A Honeywell smart thermostat is a great way to fine-tune how you use your heating and cooling. But like any utility, you could sometimes run across a problem. With the digital display, Honeywell smart thermostats can display an error code that certified technicians use to understand what's wrong. Here are several of the most common error codes you might see on your Honeywell smart thermostat.
Honeywell Error Code e42
You can receive this error code in the event that your home’s Wi-Fi internet did not provide an IP address for the thermostat to connect with. This can happen if your router does not execute the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically sends out the necessary IP address for your thermostat to link up.
How to Fix Honeywell Thermostat Error e42
You can clear error code e42 by confirming that your router has enabled DHCP. When it does, you might also need to power cycle the router and complete the initial setup process again with the thermostat. Doing so should ensure the DHCP is transmitted and connects to your smart thermostat.
Honeywell Error Code e02
Error code e02 appears if the password for accessing your home’s Wi-Fi router is not correct. When this error code appears for 30 seconds, the thermostat’s digital display should automatically transition 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 verify you’re entering the correct Wi-Fi password when setting up the thermostat.
Honeywell Thermostat Error 40
Error code 40 can appear when the thermostat is alerted that a heat pump or air conditioner’s monitoring system has detected a malfunction. Most often, this appears if the compressor isn’t working despite being instructed to. But this error code could also appear if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, triggered by poor airflow, can display this error code. Lastly, you could 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 inspect the air filter for signs of a clog, as well as the breakers and indoor unit’s blower for normal operation. If you turn the thermostat off and on again and error code 40 reappears, you should try to get a hold of an experienced technician.
Honeywell Error Code e43
If your Honeywell thermostat presents error code e43, it is failing to 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
Reboot the router by unplugging it and leaving it that way for about 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 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 appear on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A qualified technician can replace the sensor and restart the thermostat, which should take care of error code e1.
Honeywell Thermostat Error 11n
Error code 11n can appear when the thermostat can’t recognize a heating or cooling unit. This can mean that the equipment itself is faulty and unable to connect with 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 professional technician can use a voltmeter to assess if there’s a bad electrical connection. When the wiring on your existing HVAC system is bad, the technician can replace it. If the thermostat itself is the issue, it should probably be replaced.
Error Code e2 for Honeywell Thermostats
If you notice error code e2 pop up on your Honeywell smart thermostat, it might mean several different things. Sometimes, one of the sensors that detects the temperature isn’t operating 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
When the error code stems from sensor failure, a technician can troubleshoot and swap out the damaged sensor. When the problem comes from disconnected power, all you’ll have to do is make sure the router stays on during the setup process.