How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the best ways to improve the daily schedule of your heating and cooling. This smart thermostat can recognize your preferences and automatically make adjustments. But as you may expect, it won’t work well or at all if you see an error code appear. The precise error code offers useful information about the underlying problem, something a trained technician can use to provide solutions that much faster.

Let's consider seven of the most common error codes you could discover on your Nest thermostat. We’ll explain the basics of each error code on top of how you can address it and the estimated cost to do so. Keep in mind that while the price will ultimately depend on the precise Nest model, you can expect to pay around $75-$200 for repairs. This should also cover travel and labor costs as well as any specific components necessary to finish repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and shows up when the power is disconnected from the system. As this is a critical power error, the thermostat will swap to the backup battery system. The error message will continue to be displayed until the problem is dealt with.

Losing power to your Nest thermostat can be for a number of reasons. The wiring could have disconnected or become damaged, or a disconnection might have occurred further along in the electrical system. This may be the circuit breaker, fuse box or system switch. A knowledgeable technician can examine 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 complete a factory reset of your thermostat to make sure it’s not simply a software error. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and begin inspecting connectors.

They’ll detach the power and slowly inspect each wire, making sure they are fully placed into the connector with the proper amount of uncovered copper. Once they pinpoint the problem connector, it can be replaced for a new one.

e195 - Critical

This critical error code can surface when the weather outside is particularly hot. The HVAC system can break down and stop delivering power to your Nest thermostat. When this problem persists, the backup battery in your thermostat drains and the thermostat will eventually shut down. Presuming the breakers are on, you can examine a handful of other places before consulting a professional technician.

As this error can drain your thermostat’s battery, the first step may be supplying enough power to determine if this specific error code is what you’re working with. You can disconnect the thermostat from its base and supply power by using a USB cable. If it reveals error code 195, you may 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's maybe best to contact a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical malfunction with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is experiencing more power than what is safe and normal. This may stem from the breaker box, an error from the control board or through a bad connection in the thermostat. Your technician needs to meticulously investigate and test the Nest’s electrical system to understand where the power is surging or why the thermostat is convinced there’s an overcurrent problem.

n260

Although this error code isn’t critical, it can still keep 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 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.

Due to installation of a Nest Power Connector, you will sometimes notice error code E297 show up. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead have 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 using the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to guard against electrical damage, it’s recommended to switch the power off straightaway. You can then get a hold of 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 receiving power. This may be as simple as the breaker being switched off, but it can 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 they’re not loose or damaged. If nothing seems to be out of place, it’s time to contact a local professional.