A Honeywell smart thermostat is a great way to better manage how you use your HVAC system. But like any mechanical system, you may occasionally run across a problem. With a digital display, Honeywell smart thermostats can provide an error code that certified technicians use to get a better sense of what's wrong. Here are a few of the most likely error codes you may see on your Honeywell smart thermostat.
Honeywell Error Code 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 with. This can occur if a router does not complete the Dynamic Host Configuration Protocol, or DHCP. This function 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 verifying that your router can complete the DHCP. Assuming it does, you usually also need to power cycle the router and complete the initial setup process again with the thermostat. Doing so should ensure the DHCP is sent and connects to the smart thermostat.
Error Code e02 for Honeywell Thermostats
Error code e02 appears whenever the password for accessing your home’s Wi-Fi router is not correct. Once this error code has appeared for 30 seconds, the thermostat’s digital display will automatically progress 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 solve error e02 is ensure you’re typing the correct Wi-Fi password when setting up the thermostat.
Honeywell Error Code 40
Error code 40 can show up when the thermostat is informed that a heat pump or air conditioner’s monitoring system has recognized a malfunction. Most commonly, this happens if the compressor isn’t running despite being instructed to. But this error code may also surface if power is shut off from the outdoor unit for an extended period of time. A “High Pressure Fault” error, induced by blocked airflow, can display this error code. Lastly, you could 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 inspect the air filter for signs of a clog, as well as the breakers and indoor unit’s blower for normal operation. If you restart the thermostat and error code 40 reappears, it's time to get in touch with an experienced technician.
Honeywell Thermostat Error e43
If a Honeywell thermostat displays error code e43, it can’t communicate with the router, and by extension your Wi-Fi. This could 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 around 30 seconds. The thermostat could also be disconnected if you have recently changed the password or the Wi-Fi’s SSID, which is the name you provide it.
Honeywell Thermostat Error e1
Thermostats utilize sensors to detect 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 qualified technician can change out the sensor and reset the thermostat, which should clear error code e1.
Honeywell Thermostat Error 11n
Error code 11n could appear when the thermostat is failing to detect a heating or cooling unit. This can mean that the equipment itself is defective and unable to communicate with the thermostat. This sometimes happens when the wiring is damaged or even if the thermostat has failed.
How to Fix Honeywell Thermostat Error 11n
A professional technician can use a voltmeter to find out if there’s a bad electrical connection. If the wiring on your type of HVAC equipment is bad, the technician can replace it. In situations where the thermostat itself is the issue, it will likely have to be replaced.
Honeywell Error Code e2
If you’ve noticed error code e2 show up on your Honeywell smart thermostat, it can mean a few different things. In some cases, one of the sensors responsible for detecting the temperature isn’t operating properly. 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 is caused by sensor failure, a technician can troubleshoot and switch out the affected sensor. When the problem stems from disconnected power, all you’ll have to do is see to it that the router remains on during the setup process.
