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 day-to-day schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make changes. But as you can expect, it won’t work properly or at all if you see an error code on the display. The precise error code supplies useful information about the source of the problem, something a professional technician can use to offer solutions that much quicker.

Listed below are seven of the most frequent error codes you may find on your Nest thermostat. We’ll explain the basics of each error code along with how you could address it and the estimated cost to do so. Keep in mind that while the costs will ultimately hinge on the precise Nest model, you can count on paying about $75-$200 for repairs. This should include things like travel and labor costs as well as any specific parts needed to wrap up repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and is displayed when the power is shut off. Since 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 resolved.

Losing power to your Nest thermostat can be for numerous reasons. The wiring could have disconnected or become damaged, or a disconnection may have happened further along in your home's electrical system. This could be the circuit breaker, fuse box or system switch. A certified technician will check electrical connections and wiring until they locate the source of the problem.

e294 - Critical

Critical error code e294 is displayed when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to make sure it’s not just a software problem. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start inspecting connectors.

They’ll detach the power and slowly check each wire, seeing to it that they are fully attached into the connector with the proper amount of bare copper. After they pinpoint the malfunctioning connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can show up when the weather outside is especially 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 depletes and the thermostat will finally power down. Assuming the breakers are on, you can check a couple of other places before consulting a professional technician.

As this error can deplete your thermostat’s battery, the first step may be restoring enough power to figure out if this specific error code is what you’re dealing with. You can detach the thermostat from its base and supply power through a USB cable. If 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's maybe best to contact a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical error with your Nest thermostat. More specifically, e103 may 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 defective 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 is convinced there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it can still stop you from using the Nest thermostat how you prefer to. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from getting enough 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’ll need a Nest Power Connector.

Due to installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead need 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 being delivered through the Nest’s wiring, it may damage internal components and may even be a fire hazard. If you notice this error code show up on your Nest thermostat and want to guard against electrical damage, it’s recommended to switch the power off straightaway. You can then contact a professional technician with the proper experience detecting and resolving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power. This will sometimes be as simple as the breaker being turned off, but it may 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 they’re not loose or damaged. If nothing looks to be out of place, it’s a good idea to speak with a local professional.