A Honeywell smart thermostat is a great way to better manage how you use your heating and cooling. But like any mechanical system, you could occasionally run across a problem. With a digital display, Honeywell smart thermostats can display an error code that trained technicians use to figure out what's going on. Here are some of the most common error codes you could see on your Honeywell smart thermostat.
Honeywell Thermostat Error e42
You might see this error code if your home’s Wi-Fi connection did not present an IP address for the thermostat to connect to. This can occur if your router doesn't perform the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically supplies 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. When it does, you usually also have to power cycle the router and repeat the initial setup process with your thermostat. Doing so should see to it that the DHCP is transmitted and connects to the smart thermostat.
Honeywell Thermostat Error e02
Error code e02 appears when the password for connecting to your home’s Wi-Fi router was incorrect. Once this error code appears for 30 seconds, the thermostat’s digital display automatically transitions to the Wi-Fi setup screen so you can try to enter the password again.
How to Fix Honeywell Thermostat Error e02
All you need to do to clear error e02 is make sure you’re entering the correct Wi-Fi password when setting up 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. 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. And finally, you might 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, it's time to get a hold of an experienced technician.
Honeywell Thermostat Error e43
If a Honeywell thermostat presents error code e43, it is failing to 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 your 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’ve recently updated the password or the Wi-Fi’s SSID, which is the name you create for it.
Honeywell Thermostat Error e1
Thermostats utilize sensors to determine the temperature outdoors and indoors. If a sensor breaks down, you may see error code e1 turn up on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A trained technician can replace the sensor and reset the thermostat, which should clear error code e1.
Honeywell Thermostat Error 11n
Error code 11n can appear in situations where the thermostat is failing to connect to a heating or cooling unit. This might mean that the equipment itself is defective and unable to connect with the thermostat. This can happen when the wiring is defective or even if the thermostat is faulty.
How to Fix Honeywell Thermostat Error 11n
A licensed technician can employ a voltmeter to determine if there’s a bad electrical connection. In situations where the wiring on your specific HVAC system is bad, the technician can replace it. When the thermostat itself is the problem, it should probably be replaced.
Honeywell Thermostat Error e2
If you’ve noticed error code e2 appear on your Honeywell smart thermostat, it could mean several different things. Sometimes, one of the sensors that detects the temperature isn’t working 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 stems from sensor failure, a technician should troubleshoot and replace the impacted sensor. If the problem stems from disconnected power, all you'll need to do is verify the router remains on over the course of the setup process.