A Honeywell smart thermostat is an excellent way to fine-tune how you use your HVAC system. But like any mechanical system, you might occasionally run into a problem. With its digital display, Honeywell smart thermostats can show an error code that trained technicians will use to understand what's happening. Here are a few of the most known 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 provide an IP address for the thermostat to connect to. This can happen if your router doesn't complete the Dynamic Host Configuration Protocol, or DHCP. This function automatically transmits the necessary IP address for your thermostat to connect to the Wi-Fi.
How to Fix Honeywell Thermostat Error e42
You can clear error code e42 by making sure that your router can complete the DHCP. Assuming it does, you may also have to power cycle the router and perform the setup process again with the thermostat. This should ensure the DHCP is delivered and connects to the smart thermostat.
Honeywell Error Code e02
Error code e02 occurs whenever the password for connecting to your home’s Wi-Fi router is incorrect. When this error code is displayed for 30 seconds, the thermostat’s digital display automatically transitions to the Wi-Fi setup screen so you can try the password again.
How to Fix Honeywell Thermostat Error e02
All you have to do to clear error e02 is ensure you’re typing the correct Wi-Fi password when configuring the thermostat.
Honeywell Error Code 40
Error code 40 can appear when the thermostat is alerted that a heat pump or air conditioner’s monitoring system has recognized a malfunction. For the most part, this happens if the compressor isn’t working despite being directed to. But this error code can also appear if power is disconnected from the outdoor unit for a lengthy period of time. A “High Pressure Fault” error, induced by blocked airflow, can display this error code. And finally, you may 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 check 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 your Honeywell thermostat shows error code e43, it is unable to communicate with the router, and by extension the 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
Restart the router by unplugging it and leaving it that way for around 30 seconds. The thermostat could also be disconnected if you’ve recently updated the password or the Wi-Fi’s SSID, which is the name you provide it.
Honeywell Error Code e1
Thermostats use sensors to detect the temperature outdoors and indoors. If a sensor breaks down, you might notice error code e1 appear on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A qualified technician can replace the sensor and reset the thermostat, which should resolve error code e1.
Error Code 11n for Honeywell Thermostats
Error code 11n may appear if the thermostat is failing to recognize 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 bad 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 faulty electrical connection. When the wiring on your specific HVAC system is bad, the technician can replace it. In situations where the thermostat itself is the problem, it will likely have to be replaced.
Error Code e2 for Honeywell Thermostats
If you see error code e2 show up on your Honeywell smart thermostat, it could mean a couple of different things. For example, one of the sensors that detects the temperature isn’t functioning properly. In other instances, it means the router was disconnected from power before the thermostat completed the setup process.
How to Fix Honeywell Thermostat Error e2
When the error code is caused by sensor failure, a technician should troubleshoot and swap out the affected sensor. When the problem stems from disconnected power, all you'll need to do is make sure the router remains on throughout the setup process.