How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the most convenient ways to perfect the everyday schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make improvements. But as you can expect, it won’t work properly or at all if you see an error code appear. The precise error code provides useful information about the root of the problem, something a professional technician can use to present solutions that much sooner.

Let's consider seven of the most common error codes you might find on your Nest thermostat. We’ll walk you through the basics of each error code as well as how you might address it and the projected cost to do so. Don't forget that while the costs will ultimately depend on the specific Nest model, you can expect to pay around $75-$200 for repairs. This should include travel and labor costs along with any specific components necessary to complete repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and is displayed when the power is detached from the system. As this is a critical power error, the thermostat will swap to the backup battery system. The error message will continue to be displayed until the issue is fixed.

Losing power to your Nest thermostat can be for numerous reasons. The wiring might have disconnected or become damaged, or a disconnection may have appeared further along in your electrical system. This might be the circuit breaker, fuse box or system switch. A knowledgeable technician should examine electrical connections and wiring until they locate the root of the problem.

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring needs to be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first perform 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 checking connectors.

They’ll shut off the power and gradually look at each wire, making sure they are fully inserted into the connector with the proper amount of uncovered copper. After they find the damaged connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can show up when the weather outside is severely hot. The HVAC system can fail and stop delivering power to your Nest thermostat. When this problem persists, the backup battery in your thermostat drains and the thermostat will finally power down. In the event the breakers are on, you can inspect a couple 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 facing. You can detach the thermostat from its base and provide power with a USB cable. If it presents error code 195, you can continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you don’t find anything wrong with these components, it will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical problem with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is experiencing more power than what is safe and normal. This may stem from the breaker box, an error from the control board or through a faulty connection in the thermostat. A technician can carefully investigate 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 can still keep you from using the Nest thermostat like normal. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from receiving 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’ll need a Nest Power Connector.

With installation of a Nest Power Connector, you will sometimes 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 be required 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 originating from an overcurrent. If excessive power is transported inside the Nest’s wiring, it may 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 take steps to prevent electrical damage, it’s recommended to shut the power off as soon as possible. You can then contact a professional technician with the necessary experience diagnosing and solving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This might be as easy as the breaker being turned 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 examine the wires to make sure none of them are loose or damaged. If nothing appears to be out of place, it’s best to speak with a local professional.