector, it can be replaced for a new one.

e195 – Critical

This critical error code can appear when the weather outside is particularly hot. The HVAC system can fail and stop sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will finally power down. Presuming the breakers are on, you can inspect a few other places before consulting a professional technician.

As this error can deplete 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 detach the thermostat from its base and supply power through a USB cable. If it reveals error code 195, you should continue to visually inspect components such as the wiring as well as your air conditioner’s air filter or drainage system. If you don’t find anything wrong with these components, it will likely be best to get in touch with a pro.

e103 – Critical

Another critical error code, e103 suggests an electrical error 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 through a bad connection in the thermostat. A technician should carefully inspect and test the Nest’s electrical system to determine where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

While this error code isn’t critical, it may still prevent you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from receiving 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 can get a Nest Power Connector.

With installation of a Nest Power Connector, you may notice error code E297 be displayed. 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

Similar to error code e103, e104 is a critical error originating from an overcurrent. If excessive power is being delivered using the Nest’s wiring, it may damage internal components and can even be a fire hazard. If you see this error code pop up on your Nest thermostat and want to protect from electrical damage, it’s recommended to shut the power off as soon as you can. You can then get a hold of a professional technician with the necessary experience diagnosing and fixing electrical damage.

e73 – Critical

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

This might be as simple as the breaker being switched off, but it could also be something with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually check 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.