How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the most convenient ways to improve the everyday schedule of your comfort system. 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 precise error code offers useful information about the source of the problem, something a professional technician can use to provide solutions that much sooner.

Listed below are seven of the most common error codes you could encounter on your Nest thermostat. We’ll explain the basics of each error code as well as how you can address it and the projected cost to do so. Don't forget that while the costs will ultimately depend on the precise Nest model, you can expect to pay between $75-$200 for repairs. This should also cover travel and labor costs as well as any specific components necessary to complete repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and is displayed when the power is detached from the system. Since 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 issue is fixed.

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

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to ensure it’s not merely a software problem. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin looking at connectors.

They’ll detach the power and progressively look at each wire, seeing to it that they are fully placed into the connector with the correct amount of exposed copper. After they locate the problem connector, it can be swapped for a new one.

e195 - Critical

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

Because this error can consume your thermostat’s battery, the first step could be restoring enough power to figure out if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and deliver power with a USB cable. In the event it reveals error code 195, you should continue to visually inspect components including the wiring as well as your air conditioner’s air filter or drainage system. If you don’t uncover 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 issue with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is receiving more power than what is safe and normal. This can stem from the breaker box, an error from the control board or through a defective connection in the thermostat. Your technician needs to cautiously 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

Although this error code isn’t critical, it can still prevent you from using the Nest thermostat how you want to. Error code n260 concerns the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining sufficient 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’ll need a Nest Power Connector.

During installation of a Nest Power Connector, you might notice error code E297 show up. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been 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 that's the result of an overcurrent. If excessive power is sent using the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to guard against electrical damage, it’s recommended to switch the power off straightaway. You can then get in touch with a professional technician with the appropriate experience identifying and resolving electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This will sometimes be as straightforward as the breaker being shut off, but it may also be something with the wiring. After switching 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 appears to be out of place, it’s a good idea to contact a local professional.