How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the best ways to improve the daily schedule of your HVAC system. This smart thermostat can recognize your preferences and automatically make improvements. But as you may expect, it won’t work properly or at all if you see an error code on the display. The precise error code supplies useful information about the underlying problem, something a knowledgeable technician can use to provide solutions that much sooner.

Listed below are seven of the most frequent error codes you could find on your Nest thermostat. We’ll walk you through the basics of each error code as well as how you might fix it and the estimated cost to do so. Don't forget that while the price will ultimately hinge on the exact Nest model, you can expect to pay around $75-$200 for repairs. This should include things like travel and labor costs along with any specific hardware necessary to finish repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and is displayed when the power is shut off. Since this is a critical power error, the thermostat will change to the backup battery system. The error message will continue to be displayed until the problem is fixed.

Losing power to your Nest thermostat can be for numerous reasons. The wiring could have disconnected or become damaged, or a disconnection may have appeared further along in your home's electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician should check 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 should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not simply a software problem. 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 progressively inspect each wire, seeing to it that they are fully placed into the connector with the proper amount of exposed copper. After they find the damaged connector, it can be swapped for a new one.

e195 - Critical

This critical error code can appear when the weather outside is especially hot. The HVAC system can break down and stop delivering power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat depletes and the thermostat will finally turn off. In the event the breakers are on, you can search a couple of other places before contacting a professional technician.

Because this error can drain your thermostat’s battery, the first step may be restoring enough power to determine if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and supply power with a USB cable. In the event it presents error code 195, you can continue to visually check components such as the wiring as well as your air conditioner’s air filter or drainage system. If you don’t uncover 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 can 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 bad connection in the thermostat. The technician needs to cautiously investigate and test the Nest’s electrical system to determine where the power is surging or why the thermostat is convinced there’s an overcurrent problem.

n260

Although this error code isn’t critical, it could still keep you from using the Nest thermostat how you want to. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as not having one can block your Nest from getting adequate 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.

During 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 has already been 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 originating from an overcurrent. If excess power is being delivered through the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to guard against electrical damage, it’s recommended to shut the power off as soon as you can. You can then get in touch with a professional technician with the necessary experience diagnosing and resolving electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This might be as simple as the breaker being turned off, but it can also be an issue with the wiring. After shutting 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 seems to be out of place, it’s a good idea to speak with a local professional.