How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the best ways to optimize the everyday schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make changes. But as you may expect, it won’t work well or at all if you see an error code show up. The precise error code provides useful information about the source of the problem, something a professional technician can use to present solutions that much sooner.

Listed below are seven of the most likely error codes you could find on your Nest thermostat. We’ll review the basics of each error code on top of how you can solve it and the estimated cost to do so. Don't forget that while the price will ultimately hinge on the exact Nest model, you can expect to pay about $75-$200 for repairs. This should include things like travel and labor costs as well as any specific hardware needed to complete repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and shows up 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 numerous reasons. The wiring could have disconnected or become damaged, or a disconnection could have appeared further along in your home's electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician can examine 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 should be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to ensure it’s not merely a software error. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start checking connectors.

They’ll shut off the power and gradually look at each wire, making sure they are fully attached into the connector with the correct amount of exposed copper. Once they pinpoint the damaged connector, it can be replaced for a new one.

e195 - Critical

This critical error code can appear when the weather outside is especially hot. The HVAC system can shut down and stop sending power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will eventually turn off. Assuming the breakers are on, you can examine a handful of other places before calling a professional technician.

Because this error can consume your thermostat’s battery, the first step may be supplying enough power to find out if this specific error code is what you’re facing. You can detach the thermostat from its base and deliver power by using a USB cable. Assuming it reveals error code 195, you can continue to visually inspect components including the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to uncover anything wrong with these components, it will likely be best to call a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical error with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is getting more power than necessary. This will sometimes stem from the breaker box, an error from the control board or through a faulty connection in the thermostat. Your technician needs to cautiously examine and test the Nest’s electrical system to figure out where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Although this error code isn’t critical, it may 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 the absence of 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 adjust the wiring itself if there is. If not, you need a Nest Power Connector.

With installation of a Nest Power Connector, you may notice error code E297 show up. This can be remedied 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

Like error code e103, e104 is a critical error that's the result of an overcurrent. If excess power is being delivered using the Nest’s wiring, it can damage internal components and could even be a fire hazard. If you see this error code show up on your Nest thermostat and want to guard against electrical damage, it’s recommended to shut the power off straightaway. You can then contact a professional technician with the necessary experience identifying and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This might be as simple as the breaker being switched off, but it could also be a problem 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 seems to be out of place, it’s best to contact a local professional.