A Honeywell smart thermostat is an excellent way to optimize how you use your home comfort system. But like any mechanical system, you could sometimes experience a problem. With a digital display, Honeywell smart thermostats can provide an error code that certified technicians use to understand what's wrong. Here are a few of the most likely error codes you might see on your Honeywell smart thermostat.
Honeywell Thermostat Error e42
You can see this error code if your home’s Wi-Fi internet did not supply an IP address for the thermostat to hook up to. This can occur if a router does not execute the Dynamic Host Configuration Protocol, or DHCP. This function automatically sends out the needed IP address for your thermostat to connect to the Wi-Fi.
How to Fix Honeywell Thermostat Error e42
You can resolve error code e42 by making sure that your router can complete the DHCP. Assuming it does, you may also need to power cycle the router and repeat the initial setup process with the thermostat. This should ensure the DHCP is delivered and connects to the smart thermostat.
Honeywell Thermostat Error e02
Error code e02 appears whenever the password for connecting to your home’s Wi-Fi router is not correct. After this error code is displayed for 30 seconds, the thermostat’s digital display will automatically progress to the Wi-Fi setup screen so you can attempt to enter the password again.
How to Fix Honeywell Thermostat Error e02
All you have to do to resolve error e02 is make sure you’re putting in the correct Wi-Fi password when setting up 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 recognized a malfunction. Most often, this appears if the compressor isn’t running despite being directed to. But this error code can also appear if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, caused by obstructed airflow, can lead to this error code. Finally, you might see error code 40 if there’s a problem with the refrigerant, 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 contact an experienced technician.
Honeywell Thermostat Error e43
If a Honeywell thermostat presents error code e43, it is unable 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 your wide area network (WAN).
How to Fix Honeywell Thermostat Error e43
Restart the router by unplugging it and leaving it that way for a short period. The thermostat may also be disconnected if you’ve recently switched the password or the Wi-Fi’s SSID, which is the name you give it.
Honeywell Thermostat Error e1
Thermostats use sensors to detect the temperature outdoors and indoors. If a sensor fails, you might notice error code e1 show up on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A trained technician can replace the sensor and reboot the thermostat, which should resolve error code e1.
Honeywell Thermostat Error 11n
Error code 11n can appear if the thermostat is unable to recognize a heating or cooling unit. This might mean that the equipment itself is defective and unable to communicate with the thermostat. This can happen when the wiring is defective or even if the thermostat has failed.
How to Fix Honeywell Thermostat Error 11n
A qualified technician can employ a voltmeter to find out if there’s a faulty electrical connection. In situations where the wiring on your type of HVAC system 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 pop up on your Honeywell smart thermostat, it can mean a few different things. In some cases, one of the sensors used to detect the temperature isn’t operating correctly. 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
In situations where the error code stems from sensor failure, a technician can troubleshoot and replace the damaged sensor. If the problem stems from disconnected power, all you'll need to do is verify the router remains on during the setup process.