Installing a Nest thermostat is one of the best ways to optimize the daily schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make improvements. But as you can expect, it won’t work correctly or at all if you see an error code appear. The precise error code offers useful information about the underlying problem, something a knowledgeable technician can use to present solutions that much sooner.
Here are seven of the most likely error codes you might find on your Nest thermostat. We’ll explain the basics of each error code on top of how you might fix it and the projected cost to do so. Remember that while the price will ultimately be dependent on the exact Nest model, you can count on paying around $75-$200 for repairs. This should also cover travel and labor costs on top of any specific parts required 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 disconnected from the system. Because this is a critical power error, the thermostat will swap to the backup battery system. The error message will remain on the screen until the problem is resolved.
Losing power to your Nest thermostat can be for several reasons. The wiring could have disconnected or become damaged, or a disconnection could have occurred further along in your home's electrical system. This might be the circuit breaker, fuse box or system switch. A trained technician should examine 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 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 ensure it’s not just a software issue. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start looking at connectors.
They’ll shut off the power and progressively check each wire, making sure they are fully placed into the connector with the correct amount of exposed copper. When they find 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 particularly hot. The HVAC system can shut down and stop sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will eventually power down. Assuming the breakers are on, you can check a handful of other places before calling a professional technician.
Because this error can drain your thermostat’s battery, the first step could 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 with a USB cable. In the event it displays error code 195, you can continue to visually examine components including 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 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 experiencing more power than necessary. This will sometimes stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. Your technician needs to carefully inspect and test the Nest’s electrical system to understand where the power is surging or why the thermostat believes there’s an overcurrent problem.
Even though this error code isn’t critical, it might still prevent 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 receiving sufficient power. You can examine the Nest’s C connector for the presence of a C wire and adjust the wiring itself if there is. If not, you need a Nest Power Connector.
Due to installation of a Nest Power Connector, you might notice error code E297 appear. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already 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 that's the result of an overcurrent. If excessive power is being delivered through the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you see this error code show up on your Nest thermostat and want to take steps to prevent 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 necessary experience detecting and fixing electrical damage.
e73 - Critical
When your thermostat displays error code e73, it means that the Rc wire is not getting power. This will sometimes be as simple as the breaker being turned off, but it may also be something with the wiring. After turning off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure none of them are loose or damaged. If nothing appears to be out of place, it’s time to speak with a local professional.