A Honeywell smart thermostat is a great way to optimize how you use your HVAC system. But like any technology, you might sometimes run across a problem. With the digital display, Honeywell smart thermostats can display an error code that trained technicians will use to get a better sense of what's happening. Here are some of the most common error codes you could see on your Honeywell smart thermostat.
Error Code e42 for Honeywell Thermostats
You can see this error code when your home’s Wi-Fi connection did not provide an IP address for the thermostat to hook up to. This can occur if the router fails to complete the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically sends out the necessary IP address for your thermostat to connect to the Wi-Fi.
How to Fix Honeywell Thermostat Error e42
You can fix error code e42 by confirming that your router can complete the DHCP. Assuming it does, you usually also have to power cycle the router and repeat the initial setup process with your thermostat. Doing so should see to it that the DHCP is delivered and connects to the smart thermostat.
Error Code e02 for Honeywell Thermostats
Error code e02 is displayed when the password for communicating with your home’s Wi-Fi router was incorrect. After this error code has appeared for 30 seconds, the thermostat’s digital display will automatically progress to the Wi-Fi setup screen so you can try the password again.
How to Fix Honeywell Thermostat Error e02
All you'll need to do to clear error e02 is verify you’re entering the correct Wi-Fi password when configuring the thermostat.
Honeywell Error Code 40
Error code 40 can show up when the thermostat is informed that a heat pump or air conditioner’s monitoring system has recognized a malfunction. Most commonly, this happens when the compressor isn’t working despite being directed to. But this error code can also appear if power is disconnected from the outdoor unit for an extended period of time. A “High Pressure Fault” error, caused by blocked airflow, can lead to this error code. Finally, you might see error code 40 if there’s an issue with the refrigerant, the outdoor unit’s fan motor or the motor’s starting capacitor.
How to Fix Honeywell Thermostat Error 40
You can check 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, it’s best to get in touch with an experienced technician.
Error Code e43 for Honeywell Thermostats
If a Honeywell thermostat displays error code e43, it is unable to communicate with the router, and by extension the Wi-Fi. This may 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 a short period. The thermostat could also be disconnected if you recently switched the password or the Wi-Fi’s SSID, which is the name you provide it.
Error Code e1 for Honeywell Thermostats
Thermostats use sensors to determine the temperature outdoors and indoors. If a sensor malfunctions, you might see error code e1 turn up on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A qualified technician can change out the sensor and restart the thermostat, which should resolve error code e1.
Honeywell Thermostat Error 11n
Error code 11n can appear in situations where the thermostat can’t detect a heating or cooling unit. This might mean that the equipment itself is malfunctioning and unable to maintain a connection to the thermostat. This can happen when the wiring is damaged or even if the thermostat is faulty.
How to Fix Honeywell Thermostat Error 11n
A professional technician can employ a voltmeter to find out if there’s a poor electrical connection. If the wiring on your specific HVAC equipment is bad, the technician can replace it. If the thermostat itself is the source of the error code, it should probably be replaced.
Error Code e2 for Honeywell Thermostats
If you see error code e2 show up on your Honeywell smart thermostat, it could mean a few different things. In some cases, one of the sensors used to detect the temperature isn’t functioning correctly. Other times, it means the router was disconnected from its power source before the thermostat completed the setup process.
How to Fix Honeywell Thermostat Error e2
In situations where the error code stems from sensor failure, a technician should troubleshoot and swap out the damaged sensor. When the problem comes from disconnected power, all you'll need to do is make sure the router stays on throughout the setup process.