How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the easiest ways to perfect the everyday schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make adjustments. But as you can expect, it won’t work well or at all if you see an error code appear. The exact error code supplies 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 could find on your Nest thermostat. We’ll explain the basics of each error code along with how you could fix it and the approximate cost to do so. Remember that while the price will ultimately depend on the exact Nest model, you can expect to pay about $75-$200 for repairs. This should also cover travel and labor costs along with any specific components necessary 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 detached from the system. Since this is a critical power error, the thermostat will change 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 may have disconnected or become damaged, or a disconnection may have happened further along in your electrical system. This may be the circuit breaker, fuse box or system switch. A trained technician should examine electrical connections and wiring until they uncover the root of the problem.

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring needs to be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first perform a factory reset of your thermostat to ensure it’s not simply a software error. 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, ensuring they are fully attached into the connector with the correct amount of exposed copper. After they locate the malfunctioning connector, it can be exchanged for a new one.

e195 - Critical

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

Because this error can drain your thermostat’s battery, the first step could be supplying enough power to determine if this specific error code is what you’re facing. You can disconnect the thermostat from its base and supply power through a USB cable. If it displays error code 195, you can continue to visually check components like the wiring as well as your air conditioner’s air filter or drainage system. If you can't detect anything wrong with these components, it will probably be best to contact a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical malfunction with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is experiencing more power than needed. This may stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. Your technician should meticulously investigate 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 might still prevent 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 not having one can block your Nest from getting adequate 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.

During 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 has already been installed, you’ll instead have to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.

e104 - Critical

Like error code e103, e104 is a critical error originating from an overcurrent. If excess power is being delivered inside the Nest’s wiring, it may damage internal components and could 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 a good idea to switch the power off as soon as you can. You can then get a hold of a professional technician with the proper experience identifying and fixing electrical issues.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This may be as straightforward as the breaker being turned off, but it could also be something with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure nothing is loose or damaged. If nothing looks to be out of place, it’s time to get in touch with a local professional.