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 perfect the day-to-day schedule of your HVAC system. This smart thermostat can recognize your preferences and automatically make changes. But as you can 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 source of the problem, something a professional technician can use to present solutions that much quicker.

Listed below are seven of the most frequent error codes you may encounter on your Nest thermostat. We’ll walk you through the basics of each error code along with how you can solve it and the projected cost to do so. Remember that while the costs will ultimately be dependent on the exact Nest model, you can expect to pay between $75-$200 for repairs. This should include travel and labor costs on top of any specific parts necessary to wrap up repairs.

e298 - Critical

This critical error code is limited to the latest models of the Nest thermostat and is displayed when the power is detached from the system. As this is a critical power error, the thermostat will change to the backup battery system. The error message will remain on display until the issue is fixed.

Losing power to your Nest thermostat can be for several reasons. The wiring might 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 certified technician can check 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 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 error. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start inspecting connectors.

They’ll shut off the power and gradually check each wire, ensuring they are fully attached into the connector with the correct amount of uncovered copper. When they find the problem connector, it can be swapped for a new one.

e195 - Critical

This critical error code can appear when the weather outside is severely hot. The HVAC system can shut down and stop delivering power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will finally turn off. Presuming the breakers are on, you can examine a couple of other places before contacting a professional technician.

Because this error can deplete your thermostat’s battery, the first step might be supplying 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 by using a USB cable. Assuming it reveals error code 195, you can continue to visually inspect components like 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 get in touch with a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical error with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is receiving more power than needed. This can stem from the breaker box, an error from the control board or because of a defective connection in the thermostat. The technician will carefully examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

Although this error code isn’t critical, it might still prevent you from using the Nest thermostat like normal. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from getting 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’ll need a Nest Power Connector.

Due to installation of a Nest Power Connector, you will sometimes 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

Like error code e103, e104 is a critical error originating from an overcurrent. If excessive power is being delivered using the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you see this error code appear on your Nest thermostat and want to guard against electrical damage, it’s suggested to switch the power off straightaway. You can then get in touch with a professional technician with the appropriate experience identifying and fixing electrical malfunctions.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This could be as easy as the breaker being turned off, but it may also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually check the wires to make sure nothing is loose or damaged. If nothing looks to be out of place, it’s a good idea to get in touch with a local professional.