How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the most convenient ways to optimize the day-to-day schedule of your HVAC system. This smart thermostat can learn your preferences and automatically make changes. But as you can expect, it won’t work well 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 trained technician can use to present solutions that much faster.

Here are seven of the most frequent error codes you might find on your Nest thermostat. We’ll explain the basics of each error code as well as how you could address it and the estimated cost to do so. Don't forget that while the price will ultimately be dependent on the precise Nest model, you can expect to pay between $75-$200 for repairs. This should include things like travel and labor costs along with any specific components required to finish repairs.

e298 - Critical

This critical error code is limited to newer 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 remain on the screen until the issue is resolved.

Losing power to your Nest thermostat can be for numerous reasons. The wiring may have disconnected or become damaged, or a disconnection might have appeared further along in your electrical system. This might be the circuit breaker, fuse box or system switch. A certified technician can inspect electrical connections and wiring until they uncover 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 conduct a factory reset of your thermostat to ensure it’s not merely a software issue. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start inspecting connectors.

They’ll shut off the power and slowly check each wire, making sure they are fully inserted into the connector with the correct amount of exposed copper. After they find the damaged connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can show up 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 drains and the thermostat will subsequently shut down. In the event the breakers are on, you can inspect a handful of other places before calling a professional technician.

Since this error can drain your thermostat’s battery, the first step may be providing enough power to figure out if this specific error code is what you’re working with. You can disconnect the thermostat from its base and deliver power with a USB cable. In the event it presents error code 195, you can continue to visually examine components such as 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's maybe 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 receiving more power than needed. This will sometimes stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. Your technician will meticulously examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it can 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 the absence of one can block your Nest from getting enough power. You can examine the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you can get a Nest Power Connector.

With installation of a Nest Power Connector, you will sometimes 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 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 stemming from an overcurrent. If excess power is being delivered using the Nest’s wiring, it may damage internal components and may even be a fire hazard. If you see this error code pop 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 you can. You can then get in touch with a professional technician with the appropriate experience identifying and fixing electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power. This could be as simple as the breaker being switched off, but it may also be something with the wiring. After switching 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 seems to be out of place, it’s time to contact a local professional.