How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the best ways to optimize the everyday schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make changes. 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 supplies useful information about the underlying problem, something a professional technician can use to offer solutions that much faster.

Here are seven of the most common error codes you might find on your Nest thermostat. We’ll review the basics of each error code as well as how you might address it and the approximate cost to do so. Remember that while the costs will ultimately hinge on the specific Nest model, you can expect to pay around $75-$200 for repairs. This should include travel and labor costs as well as any specific hardware required to wrap up repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and appears when the power is detached from the system. As this is a critical power error, the thermostat will switch to the backup battery system. The error message will remain on display until the problem is dealt with.

Losing power to your Nest thermostat can be for numerous reasons. The wiring may 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 professional technician should check 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 needs 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 merely a software issue. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin looking at connectors.

They’ll disconnect the power and slowly check each wire, making sure they are fully attached into the connector with the correct amount of exposed copper. Once they locate the problem connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can show up when the weather outside is particularly hot. The HVAC system can shut down and stop sending power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will finally shut down. In the event the breakers are on, you can examine a handful of other places before calling a professional technician.

Since this error can deplete your thermostat’s battery, the first step could 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 provide power through a USB cable. If it displays error code 195, you may continue to visually check components including the wiring as well as your air conditioner’s air filter or drainage system. If you don’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 signifies 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 necessary. This will sometimes stem from the breaker box, an error from the control board or through a faulty connection in the thermostat. The technician should meticulously inspect 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 could still stop you from using the Nest thermostat like normal. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining adequate 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 can get a Nest Power Connector.

With installation of a Nest Power Connector, you might 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 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 excess power is transported through the Nest’s wiring, it may damage internal components and could even be a fire hazard. If you see this error code appear on your Nest thermostat and want to protect from electrical damage, it’s recommended to shut the power off straightaway. You can then get in touch with a professional technician with the appropriate experience identifying and fixing electrical problems.

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 shut 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 none of them are loose or damaged. If nothing appears to be out of place, it’s time to contact a local professional.