A Honeywell smart thermostat is an excellent way to optimize how you use your HVAC system. But like any utility, you could occasionally experience a problem. With a digital display, Honeywell smart thermostats can display an error code that trained technicians will use to get a better sense of what's happening. Here are a few of the most likely error codes you may see on your Honeywell smart thermostat.
Honeywell Thermostat Error e42
You may encounter this error code if your home’s Wi-Fi connection did not provide an IP address for the thermostat to hook up to. This can take place if a router doesn't execute the Dynamic Host Configuration Protocol, or DHCP. This function automatically sends out the required 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 confirming that your router can complete the DHCP. If it does, you may also need to power cycle the router and repeat the initial setup process with your thermostat. Doing so should ensure the DHCP is sent and connects to the smart thermostat.
Honeywell Thermostat Error e02
Error code e02 occurs if the password for connecting to your home’s Wi-Fi router was incorrect. 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 try the password again.
How to Fix Honeywell Thermostat Error e02
All you need to do to clear error e02 is verify you’re typing the correct Wi-Fi password when setting up the thermostat.
Honeywell Thermostat Error 40
Error code 40 can appear when the thermostat is informed that a heat pump or air conditioner’s monitoring system has detected a malfunction. Most commonly, this happens if the compressor isn’t turning on despite being directed to. But this error code can also surface if power is shut off from the outdoor unit for a long period of time. A “High Pressure Fault” error, triggered by blocked airflow, can render this error code. Lastly, you might see error code 40 if there’s a problem 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 restart the thermostat and error code 40 reappears, you should try to get a hold of an experienced technician.
Honeywell Thermostat Error e43
If a Honeywell thermostat presents error code e43, it can’t communicate with the router, and by extension the 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 might also be disconnected if you recently switched the password or the Wi-Fi’s SSID, which is the name you provide it.
Honeywell Thermostat Error e1
Thermostats employ sensors to identify the temperature outdoors and indoors. If a sensor fails, you could see 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 restart the thermostat, which should resolve error code e1.
Honeywell Thermostat Error 11n
Error code 11n could appear when the thermostat can’t recognize a heating or cooling unit. This may mean that the equipment itself is defective and unable to communicate 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 professional technician can use a voltmeter to assess if there’s a poor electrical connection. If the wiring on your specific HVAC system is bad, the technician can replace it. When the thermostat itself is the source of the error code, it will likely have to be replaced.
Honeywell Thermostat Error e2
If you notice error code e2 appear on your Honeywell smart thermostat, it could mean several different things. For example, one of the sensors that detects the temperature isn’t functioning like it should. Other times, it means the router was disconnected from its power source before the thermostat completed the setup process.
How to Fix Honeywell Thermostat Error e2
If the error code stems from sensor failure, a technician should troubleshoot and swap out the affected sensor. If the problem stems from disconnected power, all you'll need to do is see to it that the router stays on throughout the setup process.