Using a Nest thermostat is one of the most convenient ways to optimize the day-to-day schedule of your heating and cooling. This smart thermostat can be taught your preferences and automatically make changes. But as you can expect, it won’t work well or at all if you see an error code on the display. The exact error code supplies useful information about the source of the problem, something a professional technician can use to offer solutions that much faster.
Here are seven of the most likely error codes you could find on your Nest thermostat. We’ll walk you through the basics of each error code on top of how you might fix it and the approximate cost to do so. Keep in mind that while the price will ultimately hinge on the specific Nest model, you can count on paying about $75-$200 for repairs. This should include things like travel and labor costs as well as any specific hardware necessary to complete 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. Since 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 resolved.
Losing power to your Nest thermostat can be for several reasons. The wiring might have disconnected or become damaged, or a disconnection might have happened further along in your electrical system. This could be the circuit breaker, fuse box or system switch. A trained technician should examine 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 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 problem. If that doesn’t work, they’ll review the wiring diagram of the thermostat and start checking connectors.
They’ll disconnect the power and gradually look at each wire, seeing to it that they are fully placed into the connector with the proper amount of exposed copper. When they locate the problem connector, it can be replaced 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 persists, the backup battery in your thermostat depletes and the thermostat will subsequently power down. In the event the breakers are on, you can inspect a few other places before calling a professional technician.
Since this error can deplete your thermostat’s battery, the first step could be providing enough power to figure out if this specific error code is what you’re working with. You can disconnect the thermostat from its base and provide power through a USB cable. In the event it presents error code 195, you can continue to visually check components like the wiring as well as your air conditioner’s air filter or drainage system. If you struggle to find anything wrong with these components, it's maybe best to contact a pro.
e103 - Critical
Another critical error code, e103 signifies an electrical malfunction 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 may stem from the breaker box, an error from the control board or because of a defective connection in the thermostat. The technician needs to cautiously investigate and test the Nest’s electrical system to understand where the power is surging or why the thermostat believes there’s an overcurrent problem.
While this error code isn’t critical, it could still prevent you from using the Nest thermostat how you prefer to. Error code n260 refers to the lack of a C wire or Nest Power Connector, as missing one can block your Nest from obtaining sufficient power. You can inspect the Nest’s C connector for the presence of a C wire and adjust 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 appear. This can be resolved by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead have 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 that's the result of an overcurrent. If too much power is being delivered inside the Nest’s wiring, it could damage internal components and can even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to guard against electrical damage, it’s recommended to turn the power off straightaway. You can then contact a professional technician with the appropriate experience detecting and resolving electrical malfunctions.
e73 - Critical
When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This will sometimes be as simple as the breaker being shut off, but it can also be something with the wiring. After switching off the power to your HVAC system and thermostat, you can visually examine the wires to make sure nothing is loose or damaged. If nothing seems to be out of place, it’s a good idea to contact a local professional.