How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the easiest ways to improve the everyday schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make improvements. But as you may expect, it won’t work well or at all if you see an error code show up. The specific error code provides useful information about the root of the problem, something a trained technician can use to offer solutions that much quicker.

Listed below are seven of the most likely error codes you might discover on your Nest thermostat. We’ll review the basics of each error code as well as how you could 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 around $75-$200 for repairs. This should include things like travel and labor costs on top of any specific hardware necessary to finish repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and shows up when the power is shut off. Because this is a critical power error, the thermostat will switch 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 several reasons. The wiring might have disconnected or become damaged, or a disconnection could have occurred further along in your electrical system. This might be the circuit breaker, fuse box or system switch. A professional technician will inspect electrical connections and wiring until they uncover the source of the problem.

e294 - Critical

Critical error code e294 is displayed 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 ensure it’s not just a software problem. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start looking at connectors.

They’ll detach the power and slowly check each wire, making sure they are fully inserted into the connector with the proper amount of uncovered copper. When they find the problem connector, it can be swapped 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 sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will subsequently shut down. Assuming the breakers are on, you can inspect a few other places before consulting a professional technician.

As this error can consume your thermostat’s battery, the first step may be restoring 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 by using a USB cable. Assuming it displays error code 195, you may continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you don’t find anything wrong with these components, it will likely be best to contact a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical problem with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is getting more power than what is safe and normal. This can stem from the breaker box, an error from the control board or because of a defective connection in the thermostat. The technician can carefully examine 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

Even though this error code isn’t critical, it may still keep 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 receiving sufficient power. You can inspect the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you’ll need a Nest Power Connector.

With installation of a Nest Power Connector, you will sometimes notice error code E297 show up. This can be resolved 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 that's the result of an overcurrent. If excessive power is transported using the Nest’s wiring, it can damage internal components and could 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 suggested to turn the power off as soon as possible. You can then get a hold of a professional technician with the appropriate experience detecting and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This may be as simple as the breaker being switched off, but it can also be something 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 looks to be out of place, it’s best to contact a local professional.