How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the easiest ways to optimize the everyday schedule of your HVAC system. This smart thermostat can learn 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 on the display. The exact error code supplies useful information about the underlying problem, something a trained technician can use to offer solutions that much quicker.

Listed below are seven of the most common 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 estimated cost to do so. Keep in mind that while the price will ultimately depend on the precise Nest model, you can anticipate paying between $75-$200 for repairs. This should include travel and labor costs on top of any specific components necessary to wrap up repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and shows up when the power is shut off. 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 problem is dealt with.

Losing power to your Nest thermostat can be for a number of reasons. The wiring could 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 can inspect electrical connections and wiring until they uncover 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 make sure it’s not just a software issue. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start checking connectors.

They’ll detach the power and progressively check each wire, making sure they are fully placed into the connector with the correct amount of bare copper. When they locate the damaged connector, it can be swapped for a new one.

e195 - Critical

This critical error code can surface when the weather outside is particularly hot. The HVAC system can fail and stop sending power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will subsequently shut down. Assuming the breakers are on, you can examine a few other places before consulting a professional technician.

Since this error can consume your thermostat’s battery, the first step may be restoring enough power to determine if this specific error code is what you’re working with. You can separate the thermostat from its base and provide power through a USB cable. In the event it displays error code 195, you may continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you can't uncover anything wrong with these components, it will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical issue with your Nest thermostat. More specifically, e103 can 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 because of a faulty connection in the thermostat. Your technician can meticulously investigate and test the Nest’s electrical system to determine where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it may still keep you from using the Nest thermostat how you want to. Error code n260 refers to the lack of a C wire or Nest Power Connector, as not having one can block your Nest from obtaining sufficient 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 can get a Nest Power Connector.

With installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be dealt with 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

Like error code e103, e104 is a critical error originating from an overcurrent. If excessive power is transported using the Nest’s wiring, it could 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 guard against 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 necessary experience diagnosing and resolving electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This may be as easy as the breaker being shut off, but it can also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure none of them are loose or damaged. If nothing seems to be out of place, it’s a good idea to get in touch with a local professional.