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 day-to-day schedule of your heating and cooling. This smart thermostat can recognize your preferences and automatically make adjustments. But as you might expect, it won’t work properly or at all if you see an error code on the display. The exact error code provides useful information about the underlying problem, something a knowledgeable technician can use to provide solutions that much faster.

Listed below are seven of the most frequent error codes you might discover on your Nest thermostat. We’ll review the basics of each error code on top of how you can fix it and the estimated cost to do so. Don't forget that while the price will ultimately depend on the specific Nest model, you can expect to pay about $75-$200 for repairs. This should include things like travel and labor costs as well as 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 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 display until the issue is resolved.

Losing power to your Nest thermostat can be for numerous reasons. The wiring might have disconnected or become damaged, or a disconnection may have appeared further along in your electrical system. This may be the circuit breaker, fuse box or system switch. A certified technician can inspect electrical connections and wiring until they find the root of the problem.

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring needs to 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 simply a software issue. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and begin inspecting connectors.

They’ll disconnect the power and slowly look at each wire, ensuring they are fully inserted into the connector with the correct amount of uncovered copper. After they pinpoint the damaged connector, it can be replaced for a new one.

e195 - Critical

This critical error code can show up when the weather outside is particularly hot. The HVAC system can fail and stop giving power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will subsequently shut down. Presuming the breakers are on, you can check a few other places before contacting a professional technician.

Since this error can drain your thermostat’s battery, the first step might be supplying enough power to determine if this specific error code is what you’re facing. You can detach the thermostat from its base and deliver power through a USB cable. Assuming it reveals 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 uncover anything wrong with these components, it will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical malfunction with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is receiving more power than needed. This may stem from the breaker box, an error from the control board or through a faulty connection in the thermostat. The technician can cautiously 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 could still stop you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as the absence of one can block your Nest from obtaining adequate 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.

Due to 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 is 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 originating from an overcurrent. If excess power is transported through the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you see this error code appear on your Nest thermostat and want to take steps to prevent electrical damage, it’s recommended 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 indicates that the Rc wire is not getting power. This may be as simple as the breaker being turned 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 looks to be out of place, it’s best to speak with a local professional.