How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using 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 can expect, it won’t work properly or at all if you see an error code appear. The precise error code provides useful information about the underlying problem, something a trained technician can use to offer solutions that much faster.

Let's consider seven of the most frequent error codes you might find on your Nest thermostat. We’ll explain the basics of each error code as well as how you could address it and the estimated cost to do so. Remember that while the costs will ultimately be dependent on the specific Nest model, you can expect to pay between $75-$200 for repairs. This should also cover travel and labor costs on top of any specific components required to wrap up repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and appears when the power is detached 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 the screen until the issue is dealt with.

Losing power to your Nest thermostat can be for a number of reasons. The wiring may have disconnected or become damaged, or a disconnection may have appeared further along in your electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician can inspect electrical connections and wiring until they locate the root of the problem.

e294 - Critical

Critical error code e294 shows up 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 ensure it’s not just a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and start inspecting connectors.

They’ll disconnect the power and slowly inspect each wire, seeing to it that they are fully placed into the connector with the proper amount of bare copper. When they find the damaged connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can show up when the weather outside is severely hot. The HVAC system can fail and stop delivering power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will subsequently shut down. In the event the breakers are on, you can inspect a few other places before contacting a professional technician.

As this error can consume your thermostat’s battery, the first step could be providing enough power to figure out if this specific error code is what you’re working with. You can disconnect the thermostat from its base and deliver power through a USB cable. If it displays 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 detect anything wrong with these components, it will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical problem with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is experiencing more power than necessary. This may stem from the breaker box, an error from the control board or because of a bad connection in the thermostat. The technician needs to meticulously 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 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 receiving adequate 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.

Due to installation of a Nest Power Connector, you might notice error code E297 show up. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already 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 stemming from an overcurrent. If excessive power is sent through the Nest’s wiring, it can damage internal components and can even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to protect from electrical damage, it’s recommended to switch the power off as soon as you can. You can then contact a professional technician with the proper experience identifying and solving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it indicates 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 inspect the wires to make sure nothing is loose or damaged. If nothing seems to be out of place, it’s best to speak with a local professional.