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 improve the daily schedule of your HVAC system. This smart thermostat can be taught your preferences and automatically make changes. But as you might expect, it won’t work properly or at all if you see an error code appear. The specific error code provides useful information about the root of the problem, something a professional technician can use to offer solutions that much sooner.

Listed below are seven of the most common error codes you might find on your Nest thermostat. We’ll explain the basics of each error code along with how you might fix it and the approximate cost to do so. Keep in mind that while the price will ultimately hinge on the precise Nest model, you can expect to pay between $75-$200 for repairs. This should also cover travel and labor costs as well as any specific components necessary to wrap up 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. Since 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 fixed.

Losing power to your Nest thermostat can be for numerous reasons. The wiring may 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 knowledgeable technician can check electrical connections and wiring until they find the source of the problem.

e294 - Critical

Critical error code e294 is displayed when your Nest thermostat’s wiring has to be reconfigured. More specifically, the technician will need to reconfigure the R wire. They’ll first perform a factory reset of your thermostat to ensure it’s not simply a software issue. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin checking connectors.

They’ll shut off the power and slowly look at each wire, making sure they are fully attached into the connector with the proper amount of uncovered copper. When they find the problem connector, it can be replaced for a new one.

e195 - Critical

This critical error code can surface when the weather outside is severely hot. The HVAC system can break down and stop giving power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat depletes and the thermostat will finally turn off. Assuming the breakers are on, you can check a couple of other places before consulting a professional technician.

Because this error can deplete your thermostat’s battery, the first step might be providing enough power to find out if this specific error code is what you’re working with. You can separate the thermostat from its base and provide power through a USB cable. Assuming it presents error code 195, you may 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 find anything wrong with these components, it will probably be best to contact a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical malfunction with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is experiencing 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. Your technician needs to carefully inspect 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

While this error code isn’t critical, it could still prevent you from using the Nest thermostat how you want to. Error code n260 concerns the lack of a C wire or Nest Power Connector, as the absence of one can block your Nest from receiving adequate 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.

Due to installation of a Nest Power Connector, you will sometimes notice error code E297 appear. This can be dealt with 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

Like error code e103, e104 is a critical error that's the result of an overcurrent. If too much power is being delivered using the Nest’s wiring, it may damage internal components and may even be a fire hazard. If you see this error code pop up on your Nest thermostat and want to protect from electrical damage, it’s recommended to turn the power off as soon as you can. You can then contact a professional technician with the necessary experience detecting and resolving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This may be as easy as the breaker being switched 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 none of them are loose or damaged. If nothing appears to be out of place, it’s time to get in touch with a local professional.