A Honeywell smart thermostat is a great way to optimize how you use your HVAC system. But like any utility, you may sometimes run into a problem. With a 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 some of the most common error codes you may see on your Honeywell smart thermostat.
Honeywell Thermostat Error e42
You can see this error code when your home’s Wi-Fi internet did not provide an IP address for the thermostat to connect to. This can occur if a 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 verifying that your router is enabled for DHCP. Assuming it does, you usually also have to power cycle the router and complete the initial setup process again with your thermostat. Completing this task should ensure the DHCP is delivered and connects to your smart thermostat.
Honeywell Thermostat Error e02
Error code e02 appears whenever the password for communicating with your home’s Wi-Fi router is incorrect. Once this error code has appeared for 30 seconds, the thermostat’s digital display automatically transitions 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 resolve error e02 is make sure you’re putting in the correct Wi-Fi password when configuring 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 identified a malfunction. For the most part, this appears once the compressor isn’t working despite being instructed to. But this error code could also show up if power is shut off from the outdoor unit for an extended period of time. A “High Pressure Fault” error, caused by obstructed airflow, can lead to this error code. Lastly, you may encounter error code 40 if there’s something wrong 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 regular operation. If you reset the thermostat and error code 40 reappears, you should try to get in touch with an experienced technician.
Honeywell Thermostat Error e43
If your Honeywell thermostat shows error code e43, it can’t communicate with the router, and by extension your Wi-Fi. This might 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
Reset the router by unplugging it and leaving it that way for about 30 seconds. The thermostat could also be disconnected if you have recently updated the password or the Wi-Fi’s SSID, which is the name you give it.
Honeywell Thermostat Error e1
Thermostats employ sensors to determine the temperature outdoors and indoors. If a sensor malfunctions, you might see error code e1 appear on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A skilled technician can replace the sensor and reboot the thermostat, which should clear error code e1.
Honeywell Thermostat Error 11n
Error code 11n may appear in situations where the thermostat can’t detect a heating or cooling unit. This may mean that the equipment itself is faulty and unable to maintain a connection to the thermostat. This sometimes happens when the wiring is damaged or even if the thermostat is faulty.
How to Fix Honeywell Thermostat Error 11n
A qualified technician can use a voltmeter to find out if there’s a bad 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 source of the error code, it should probably be replaced.
Honeywell Thermostat Error e2
If you see error code e2 show up on your Honeywell smart thermostat, it might mean several different things. For example, one of the sensors used to detect the temperature isn’t functioning properly. In other instances, it means the router was disconnected from its power source before the thermostat completed the setup process.
How to Fix Honeywell Thermostat Error e2
When the error code is a result of sensor failure, a technician should troubleshoot and swap out the damaged sensor. Any time the problem originates from disconnected power, all you have to do is verify the router stays on over the course of the setup process.