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 day-to-day schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make improvements. But as you may expect, it won’t work properly or at all if you see an error code on the display. The specific error code provides useful information about the source of the problem, something a professional technician can use to offer solutions that much quicker.

Let's consider seven of the most frequent error codes you might discover on your Nest thermostat. We’ll review the basics of each error code along with how you could solve it and the approximate cost to do so. Remember that while the costs will ultimately depend on the exact Nest model, you can expect to pay around $75-$200 for repairs. This should also cover travel and labor costs along with any specific components necessary to finish repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and shows up when the power is shut off. As this is a critical power error, the thermostat will swap 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 occurred further along in the electrical system. This could be the circuit breaker, fuse box or system switch. A professional technician will inspect electrical connections and wiring until they find 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 should reconfigure the R wire. They’ll first complete a factory reset of your thermostat to make sure it’s not just a software issue. 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 gradually look at each wire, making sure they are fully inserted into the connector with the proper amount of bare copper. When 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 severely hot. The HVAC system can shut down and stop delivering power to your Nest thermostat. When this problem persists, the backup battery in your thermostat depletes and the thermostat will eventually turn off. Presuming the breakers are on, you can check a few other places before calling a professional technician.

As this error can consume your thermostat’s battery, the first step might be restoring enough power to determine if this specific error code is what you’re dealing with. You can detach the thermostat from its base and provide power by using a USB cable. In the event it presents error code 195, you should continue to visually examine components such as the wiring as well as your air conditioner’s air filter or drainage system. If you can't uncover anything wrong with these components, it will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical issue with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is receiving more power than what is safe and normal. This will sometimes stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. The technician should carefully inspect 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

Even though this error code isn’t critical, it can still prevent 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 not having one can block your Nest from receiving enough 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 can get a Nest Power Connector.

With installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector has already been 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 that's the result of an overcurrent. If too much power is transported through 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 guard against electrical damage, it’s recommended to shut the power off as soon as you can. You can then get in touch with a professional technician with the appropriate experience diagnosing and resolving electrical damage.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This could be as easy as the breaker being switched off, but it can also be an issue with the wiring. After shutting off the power to your HVAC system and thermostat, you can visually examine the wires to make sure they’re not loose or damaged. If nothing seems to be out of place, it’s best to contact a local professional.