How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the easiest ways to optimize the day-to-day schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make changes. But as you might expect, it won’t work well or at all if you see an error code appear. The specific error code offers useful information about the source of the problem, something a professional technician can use to provide solutions that much quicker.

Let's consider seven of the most frequent error codes you may encounter on your Nest thermostat. We’ll explain the basics of each error code as well as how you can fix it and the approximate cost to do so. Keep in mind that while the costs will ultimately be dependent on the precise Nest model, you can count on paying around $75-$200 for repairs. This should also cover travel and labor costs on top of any specific parts necessary to wrap up repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and shows up when the power is disconnected from the system. Because 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 dealt with.

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 home's electrical system. This may be the circuit breaker, fuse box or system switch. A trained technician can inspect 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 should reconfigure the R wire. They’ll first perform a factory reset of your thermostat to make sure it’s not merely a software issue. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start looking at connectors.

They’ll detach the power and progressively inspect each wire, seeing to it that they are fully placed into the connector with the correct amount of bare copper. Once they locate the problem connector, it can be replaced for a new one.

e195 - Critical

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

As this error can drain your thermostat’s battery, the first step could be supplying enough power to figure out if this specific error code is what you’re facing. You can separate the thermostat from its base and supply power through a USB cable. Assuming it presents error code 195, you should continue to visually check 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 will probably 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 can refer to an overcurrent problem, which means the wiring is receiving more power than necessary. This can stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. Your technician should meticulously 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 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 not having one can block your Nest from receiving enough power. You can examine 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.

During installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be remedied 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

Similar to error code e103, e104 is a critical error stemming from an overcurrent. If excessive power is sent inside 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 guard against electrical damage, it’s recommended to switch the power off straightaway. You can then contact a professional technician with the appropriate experience diagnosing and resolving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This may be as straightforward as the breaker being turned off, but it may also be something with the wiring. After shutting 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 appears to be out of place, it’s time to speak with a local professional.