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 optimize the daily schedule of your HVAC system. This smart thermostat can learn your preferences and automatically make improvements. 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 offers useful information about the root of the problem, something a knowledgeable technician can use to offer solutions that much sooner.

Listed below are seven of the most common error codes you could encounter on your Nest thermostat. We’ll review the basics of each error code as well as how you can address it and the estimated cost to do so. Remember that while the costs will ultimately be dependent on the specific Nest model, you can expect to pay about $75-$200 for repairs. This should include travel and labor costs along with any specific hardware 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 disconnected from the system. Because this is a critical power error, the thermostat will switch to the backup battery system. The error message will continue to be displayed 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 could have happened further along in the electrical system. This may be the circuit breaker, fuse box or system switch. A knowledgeable technician can inspect 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 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 error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin looking at connectors.

They’ll shut off the power and slowly look at each wire, ensuring they are fully attached into the connector with the proper amount of bare copper. After they locate the damaged connector, it can be exchanged for a new one.

e195 - Critical

This critical error code can surface when the weather outside is particularly hot. The HVAC system can fail and stop giving power to your Nest thermostat. When this problem lingers, the backup battery in your thermostat drains and the thermostat will eventually turn off. Assuming the breakers are on, you can inspect a few other places before consulting a professional technician.

Because this error can deplete your thermostat’s battery, the first step might be restoring enough power to figure out if this specific error code is what you’re dealing with. You can detach the thermostat from its base and deliver power with a USB cable. In the event it reveals error code 195, you may continue to visually inspect components such as the wiring as well as your air conditioner’s air filter or drainage system. If you don’t detect anything wrong with these components, it will probably be best to call a pro.

e103 - Critical

Another critical error code, e103 indicates an electrical error with your Nest thermostat. More specifically, e103 may refer to an overcurrent problem, which means the wiring is getting more power than necessary. This may stem from the breaker box, an error from the control board or because of a faulty connection in the thermostat. The technician can carefully inspect and test the Nest’s electrical system to determine where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

Although this error code isn’t critical, it can still keep 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 not having one can block your Nest from getting 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’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 has already been installed, you’ll instead have 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 too much power is transported 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 protect from electrical damage, it’s suggested to turn the power off straightaway. You can then get a hold of a professional technician with the appropriate experience identifying and resolving electrical problems.

e73 - Critical

When your thermostat displays error code e73, it signifies that the Rc wire is not getting power. This could be as straightforward as the breaker being turned 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 nothing is loose or damaged. If nothing appears to be out of place, it’s a good idea to speak with a local professional.