How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating 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 may expect, it won’t work properly or at all if you see an error code show up. The specific error code offers useful information about the source of the problem, something a professional technician can use to present solutions that much faster.

Listed below are seven of the most common error codes you might encounter on your Nest thermostat. We’ll explain the basics of each error code along with how you could fix it and the estimated cost to do so. Remember that while the costs will ultimately be dependent on the exact Nest model, you can anticipate paying about $75-$200 for repairs. This should include things like travel and labor costs on top of any specific parts necessary to finish repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and appears when the power is shut off. As this is a critical power error, the thermostat will swap to the backup battery system. The error message will remain on the screen until the problem is dealt with.

Losing power to your Nest thermostat can be for numerous 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 certified technician can check electrical connections and wiring until they uncover the source of the problem.

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to make sure it’s not just a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin inspecting connectors.

They’ll disconnect the power and gradually check each wire, making sure they are fully inserted into the connector with the correct amount of bare copper. After they pinpoint the problem connector, it can be swapped for a new one.

e195 - Critical

This critical error code can surface when the weather outside is particularly hot. The HVAC system can fail and stop delivering power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will eventually shut down. Presuming the breakers are on, you can inspect a couple of other places before calling a professional technician.

Because this error can consume your thermostat’s battery, the first step might be providing enough power to figure out if this specific error code is what you’re working with. You can disconnect the thermostat from its base and provide power through a USB cable. In the event it reveals 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 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 indicates an electrical issue with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is experiencing more power than what is safe and normal. This may stem from the breaker box, an error from the control board or through a defective connection in the thermostat. Your technician needs to carefully examine and test the Nest’s electrical system to understand where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

While this error code isn’t critical, it could still prevent you from using the Nest thermostat how you prefer to. Error code n260 concerns the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining enough power. You can check the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you’ll need a Nest Power Connector.

Due to installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be dealt with 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 excess power is being delivered inside 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 take steps to prevent electrical damage, it’s a good idea to shut the power off straightaway. You can then get in touch with a professional technician with the necessary experience identifying and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not receiving power. This will sometimes be as straightforward as the breaker being switched off, but it may also be something with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure they’re not loose or damaged. If nothing looks to be out of place, it’s best to get in touch with a local professional.