How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the best ways to optimize the day-to-day schedule of your comfort system. This smart thermostat can be taught your preferences and automatically make adjustments. 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 professional technician can use to present solutions that much quicker.

Here are seven of the most frequent error codes you may find on your Nest thermostat. We’ll review the basics of each error code as well as how you can solve it and the projected cost to do so. Don't forget that while the costs will ultimately depend on the precise Nest model, you can count on paying between $75-$200 for repairs. This should include things like travel and labor costs on top of any specific hardware needed to wrap up repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and is displayed when the power is detached from the system. Because 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 problem is fixed.

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

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring has to be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first perform 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 begin inspecting connectors.

They’ll detach the power and progressively inspect each wire, making sure they are fully placed into the connector with the correct amount of exposed copper. When they locate the malfunctioning connector, it can be swapped for a new one.

e195 - Critical

This critical error code can surface when the weather outside is especially hot. The HVAC system can break down and stop delivering power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will subsequently turn off. Assuming the breakers are on, you can check a few other places before consulting a professional technician.

As this error can consume your thermostat’s battery, the first step might be restoring enough power to find out if this specific error code is what you’re dealing with. You can separate the thermostat from its base and supply power through a USB cable. In the event it presents error code 195, you can continue to visually inspect components including the wiring as well as your air conditioner’s air filter or drainage system. If you can't find anything wrong with these components, it will likely be best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical problem with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is experiencing more power than necessary. This can stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. A technician can meticulously 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 could still keep you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from receiving enough 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 need a Nest Power Connector.

During installation of a Nest Power Connector, you will sometimes notice error code E297 be displayed. 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

Similar to error code e103, e104 is a critical error stemming from an overcurrent. If excessive power is being delivered through the Nest’s wiring, it can damage internal components and could even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to protect from electrical damage, it’s recommended to turn the power off straightaway. You can then get in touch with a professional technician with the proper experience diagnosing and solving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This will sometimes 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 examine the wires to make sure nothing is loose or damaged. If nothing looks to be out of place, it’s time to contact a local professional.