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 comfort system. This smart thermostat can learn your preferences and automatically make improvements. But as you may expect, it won’t work correctly or at all if you see an error code show up. The specific error code supplies useful information about the underlying problem, something a professional technician can use to offer solutions that much faster.

Let's consider seven of the most common error codes you may discover on your Nest thermostat. We’ll review the basics of each error code along with how you can fix it and the projected cost to do so. Keep in mind that while the costs will ultimately hinge on the exact Nest model, you can count on paying around $75-$200 for repairs. This should include travel and labor costs as well as any specific parts needed to finish repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and is displayed when the power is disconnected from the system. As this is a critical power error, the thermostat will change to the backup battery system. The error message will continue to be displayed until the problem is resolved.

Losing power to your Nest thermostat can be for a number of reasons. The wiring could have disconnected or become damaged, or a disconnection might have occurred further along in your home's electrical system. This may be the circuit breaker, fuse box or system switch. A certified technician should examine electrical connections and wiring until they uncover the root of the problem.

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring should 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 make sure it’s not merely a software problem. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start checking connectors.

They’ll detach the power and slowly inspect each wire, ensuring they are fully attached into the connector with the correct amount of exposed copper. When they locate the damaged connector, it can be replaced for a new one.

e195 - Critical

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

As this error can deplete your thermostat’s battery, the first step could be restoring enough power to figure out if this specific error code is what you’re dealing with. You can separate the thermostat from its base and supply power by using a USB cable. Assuming it reveals error code 195, you can continue to visually examine components like the wiring as well as your air conditioner’s air filter or drainage system. If you don’t detect anything wrong with these components, it's maybe 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 can refer to an overcurrent problem, which means the wiring is experiencing more power than necessary. This may stem from the breaker box, an error from the control board or through a bad connection in the thermostat. The technician needs to carefully inspect and test the Nest’s electrical system to figure out where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it may 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 missing one can block your Nest from obtaining adequate power. You can inspect the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you’ll need a Nest Power Connector.

Due to 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 has already been installed, you’ll instead be required to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.

e104 - Critical

Like error code e103, e104 is a critical error stemming from an overcurrent. If too much power is sent using the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you notice this error code show up on your Nest thermostat and want to protect from electrical damage, it’s recommended to switch the power off as soon as possible. You can then get in touch with a professional technician with the proper experience diagnosing and solving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This may be as simple as the breaker being turned off, but it could 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 nothing is loose or damaged. If nothing appears to be out of place, it’s best to get in touch with a local professional.