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 everyday schedule of your comfort system. This smart thermostat can learn your preferences and automatically make improvements. But as you may expect, it won’t work well or at all if you see an error code show up. The exact error code supplies useful information about the root of the problem, something a trained technician can use to offer solutions that much faster.

Let's consider seven of the most frequent error codes you may discover on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you could fix it and the approximate cost to do so. Keep in mind that while the costs will ultimately hinge on the exact Nest model, you can anticipate paying between $75-$200 for repairs. This should also cover travel and labor costs on top of any specific components needed to finish repairs.

e298 - Critical

This critical error code is limited to new 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 switch to the backup battery system. The error message will remain on display until the problem is resolved.

Losing power to your Nest thermostat can be for numerous reasons. The wiring might have disconnected or become damaged, or a disconnection could have occurred further along in the electrical system. This could be the circuit breaker, fuse box or system switch. A professional technician should examine electrical connections and wiring until they locate the source of the problem.

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to make sure 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 detach the power and progressively inspect each wire, seeing to it that they are fully placed into the connector with the correct amount of uncovered copper. Once they locate the malfunctioning connector, it can be replaced for a new one.

e195 - Critical

This critical error code can appear when the weather outside is especially hot. The HVAC system can fail and stop giving power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will subsequently turn off. Assuming the breakers are on, you can examine a few other places before contacting a professional technician.

Because this error can drain your thermostat’s battery, the first step might be restoring enough power to find out if this specific error code is what you’re facing. You can detach the thermostat from its base and provide power through a USB cable. If it displays 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 find anything wrong with these components, it's maybe best to contact a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical malfunction with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is receiving more power than what is safe and normal. This can stem from the breaker box, an error from the control board or through a bad connection in the thermostat. Your technician can carefully examine and test the Nest’s electrical system to determine where the power is surging or why the thermostat is convinced there’s an overcurrent problem.

n260

While this error code isn’t critical, it can still keep you from using the Nest thermostat like normal. Error code n260 refers to the lack of a C wire or Nest Power Connector, as not having 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 adjust the wiring itself if there is. If not, you’ll need a Nest Power Connector.

With installation of a Nest Power Connector, you might notice error code E297 be displayed. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead need to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.

e104 - Critical

Just like error code e103, e104 is a critical error originating from an overcurrent. If too much power is sent inside the Nest’s wiring, it may damage internal components and could even be a fire hazard. If you notice this error code show up on your Nest thermostat and want to protect from electrical damage, it’s a good idea to shut the power off straightaway. You can then get in touch with a professional technician with the necessary experience detecting and resolving 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 straightforward as the breaker being turned off, but it may also be a problem with the wiring. After shutting 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 looks to be out of place, it’s best to get in touch with a local professional.