A Honeywell smart thermostat is an easy way to optimize how you use your HVAC system. But like any utility, you may occasionally experience a problem. With its digital display, Honeywell smart thermostats can provide an error code that professional technicians use to figure out what's going on. Here are a few of the most common error codes you could see on your Honeywell smart thermostat.
Honeywell Error Code e42
You can encounter this error code if your home’s Wi-Fi internet did not provide an IP address for the thermostat to connect to. This can happen if your router fails to complete the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically transmits the required 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 making sure that your router has enabled DHCP. If it does, you may also need to power cycle the router and repeat the initial setup process with the thermostat. Doing so should see to it that the DHCP is sent and connects to the smart thermostat.
Honeywell Thermostat Error e02
Error code e02 appears when the password for accessing your home’s Wi-Fi router was incorrect. After this error code appears for 30 seconds, the thermostat’s digital display automatically transitions to the Wi-Fi setup screen so you can attempt to enter 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 entering the correct Wi-Fi password when configuring the thermostat.
Honeywell Thermostat Error 40
Error code 40 can pop up when the thermostat is notified that a heat pump or air conditioner’s monitoring system has identified a malfunction. For the most part, this happens once the compressor isn’t turning on despite being instructed to. But this error code could also surface if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, induced by poor airflow, can lead to this error code. Lastly, you may see 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 reset the thermostat and error code 40 reappears, it’s best to get in touch with an experienced technician.
Honeywell Thermostat Error e43
If the Honeywell thermostat displays error code e43, it is unable to communicate with the router, and by extension your 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 could also be disconnected if you recently switched the password or the Wi-Fi’s SSID, which is the name you give it.
Error Code e1 for Honeywell Thermostats
Thermostats utilize sensors to determine the temperature outdoors and indoors. If a sensor malfunctions, you may see error code e1 show up on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A trained technician can change out the sensor and reboot the thermostat, which should clear error code e1.
Honeywell Thermostat Error 11n
Error code 11n can appear if the thermostat is failing to connect to a heating or cooling unit. This can 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 has failed.
How to Fix Honeywell Thermostat Error 11n
A licensed technician can use a voltmeter to find out if there’s a bad electrical connection. If the wiring on your specific HVAC system is bad, the technician can replace it. In situations where the thermostat itself is the problem, it should probably be replaced.
Honeywell Error Code e2
If you notice error code e2 pop up on your Honeywell smart thermostat, it could mean a couple of different things. For example, one of the sensors that detects the temperature isn’t operating properly. In other instances, it means the router was disconnected from the outlet before the thermostat could complete the setup process.
How to Fix Honeywell Thermostat Error e2
When the error code is a result of sensor failure, a technician will troubleshoot and swap out the affected sensor. If the problem comes from disconnected power, all you’ll have to do is verify the router remains on throughout the setup process.