How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the easiest ways to perfect the daily schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make changes. But as you might expect, it won’t work correctly or at all if you see an error code appear. The exact error code offers useful information about the underlying problem, something a knowledgeable technician can use to present solutions that much quicker.

Let's consider seven of the most frequent error codes you might discover on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you can address it and the projected cost to do so. Keep in mind that while the costs 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 along with any specific hardware required to complete repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and appears when the power is detached from the system. Since 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 resolved.

Losing power to your Nest thermostat can be for a number of reasons. The wiring could have disconnected or become damaged, or a disconnection could have occurred further along in the electrical system. This may be the circuit breaker, fuse box or system switch. A trained technician can check 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, you’ll need the technician to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to make sure it’s not just a software issue. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start looking at connectors.

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

e195 - Critical

This critical error code can show up when the weather outside is especially hot. The HVAC system can fail and stop sending power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will eventually turn off. Presuming the breakers are on, you can inspect a handful of other places before consulting a professional technician.

As this error can deplete 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 deliver power by using a USB cable. In the event it presents error code 195, you can continue to visually inspect components including the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to detect anything wrong with these components, it will likely be best to contact a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical problem with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is getting more power than necessary. This will sometimes stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. A technician can cautiously examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it might 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 not having 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 can get a Nest Power Connector.

During installation of a Nest Power Connector, you may notice error code E297 be displayed. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already 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 that's the result of an overcurrent. If excess 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 appear on your Nest thermostat and want to take steps to prevent electrical damage, it’s suggested to turn the power off as soon as possible. You can then contact a professional technician with the proper experience detecting and resolving electrical damage.

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 switched off, but it may also be an issue with the wiring. After turning off the power to your HVAC system and thermostat, you can visually examine the wires to make sure none of them are loose or damaged. If nothing looks to be out of place, it’s a good idea to get in touch with a local professional.