How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the best ways to perfect the day-to-day schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make improvements. But as you might expect, it won’t work properly or at all if you see an error code show up. The exact error code provides useful information about the root of the problem, something a professional technician can use to present solutions that much quicker.

Here are seven of the most common error codes you may find on your Nest thermostat. We’ll explain the basics of each error code on top of how you might address it and the approximate cost to do so. Keep in mind that while the costs will ultimately be dependent on the precise Nest model, you can count on paying about $75-$200 for repairs. This should include things like travel and labor costs along with any specific parts necessary to finish repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and appears when the power is disconnected from the system. Since this is a critical power error, the thermostat will switch to the backup battery system. The error message will remain on display until the problem is dealt with.

Losing power to your Nest thermostat can be for several reasons. The wiring could have disconnected or become damaged, or a disconnection might have appeared further along in your home's electrical system. This may be the circuit breaker, fuse box or system switch. A trained technician will examine electrical connections and wiring until they find 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 should 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 check the wiring diagram of the thermostat and begin inspecting connectors.

They’ll shut off the power and gradually inspect each wire, making sure they are fully inserted into the connector with the proper amount of exposed copper. When they pinpoint the malfunctioning connector, it can be replaced for a new one.

e195 - Critical

This critical error code can show up when the weather outside is especially hot. The HVAC system can fail and stop giving power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will eventually shut down. Presuming the breakers are on, you can search a couple of other places before calling a professional technician.

Because this error can deplete your thermostat’s battery, the first step could be supplying 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 provide power by using a USB cable. In the event it displays error code 195, you can continue to visually check components such as 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 contact a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical error with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is receiving more power than needed. This may stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. Your technician should 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

While this error code isn’t critical, it might still prevent you from using the Nest thermostat how you want to. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as the absence of one can block your Nest from receiving 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 can get a Nest Power Connector.

With installation of a Nest Power Connector, you might notice error code E297 show up. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already 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 too much power is being delivered using the Nest’s wiring, it could damage internal components and could even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to take steps to prevent electrical damage, it’s a good idea to shut the power off as soon as possible. You can then get a hold of a professional technician with the appropriate experience diagnosing and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This could be as easy as the breaker being switched off, but it may also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually examine the wires to make sure they’re not loose or damaged. If nothing appears to be out of place, it’s best to contact a local professional.