A Honeywell smart thermostat is a great way to optimize how you use your home comfort system. But like any utility, you could sometimes run across a problem. With a digital display, Honeywell smart thermostats can show an error code that certified technicians can use to get a better sense of what's wrong. Here are some of the most likely error codes you might see on your Honeywell smart thermostat.
Honeywell Error Code e42
You may encounter this error code when your home’s Wi-Fi internet did not present an IP address for the thermostat to connect to. This can happen if a router doesn't complete the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically sends out the required IP address for your thermostat to connect.
How to Fix Honeywell Thermostat Error e42
You can resolve error code e42 by verifying that your router has enabled 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 transmitted and connects to your smart thermostat.
Error Code e02 for Honeywell Thermostats
Error code e02 occurs if the password for communicating with your home’s Wi-Fi router is not correct. After this error code appears for 30 seconds, the thermostat’s digital display should automatically transition to the Wi-Fi setup screen so you can try to enter the password again.
How to Fix Honeywell Thermostat Error e02
All you have to do to resolve error e02 is verify you’re typing the correct Wi-Fi password when configuring the thermostat.
Error Code 40 for Honeywell Thermostats
Error code 40 can appear when the thermostat is informed that a heat pump or air conditioner’s monitoring system has identified a malfunction. For the most part, this appears when the compressor isn’t turning on despite being instructed to. But this error code can also surface if power is shut off from the outdoor unit for a long period of time. A “High Pressure Fault” error, caused by poor airflow, can lead to this error code. Finally, 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 examine 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, you should try to get in touch with an experienced technician.
Honeywell Error Code e43
If your Honeywell thermostat presents error code e43, it can’t communicate with the router, and by extension the Wi-Fi. This could 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
Reboot the router by unplugging it and leaving it that way for about 30 seconds. The thermostat could also be disconnected if you’ve recently updated the password or the Wi-Fi’s SSID, which is the name you give it.
Honeywell Error Code e1
Thermostats use sensors to detect the temperature outdoors and indoors. If a sensor breaks down, you might see error code e1 appear on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A trained technician can swap out the sensor and reboot the thermostat, which should clear error code e1.
Error Code 11n for Honeywell Thermostats
Error code 11n can appear when the thermostat is failing to connect to a heating or cooling unit. This can mean that the equipment itself is defective and unable to connect with the thermostat. This sometimes happens 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 poor electrical connection. In situations where the wiring on your existing HVAC equipment is bad, the technician can replace it. When the thermostat itself is the problem, 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 several different things. In some cases, one of the sensors responsible for detecting the temperature isn’t functioning like it should. In other cases, it means the router was disconnected from the outlet before the thermostat finished the setup process.
How to Fix Honeywell Thermostat Error e2
In situations where the error code is caused by sensor failure, a technician can troubleshoot and swap out the impacted sensor. When the problem originates from disconnected power, all you’ll have to do is make sure the router stays on over the course of the setup process.