Operating a Nest thermostat is one of the easiest ways to optimize the daily schedule of your heating and cooling. This smart thermostat can learn your preferences and automatically make adjustments. But as you may expect, it won’t work properly or at all if you see an error code on the display. The precise error code provides useful information about the source of the problem, something a professional technician can use to offer solutions that much sooner.
Let's consider seven of the most common error codes you might encounter on your Nest thermostat. We’ll explain the basics of each error code along with how you can address it and the projected cost to do so. Keep in mind that while the costs will ultimately hinge on the exact Nest model, you can expect to pay between $75-$200 for repairs. This should also cover travel and labor costs along with any specific components necessary to complete 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. 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 problem is fixed.
Losing power to your Nest thermostat can be for a number of reasons. The wiring could have disconnected or become damaged, or a disconnection could have appeared 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 locate the root of the problem.
e294 - Critical
Critical error code e294 shows up when your Nest thermostat’s wiring should be reconfigured. More specifically, you’ll need the technician to reconfigure the R wire. They’ll first complete a factory reset of your thermostat to ensure it’s not merely a software problem. If that doesn’t work, they’ll examine the wiring diagram of the thermostat and begin looking at connectors.
They’ll shut off the power and progressively look at each wire, seeing to it that they are fully attached into the connector with the correct amount of bare copper. After they pinpoint the damaged connector, it can be exchanged for a new one.
e195 - Critical
This critical error code can appear when the weather outside is particularly hot. The HVAC system can fail and stop sending power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will eventually shut down. Assuming the breakers are on, you can check a few other places before contacting a professional technician.
As this error can consume your thermostat’s battery, the first step might be providing enough power to figure out if this specific error code is what you’re dealing with. You can separate the thermostat from its base and deliver power by using a USB cable. Assuming 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 uncover anything wrong with these components, it will probably be best to contact a pro.
e103 - Critical
Another critical error code, e103 suggests an electrical error with your Nest thermostat. More specifically, e103 can refer to an overcurrent problem, which means the wiring is getting more power than needed. This may stem from the breaker box, an error from the control board or thanks to a defective connection in the thermostat. A technician will carefully investigate and test the Nest’s electrical system to understand where the power is surging or why the thermostat is convinced there’s an overcurrent problem.
Even though this error code isn’t critical, it might still stop you from using the Nest thermostat like normal. Error code n260 concerns the lack of a C wire or Nest Power Connector, as not having one can block your Nest from receiving sufficient 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 might notice error code E297 show up. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector was already installed, you’ll instead need 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 excess power is being delivered using the Nest’s wiring, it may damage internal components and could even be a fire hazard. If you notice this error code appear on your Nest thermostat and want to guard against electrical damage, it’s a good idea to shut the power off as soon as you can. You can then contact a professional technician with the necessary experience identifying and solving electrical damage.
e73 - Critical
When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This will sometimes be as straightforward as the breaker being switched off, but it may also be something with the wiring. After turning off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure none of them are loose or damaged. If nothing looks to be out of place, it’s a good idea to speak with a local professional.