Operating a Nest thermostat is one of the easiest ways to improve the everyday schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make improvements. But as you may expect, it won’t work properly or at all if you see an error code appear. The exact error code provides useful information about the underlying problem, something a knowledgeable technician can use to provide solutions that much quicker.

Here are seven of the most frequent error codes you could encounter on your Nest thermostat. We’ll review the basics of each error code on top of how you can fix it and the estimated cost to do so. Keep in mind that while the costs will ultimately depend on the precise Nest model, you can count on paying around $75-$200 for repairs. This should also cover travel and labor costs on top of any specific hardware required to complete repairs.

e298 – Critical

This critical error code is limited to newer models of the Nest thermostat and appears when the power is shut off. Because 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 resolved.

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 occurred further along in your electrical system. This may be the circuit breaker, fuse box or system switch. A knowledgeable technician will 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 should be reconfigured. More specifically, the technician will need 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 review the wiring diagram of the thermostat and start looking at connectors.

They’ll shut off the power and progressively check each wire, ensuring they are fully inserted into the connector with the correct amount of uncovered copper. After they find the problem connector, it can be replaced for a new one.

e195 – Critical

This critical error code can show up when the weather outside is severely hot. The HVAC system can fail and stop giving power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat depletes and the thermostat will finally turn off. Presuming the breakers are on, you can check a couple of other places before contacting a professional technician.

Since this error can deplete your thermostat’s battery, the first step could be providing enough power to find out if this specific error code is what you’re dealing with. You can disconnect the thermostat from its base and provide power with a USB cable. In the event 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 can’t find anything wrong with these components, it will probably be best to call a pro.

e103 – Critical

Another critical error code, e103 indicates an electrical error with your Nest thermostat. More specifically, e103 may 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 defective connection in the thermostat. A technician can carefully examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat is convinced there’s an overcurrent problem.

n260

While this error code isn’t critical, it can still prevent you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as not having one can block your Nest from receiving adequate power. You can check the Nest’s C connector for the presence of a C wire and adjust the wiring itself if there is. If not, you need a Nest Power Connector.

Due to installation of a Nest Power Connector, you might notice error code E297 show up. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been 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 stemming from an overcurrent. If excess power is transported through the Nest’s wiring, it can damage internal components and may 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 a good idea to switch the power off as soon as you can. You can then get in touch with a professional technician with the appropriate experience diagnosing and fixing electrical issues.

e73 – Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power.

This could be as straightforward as the breaker being switched off, but it may also be something with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure nothing is loose or damaged. If nothing seems to be out of place, it’s best to get in touch with a local professional.