Using a Nest thermostat is one of the easiest ways to improve the daily schedule of your heating and cooling. This smart thermostat can recognize 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 on the display. The exact error code provides useful information about the source of the problem, something a knowledgeable technician can use to provide solutions that much sooner.
Listed below are seven of the most frequent error codes you might encounter 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 projected cost to do so. Don't forget that while the price will ultimately hinge on the exact Nest model, you can anticipate paying between $75-$200 for repairs. This should include things like travel and labor costs on top of any specific components required to finish repairs.
e298 - Critical
This critical error code is limited to the latest 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 problem is dealt with.
Losing power to your Nest thermostat can be for several reasons. The wiring could have disconnected or become damaged, or a disconnection may have happened further along in your electrical system. This may be the circuit breaker, fuse box or system switch. A professional technician should inspect electrical connections and wiring until they uncover the root of the problem.
e294 - Critical
Critical error code e294 shows up 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 just a software issue. If that doesn’t work, they’ll examine 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 inserted into the connector with the proper amount of uncovered copper. Once they pinpoint the problem connector, it can be exchanged 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 sending power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat depletes and the thermostat will eventually turn off. Presuming the breakers are on, you can check a couple of other places before consulting a professional technician.
As 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 dealing with. You can detach the thermostat from its base and supply power by using a USB cable. If it presents error code 195, you should continue to visually check components like the wiring as well as your air conditioner’s air filter or drainage system. If you don’t find 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 may refer to an overcurrent problem, which means the wiring is getting more power than necessary. This can stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. The technician will cautiously examine and test the Nest’s electrical system to understand where the power is surging or why the thermostat thinks there’s an overcurrent problem.
Although this error code isn’t critical, it may still stop 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 the absence of one can block your Nest from getting enough power. You can inspect the Nest’s C connector for the presence of a C wire and adapt the wiring itself if there is. If not, you’ll need a Nest Power Connector.
With installation of a Nest Power Connector, you may notice error code E297 appear. This can be dealt with by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead be required 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 excessive power is being delivered inside the Nest’s wiring, it could damage internal components and could even be a fire hazard. If you see this error code appear on your Nest thermostat and want to protect from electrical damage, it’s recommended to shut the power off as soon as possible. You can then contact a professional technician with the proper experience diagnosing and solving electrical damage.
e73 - Critical
When your thermostat displays error code e73, it indicates that the Rc wire is not receiving power. This could be as straightforward as the breaker being turned off, but it could also be an issue with the wiring. After switching 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 a good idea to get in touch with a local professional.