A Honeywell smart thermostat is an excellent way to fine-tune how you use your HVAC system. But like any utility, you could occasionally run into a problem. With the digital display, Honeywell smart thermostats can display an error code that professional technicians can use to get a better sense of what's wrong. Here are a few of the most likely error codes you might see on your Honeywell smart thermostat.
Error Code e42 for Honeywell Thermostats
You might receive this error code when your home’s Wi-Fi internet did not provide an IP address for the thermostat to connect to. This can take place if the router does not complete the Dynamic Host Configuration Protocol, or DHCP. This process automatically transmits the necessary IP address for your thermostat to connect.
How to Fix Honeywell Thermostat Error e42
You can clear error code e42 by verifying that your router can complete the DHCP. When it does, you may also have to power cycle the router and perform the setup process again with the thermostat. This should see to it that the DHCP is sent and connects to your smart thermostat.
Error Code e02 for Honeywell Thermostats
Error code e02 occurs when the password for accessing your home’s Wi-Fi router is incorrect. 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 resolve error e02 is make sure you’re putting in the correct Wi-Fi password when setting up the thermostat.
Error Code 40 for Honeywell Thermostats
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 once the compressor isn’t running despite being instructed to. But this error code may also surface if power is shut off from the outdoor unit for a long period of time. A “High Pressure Fault” error, caused by blocked airflow, can render this error code. Lastly, you might encounter error code 40 if there’s an issue with the coolant, the outdoor unit’s fan motor or the motor’s starting capacitor.
How to Fix Honeywell Thermostat Error 40
You can inspect the air filter for signs of a clog, as well as the breakers and indoor unit’s blower for normal operation. If you restart the thermostat and error code 40 reappears, it's time to contact an experienced technician.
Honeywell Error Code e43
If the Honeywell thermostat shows 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 the wide area network (WAN).
How to Fix Honeywell Thermostat Error e43
Restart the router by unplugging it and leaving it that way for around 30 seconds. The thermostat might also be disconnected if you have recently updated the password or the Wi-Fi’s SSID, which is the name you create for it.
Error Code e1 for Honeywell Thermostats
Thermostats use sensors to determine the temperature outdoors and indoors. If a sensor malfunctions, you could notice error code e1 appear on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A trained technician can change out the sensor and restart the thermostat, which should clear error code e1.
Error Code 11n for Honeywell Thermostats
Error code 11n can appear when the thermostat is unable to detect a heating or cooling unit. This might mean that the equipment itself is faulty and unable to communicate with the thermostat. This can happen when the wiring is defective 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 bad electrical connection. If the wiring on your specific HVAC equipment is bad, the technician can replace it. In situations where the thermostat itself is the issue, it should probably be replaced.
Error Code e2 for Honeywell Thermostats
If you see error code e2 appear on your Honeywell smart thermostat, it can mean a few different things. For example, one of the sensors responsible for detecting the temperature isn’t functioning properly. Other times, it means the router was disconnected from power before the thermostat finished the setup process.
How to Fix Honeywell Thermostat Error e2
When the error code stems from sensor failure, a technician can troubleshoot and replace the affected sensor. Any time the problem originates from disconnected power, all you have to do is verify the router stays on throughout the setup process.