How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the most convenient ways to perfect the daily schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make adjustments. But as you may expect, it won’t work correctly or at all if you see an error code on the display. The exact error code provides useful information about the root of the problem, something a professional technician can use to offer solutions that much quicker.

Let's consider seven of the most frequent error codes you might discover on your Nest thermostat. We’ll review the basics of each error code along with how you might address it and the approximate cost to do so. Keep in mind that while the price will ultimately depend on the specific Nest model, you can anticipate paying between $75-$200 for repairs. This should include travel and labor costs on top of any specific parts needed 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 switch to the backup battery system. The error message will continue to be displayed until the issue is resolved.

Losing power to your Nest thermostat can be for a number of reasons. The wiring might have disconnected or become damaged, or a disconnection could have appeared further along in the electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician will 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 complete a factory reset of your thermostat to make sure it’s not simply a software error. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and begin checking connectors.

They’ll detach the power and slowly look at each wire, seeing to it that they are fully attached into the connector with the correct amount of bare copper. Once they find the problem connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can appear when the weather outside is severely 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 power down. Assuming the breakers are on, you can inspect a few other places before calling 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. If it presents error code 195, you may continue to visually inspect components including the wiring as well as your air conditioner’s air filter or drainage system. If you can'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 indicates an electrical error with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is getting more power than needed. This may stem from the breaker box, an error from the control board or through a bad connection in the thermostat. A technician should cautiously investigate and test the Nest’s electrical system to figure out where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

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

Just like error code e103, e104 is a critical error stemming from an overcurrent. If excessive power is transported inside the Nest’s wiring, it can 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 guard against electrical damage, it’s a good idea to turn the power off as soon as you can. You can then contact a professional technician with the necessary experience identifying and solving electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This could be as straightforward as the breaker being shut off, but it can also be an issue with the wiring. After switching off the power to your HVAC system and thermostat, you can visually examine the wires to make sure they’re not loose or damaged. If nothing seems to be out of place, it’s best to get in touch with a local professional.