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 optimize the daily schedule of your HVAC system. This smart thermostat can recognize your preferences and automatically make improvements. But as you may expect, it won’t work correctly or at all if you see an error code on the display. The precise error code supplies useful information about the root of the problem, something a professional technician can use to present solutions that much sooner.

Listed below are seven of the most common error codes you might encounter on your Nest thermostat. We’ll review the basics of each error code along with how you can solve it and the projected cost to do so. Remember 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 on top of any specific parts necessary to finish 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. Since 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 resolved.

Losing power to your Nest thermostat can be for a number of reasons. The wiring could have disconnected or become damaged, or a disconnection might have happened further along in your electrical system. This might be the circuit breaker, fuse box or system switch. A professional technician can check electrical connections and wiring until they uncover the source 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 complete a factory reset of your thermostat to make sure it’s not simply a software problem. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start inspecting connectors.

They’ll shut off the power and gradually inspect each wire, seeing to it that they are fully inserted into the connector with the proper amount of exposed copper. Once they pinpoint the malfunctioning connector, it can be swapped for a new one.

e195 - Critical

This critical error code can show up when the weather outside is especially hot. The HVAC system can break down and stop giving power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat depletes and the thermostat will finally turn off. In the event the breakers are on, you can inspect a couple of other places before contacting a professional technician.

Because this error can deplete your thermostat’s battery, the first step might be providing enough power to find out if this specific error code is what you’re working with. You can separate the thermostat from its base and supply power with a USB cable. In the event it reveals 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 struggle to find anything wrong with these components, it will probably be best to get in touch with 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 what is safe and normal. This may stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. A technician needs to meticulously 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

Although this error code isn’t critical, it can still keep you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining enough power. You can examine the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you’ll need a Nest Power Connector.

With installation of a Nest Power Connector, you might 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 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 that's the result of an overcurrent. If excess power is sent using the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to protect from electrical damage, it’s recommended to switch the power off straightaway. You can then get a hold of a professional technician with the proper experience detecting and resolving electrical damage.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not receiving power. This may be as straightforward as the breaker being shut off, but it can also be a problem with the wiring. After switching 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 time to speak with a local professional.