How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the easiest ways to perfect the day-to-day schedule of your comfort system. This smart thermostat can learn your preferences and automatically make changes. But as you can expect, it won’t work correctly or at all if you see an error code appear. The specific error code supplies useful information about the source of the problem, something a trained technician can use to present solutions that much sooner.

Here are seven of the most frequent error codes you may encounter on your Nest thermostat. We’ll review the basics of each error code along with how you could solve it and the estimated cost to do so. Remember that while the costs will ultimately be dependent on the exact Nest model, you can count on paying between $75-$200 for repairs. This should include travel and labor costs on top of 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 detached from the system. Since this is a critical power error, the thermostat will switch to the backup battery system. The error message will remain on display until the issue is dealt with.

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 the electrical system. This could be the circuit breaker, fuse box or system switch. A professional technician will examine electrical connections and wiring until they find the source of the problem.

e294 - Critical

Critical error code e294 is displayed when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not simply 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 slowly check each wire, seeing to it that they are fully placed into the connector with the proper amount of bare copper. When they pinpoint the problem 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 fail and stop delivering power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will eventually turn off. In the event the breakers are on, you can inspect a couple of other places before consulting a professional technician.

As this error can drain your thermostat’s battery, the first step could be supplying 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 with a USB cable. Assuming it presents error code 195, you may continue to visually inspect components like 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 get in touch with a pro.

e103 - Critical

Another critical error code, e103 indicates 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 can stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. The technician can 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

Even though this error code isn’t critical, it may still prevent you from using the Nest thermostat how you want to. Error code n260 refers to the lack of a C wire or Nest Power Connector, as not having 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’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 resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead need 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 that's the result of an overcurrent. If too much power is being delivered using the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to protect from electrical damage, it’s a good idea to switch the power off straightaway. You can then get in touch with a professional technician with the necessary experience identifying and solving electrical damage.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power. This might be as straightforward as the breaker being turned off, but it can also be an issue with the wiring. After turning 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 looks to be out of place, it’s a good idea to get in touch with a local professional.