How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the most convenient ways to optimize the everyday schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make improvements. But as you might expect, it won’t work correctly or at all if you see an error code appear. The exact error code provides useful information about the root of the problem, something a knowledgeable technician can use to provide solutions that much faster.

Let's consider seven of the most frequent error codes you could discover on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you can solve it and the estimated cost to do so. Remember that while the price will ultimately depend on the specific 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 hardware needed to complete repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and shows up when the power is disconnected 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 dealt with.

Losing power to your Nest thermostat can be for several reasons. The wiring might have disconnected or become damaged, or a disconnection might have occurred further along in your electrical system. This could be the circuit breaker, fuse box or system switch. A knowledgeable technician can examine electrical connections and wiring until they find the source of the problem.

e294 - Critical

Critical error code e294 is displayed when your Nest thermostat’s wiring has 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 problem. If that doesn’t work, they’ll review the wiring diagram of the thermostat and begin looking at connectors.

They’ll shut off the power and progressively check each wire, ensuring they are fully placed into the connector with the proper 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 appear when the weather outside is severely hot. The HVAC system can shut down and stop delivering power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will finally turn off. Presuming the breakers are on, you can check a couple of other places before calling a professional technician.

Since 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 disconnect the thermostat from its base and deliver power through a USB cable. If it presents error code 195, you should continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to uncover anything wrong with these components, it's maybe best to call a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical issue with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is experiencing more power than needed. This will sometimes stem from the breaker box, an error from the control board or through a defective connection in the thermostat. Your technician can cautiously inspect 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 prevent you from using the Nest thermostat how you prefer to. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from getting enough 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 need a Nest Power Connector.

With installation of a Nest Power Connector, you may notice error code E297 show up. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead be required 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 stemming from an overcurrent. If excess power is being delivered 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 a good idea to turn the power off as soon as possible. You can then get in touch with a professional technician with the necessary experience identifying and solving electrical damage.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This may be as easy as the breaker being switched off, but it could also be a problem with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually check the wires to make sure none of them are loose or damaged. If nothing appears to be out of place, it’s best to contact a local professional.