How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the easiest ways to perfect the everyday schedule of your HVAC system. This smart thermostat can learn your preferences and automatically make adjustments. But as you might expect, it won’t work properly or at all if you see an error code on the display. The specific error code provides useful information about the root of the problem, something a professional technician can use to present solutions that much quicker.

Listed below are seven of the most common error codes you could encounter on your Nest thermostat. We’ll explain the basics of each error code as well as how you can fix it and the estimated cost to do so. Remember that while the price will ultimately depend on the precise Nest model, you can count on paying around $75-$200 for repairs. This should include travel and labor costs on top of any specific components necessary to complete repairs.

e298 - Critical

This critical error code is limited to the latest 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 switch 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 several reasons. The wiring might have disconnected or become damaged, or a disconnection could have appeared further along in your electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician can inspect electrical connections and wiring until they find the root of the problem.

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring has 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 just a software issue. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start inspecting connectors.

They’ll detach the power and slowly check each wire, seeing to it that they are fully attached into the connector with the proper amount of exposed copper. After they pinpoint the damaged connector, it can be exchanged for a new one.

e195 - Critical

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

Since this error can deplete your thermostat’s battery, the first step may be restoring enough power to figure out if this specific error code is what you’re facing. You can detach the thermostat from its base and deliver power by using a USB cable. In the event it presents error code 195, you can continue to visually examine components including 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 probably be best to contact a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical malfunction with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is getting more power than necessary. This can stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. The technician will meticulously inspect and test the Nest’s electrical system to understand where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Although this error code isn’t critical, it can 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 adequate power. You can examine the Nest’s C connector for the presence of a C wire and adjust the wiring itself if there is. If not, you can get a Nest Power Connector.

During installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector was 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 sent through the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to protect from electrical damage, it’s a good idea to switch the power off as soon as possible. You can then get in touch with a professional technician with the necessary experience diagnosing and fixing electrical problems.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This might be as straightforward as the breaker being shut off, but it may also be a problem with the wiring. After switching 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 looks to be out of place, it’s time to contact a local professional.