Operating a Nest thermostat is one of the easiest ways to optimize the day-to-day schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make improvements. But as you might expect, it won’t work well or at all if you see an error code appear. The precise error code provides useful information about the root of the problem, something a trained technician can use to present solutions that much quicker.

Listed below are seven of the most likely error codes you might discover on your Nest thermostat. We’ll explain the basics of each error code on top of how you might solve it and the projected cost to do so. Keep in mind that while the price will ultimately hinge on the exact Nest model, you can count on paying around $75-$200 for repairs. This should also cover travel and labor costs as well as any specific parts 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. Because this is a critical power error, the thermostat will switch 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 might have disconnected or become damaged, or a disconnection may have happened further along in your electrical system. This could be the circuit breaker, fuse box or system switch. A certified technician can check electrical connections and wiring until they uncover the root of the problem.

e294 – Critical

Critical error code e294 shows up when your Nest thermostat’s wiring needs to be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to ensure it’s not just a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start inspecting connectors.

They’ll disconnect the power and gradually look at each wire, seeing to it that they are fully placed into the connector with the correct amount of uncovered copper. When they find the malfunctioning connector, it can be replaced for a new one.

e195 – Critical

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

Because this error can consume your thermostat’s battery, the first step could be supplying enough power to determine if this specific error code is what you’re dealing with. You can detach the thermostat from its base and deliver power with a USB cable. In the event it displays error code 195, you should continue to visually inspect 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 will likely be best to get in touch with a pro.

e103 – Critical

Another critical error code, e103 indicates an electrical error with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is receiving more power than needed. This may stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. The technician needs to carefully investigate and test the Nest’s electrical system to understand where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

Although this error code isn’t critical, it could still prevent you from using the Nest thermostat like normal. Error code n260 concerns the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining sufficient power. You can check 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.

With installation of a Nest Power Connector, you may notice error code E297 appear. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already 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 originating from an overcurrent. If excessive power is being delivered using the Nest’s wiring, it may damage internal components and can even be a fire hazard. If you see this error code appear on your Nest thermostat and want to take steps to prevent electrical damage, it’s a good idea to turn the power off straightaway. You can then get in touch with a professional technician with the necessary experience diagnosing and solving electrical problems.

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 switched off, but it could also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually check the wires to make sure nothing is loose or damaged. If nothing appears to be out of place, it’s a good idea to get in touch with a local professional.