How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Using a Nest thermostat is one of the most convenient ways to optimize the daily schedule of your heating and cooling. This smart thermostat can recognize 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 appear. The precise error code offers useful information about the root of the problem, something a trained technician can use to provide solutions that much quicker.

Here are seven of the most likely error codes you could discover on your Nest thermostat. We’ll walk you through the basics of each error code as well as how you could fix it and the approximate cost to do so. Remember that while the costs will ultimately hinge on the exact Nest model, you can anticipate paying around $75-$200 for repairs. This should include things like travel and labor costs on top of any specific hardware needed to finish 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. Because this is a critical power error, the thermostat will change to the backup battery system. The error message will continue to be displayed until the issue is fixed.

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

e294 - Critical

Critical error code e294 shows up when your Nest thermostat’s wiring has to be reconfigured. More specifically, you’ll need the technician to 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 check the wiring diagram of the thermostat and begin looking at connectors.

They’ll disconnect the power and progressively check each wire, seeing to it that they are fully placed into the connector with the correct amount of bare copper. Once they locate the malfunctioning connector, it can be swapped for a new one.

e195 - Critical

This critical error code can appear when the weather outside is especially hot. The HVAC system can break down and stop sending power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will eventually power down. Assuming the breakers are on, you can search a couple of other places before calling a professional technician.

As this error can consume your thermostat’s battery, the first step could be supplying enough power to find out if this specific error code is what you’re facing. You can disconnect the thermostat from its base and deliver power by using a USB cable. If it presents error code 195, you can continue to visually examine components such as 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's maybe best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 suggests an electrical error with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is getting more power than necessary. This will sometimes stem from the breaker box, an error from the control board or because of a bad connection in the thermostat. A technician can meticulously investigate and test the Nest’s electrical system to figure out where the power is surging or why the thermostat is convinced there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it may still stop you from using the Nest thermostat like normal. Error code n260 pertains to the lack of a C wire or Nest Power Connector, as not having one can block your Nest from receiving enough power. You can inspect the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you need a Nest Power Connector.

During installation of a Nest Power Connector, you may notice error code E297 show up. 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

Similar to error code e103, e104 is a critical error stemming from an overcurrent. If excessive power is sent using the Nest’s wiring, it could damage internal components and may even be a fire hazard. If you notice this error code show up on your Nest thermostat and want to guard against electrical damage, it’s suggested to shut the power off straightaway. You can then get a hold of a professional technician with the proper experience detecting and resolving electrical damage.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not getting power. This may be as simple as the breaker being turned off, but it could also be a problem with the wiring. After shutting 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 time to contact a local professional.