How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the best ways to improve the daily schedule of your comfort system. This smart thermostat can recognize your preferences and automatically make changes. But as you may expect, it won’t work correctly or at all if you see an error code show up. The exact error code offers useful information about the underlying problem, something a professional technician can use to provide solutions that much faster.

Let's consider seven of the most frequent error codes you may encounter on your Nest thermostat. We’ll review the basics of each error code on top of how you could solve it and the projected cost to do so. Keep in mind that while the costs will ultimately hinge on the specific Nest model, you can anticipate paying about $75-$200 for repairs. This should include things like travel and labor costs as well as any specific hardware required to complete repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and shows up when the power is detached from the system. As this is a critical power error, the thermostat will change to the backup battery system. The error message will remain on the screen until the problem is fixed.

Losing power to your Nest thermostat can be for several reasons. The wiring could have disconnected or become damaged, or a disconnection might have happened further along in your home's electrical system. This might be the circuit breaker, fuse box or system switch. A certified 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 should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to make sure it’s not just a software error. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start checking connectors.

They’ll disconnect the power and gradually inspect each wire, making sure they are fully inserted into the connector with the correct amount of uncovered copper. When they locate 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 giving power to your Nest thermostat. When this problem persists, the backup battery in your thermostat drains and the thermostat will eventually turn off. Assuming the breakers are on, you can check a handful of other places before consulting a professional technician.

As this error can drain your thermostat’s battery, the first step could be restoring enough power to determine if this specific error code is what you’re working with. You can detach the thermostat from its base and supply power through a USB cable. Assuming it presents error code 195, you can continue to visually check components including 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 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 receiving more power than necessary. This may stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. Your technician needs to meticulously investigate and test the Nest’s electrical system to determine where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

Although this error code isn’t critical, it can still stop 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 missing one can block your Nest from receiving enough 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.

During installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been 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 sent 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 protect from electrical damage, it’s a good idea to shut the power off as soon as possible. You can then contact a professional technician with the proper experience detecting and resolving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This will sometimes be as straightforward as the breaker being turned off, but it may also be an issue with the wiring. After shutting 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 looks to be out of place, it’s a good idea to contact a local professional.