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How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Installing a Nest thermostat is one of the most convenient ways to improve the everyday schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make improvements. But as you might expect, it won’t work well or at all if you see an error code on the display. The precise error code provides useful information about the underlying problem, something a knowledgeable technician can use to provide solutions that much quicker.

Let's consider seven of the most likely error codes you may encounter on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you could address it and the projected cost to do so. Keep in mind that while the costs will ultimately be dependent on the specific Nest model, you can count on paying between $75-$200 for repairs. This should include travel and labor costs as well as any specific components needed to finish repairs.

e298 - Critical

This critical error code is limited to newer models of the Nest thermostat and is displayed when the power is disconnected 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 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 might have happened further along in your home's electrical system. This could be the circuit breaker, fuse box or system switch. A certified technician can examine electrical connections and wiring until they uncover the source of the problem.

e294 - Critical

Critical error code e294 appears when your Nest thermostat’s wiring should be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first perform a factory reset of your thermostat to ensure it’s not just a software problem. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and start checking connectors.

They’ll shut off the power and progressively inspect each wire, seeing to it that they are fully placed into the connector with the correct amount of bare copper. When they locate the damaged connector, it can be exchanged 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 giving power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat drains and the thermostat will subsequently power down. Assuming the breakers are on, you can examine a handful of other places before consulting a professional technician.

Since this error can consume your thermostat’s battery, the first step might be supplying enough power to find out if this specific error code is what you’re facing. You can separate the thermostat from its base and supply power by using a USB cable. If it reveals 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 can't 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 signifies an electrical issue 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 thanks to a faulty connection in the thermostat. Your technician needs to meticulously examine and test the Nest’s electrical system to figure out where the power is surging or why the thermostat thinks there’s an overcurrent problem.

n260

Even though this error code isn’t critical, it can 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 adequate power. You can check the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you’ll need a Nest Power Connector.

During installation of a Nest Power Connector, you might notice error code E297 show up. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been 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 stemming from an overcurrent. If excess power is transported inside the Nest’s wiring, it may damage internal components and could even be a fire hazard. If you see this error code show up on your Nest thermostat and want to protect from electrical damage, it’s a good idea to switch the power off as soon as possible. You can then get a hold of a professional technician with the proper experience detecting and solving electrical issues.

e73 - Critical

When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This will sometimes be as easy as the breaker being shut off, but it can also be a problem with the wiring. After turning 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 seems to be out of place, it’s time to get in touch with a local professional.