How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the easiest ways to improve the daily schedule of your HVAC system. This smart thermostat can recognize your preferences and automatically make adjustments. But as you can expect, it won’t work well or at all if you see an error code on the display. The precise error code offers useful information about the root of the problem, something a trained technician can use to offer solutions that much quicker.

Listed below are seven of the most common error codes you might encounter 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. Don't forget that while the price will ultimately depend on the precise Nest model, you can expect to pay about $75-$200 for repairs. This should include travel and labor costs along with any specific hardware needed 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 disconnected from the system. As 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 fixed.

Losing power to your Nest thermostat can be for numerous reasons. The wiring may have disconnected or become damaged, or a disconnection might have happened further along in the electrical system. This might be the circuit breaker, fuse box or system switch. A trained technician should inspect 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 will need to reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to make sure it’s not just a software problem. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start checking connectors.

They’ll shut off the power and gradually inspect each wire, seeing to it that they are fully placed into the connector with the correct amount of bare copper. When they locate the malfunctioning connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can appear when the weather outside is particularly hot. The HVAC system can fail and stop delivering power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will subsequently shut down. Presuming the breakers are on, you can examine a few other places before contacting a professional technician.

Since this error can drain your thermostat’s battery, the first step might be restoring enough power to find out if this specific error code is what you’re facing. You can separate the thermostat from its base and deliver power through a USB cable. If it displays error code 195, you can continue to visually check components like the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to detect anything wrong with these components, it's maybe best to contact a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical malfunction with your Nest thermostat. More specifically, e103 may 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 because of a faulty connection in the thermostat. A technician will meticulously investigate 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

Although this error code isn’t critical, it might still keep you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as the absence of 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 adjust the wiring itself if there is. If not, you need a Nest Power Connector.

Due to installation of a Nest Power Connector, you may 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 be required to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.

e104 - Critical

Just like error code e103, e104 is a critical error stemming from an overcurrent. If excessive 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 pop up on your Nest thermostat and want to protect from electrical damage, it’s recommended to switch the power off straightaway. You can then contact a professional technician with the proper experience detecting and resolving electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not getting power. This might be as simple as the breaker being turned off, but it may also be something with the wiring. After turning off the power to your HVAC system and thermostat, you can visually examine the wires to make sure they’re not loose or damaged. If nothing seems to be out of place, it’s a good idea to get in touch with a local professional.