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 everyday schedule of your comfort system. This smart thermostat can be taught your preferences and automatically make improvements. But as you might 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 source of the problem, something a knowledgeable technician can use to offer solutions that much quicker.

Let's consider seven of the most likely error codes you may encounter on your Nest thermostat. We’ll explain the basics of each error code along with how you can address it and the estimated cost to do so. Remember that while the price will ultimately be dependent on the precise Nest model, you can expect to pay about $75-$200 for repairs. This should also cover travel and labor costs on top of any specific components required to complete 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 swap 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 a number of reasons. The wiring may have disconnected or become damaged, or a disconnection could have happened further along in your electrical system. This might be the circuit breaker, fuse box or system switch. A certified technician should inspect 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 has to be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to ensure it’s not simply a software error. If that doesn’t work, they’ll review the wiring diagram of the thermostat and begin inspecting connectors.

They’ll shut off the power and slowly check each wire, ensuring they are fully inserted into the connector with the correct amount of exposed 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 shut down and stop sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will finally turn off. Assuming the breakers are on, you can check a few other places before contacting a professional technician.

Since this error can drain your thermostat’s battery, the first step may be providing enough power to figure out if this specific error code is what you’re facing. You can disconnect the thermostat from its base and deliver power with a USB cable. If it displays error code 195, you should 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 will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical malfunction with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is getting more power than what is safe and normal. This will sometimes stem from the breaker box, an error from the control board or thanks to a bad connection in the thermostat. The technician should cautiously inspect and test the Nest’s electrical system to understand 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 could still prevent you from using the Nest thermostat how you want to. Error code n260 concerns the lack of a C wire or Nest Power Connector, as not having one can block your Nest from getting sufficient power. You can examine the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you can get a Nest Power Connector.

During 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 is already installed, you’ll instead have 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 that's the result of an overcurrent. If excessive power is transported through the Nest’s wiring, it may damage internal components and may even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to guard against electrical damage, it’s suggested to shut the power off as soon as possible. You can then get in touch with a professional technician with the proper 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 will sometimes be as straightforward as the breaker being switched off, but it can 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 none of them are loose or damaged. If nothing seems to be out of place, it’s time to contact a local professional.