A Honeywell smart thermostat is an easy way to fine-tune how you use your HVAC system. But like any mechanical system, you could occasionally run into a problem. With a digital display, Honeywell smart thermostats can provide an error code that certified technicians will use to understand what's wrong. Here are some of the most likely error codes you may see on your Honeywell smart thermostat.
Honeywell Error Code e42
You can receive this error code if your home’s Wi-Fi connection did not present an IP address for the thermostat to connect with. This can occur if a router fails to complete the Dynamic Host Configuration Protocol, or DHCP. This process automatically supplies the necessary IP address for your thermostat to link up.
How to Fix Honeywell Thermostat Error e42
You can resolve error code e42 by confirming that your router has enabled DHCP. When it does, you may also have to power cycle the router and perform the setup process again with the 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 occurs if the password for connecting to your home’s Wi-Fi router was incorrect. After 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 to enter the password again.
How to Fix Honeywell Thermostat Error e02
All you'll need to do to resolve error e02 is ensure you’re typing the correct Wi-Fi password when setting up the thermostat.
Error Code 40 for Honeywell Thermostats
Error code 40 can appear when the thermostat is alerted that a heat pump or air conditioner’s monitoring system has identified a malfunction. Most commonly, this appears when the compressor isn’t running despite being directed to. But this error code may also show up if power is disconnected from the outdoor unit for an extended period of time. A “High Pressure Fault” error, triggered by obstructed airflow, can lead to this error code. Finally, you might experience 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 ordinary operation. If you turn the thermostat off and on again and error code 40 reappears, it's time to get in touch with an experienced technician.
Error Code e43 for Honeywell Thermostats
If a Honeywell thermostat shows 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 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 may also be disconnected if you have recently changed 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 identify the temperature outdoors and indoors. If a sensor malfunctions, you may notice error code e1 appear on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A qualified 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 in situations where the thermostat is failing to connect to a heating or cooling unit. This might mean that the equipment itself is faulty and unable to connect with the thermostat. This can happen when the wiring is bad or even if the thermostat is faulty.
How to Fix Honeywell Thermostat Error 11n
A qualified technician can employ a voltmeter to find out if there’s a bad electrical connection. When the wiring on your specific HVAC system is bad, the technician can replace it. If the thermostat itself is the problem, it should probably be replaced.
Honeywell Error Code e2
If you’ve noticed error code e2 pop up on your Honeywell smart thermostat, it can mean a couple of different things. Sometimes, one of the sensors used to detect the temperature isn’t working 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 stems from sensor failure, a technician should troubleshoot and swap out the damaged sensor. If the problem originates from disconnected power, all you'll need to do is make sure the router stays on over the course of the setup process.
