A Honeywell smart thermostat is an excellent way to better manage how you use your home comfort system. But like any technology, you may sometimes run into a problem. With its digital display, Honeywell smart thermostats can display an error code that certified technicians can use to get a better sense of what's going on. Here are a few of the most known error codes you could see on your Honeywell smart thermostat.

Honeywell Thermostat Error e42

You can see this error code if your home’s Wi-Fi internet did not supply an IP address for the thermostat to connect with. This can take place if the router does not complete the Dynamic Host Configuration Protocol, or DHCP. This function automatically sends out the necessary IP address for your thermostat to connect.

How to Fix Honeywell Thermostat Error e42

You can fix error code e42 by confirming that your router has enabled DHCP. Assuming it does, you might also have to power cycle the router and complete the initial setup process again with the thermostat. This should see to it that the DHCP is sent and connects to the smart thermostat.

Honeywell Thermostat Error e02

Error code e02 appears if the password for connecting to your home’s Wi-Fi router is not correct. Once this error code has appeared for 30 seconds, the thermostat’s digital display should automatically transition to the Wi-Fi setup screen so you can try the password again.

How to Fix Honeywell Thermostat Error e02

All you need to do to clear error e02 is ensure you’re entering the correct Wi-Fi password when setting up the thermostat.

Honeywell Thermostat Error 40

Error code 40 can appear when the thermostat is notified that a heat pump or air conditioner’s monitoring system has detected a malfunction. For the most part, this appears if the compressor isn’t running despite being directed to. But this error code could also show up if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, caused by blocked airflow, can render this error code. Finally, you might encounter error code 40 if there’s something wrong with the refrigerant, the outdoor unit’s fan motor or the motor’s starting capacitor.

How to Fix Honeywell Thermostat Error 40

You can examine the air filter for signs of a clog, as well as the breakers and indoor unit’s blower for ordinary operation. If you turn the thermostat off and on again and error code 40 reappears, you should try to get in touch with an experienced technician.

Honeywell Thermostat Error e43

If a Honeywell thermostat presents error code e43, it can’t communicate with the router, and by extension the Wi-Fi. This can happen if the router’s ethernet cable isn’t plugged in or it isn’t communicating with your wide area network (WAN).

How to Fix Honeywell Thermostat Error e43

Reboot the router by unplugging it and leaving it that way for about 30 seconds. The thermostat may also be disconnected if you have recently updated the password or the Wi-Fi’s SSID, which is the name you provide it.

Honeywell Thermostat Error e1

Thermostats utilize sensors to identify the temperature outdoors and indoors. If a sensor fails, you might notice error code e1 show up on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

A trained technician can swap out the sensor and reset the thermostat, which should clear error code e1.

Honeywell Thermostat Error 11n

Error code 11n may appear in situations where the thermostat is failing to recognize a heating or cooling unit. This can mean that the equipment itself is defective and unable to maintain a connection to the thermostat. This can happen when the wiring is damaged or even if the thermostat has failed.

How to Fix Honeywell Thermostat Error 11n

A licensed technician can employ a voltmeter to find out if there’s a bad electrical connection. In situations where the wiring on your type of HVAC system is bad, the technician can replace it. In situations where the thermostat itself is the problem, it will likely have to be replaced.

Honeywell Thermostat Error e2

If you’ve noticed error code e2 pop up on your Honeywell smart thermostat, it could mean several different things. Sometimes, one of the sensors used to detect the temperature isn’t operating correctly. In other cases, it means the router was disconnected from power before the thermostat finished the setup process.

How to Fix Honeywell Thermostat Error e2

In situations where the error code is a result of sensor failure, a technician should troubleshoot and replace the affected sensor. When the problem comes from disconnected power, all you’ll have to do is verify the router stays on over the course of the setup process.