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 its digital display, Honeywell smart thermostats can display an error code that certified technicians will use to get a better sense of what's wrong. Here are several of the most likely error codes you might see on your Honeywell smart thermostat.
Honeywell Thermostat Error e42
You might encounter this error code when your home’s Wi-Fi internet did not provide an IP address for the thermostat to connect with. This can take place if a router doesn't perform the Dynamic Host Configuration Protocol, or DHCP. This function automatically transmits 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 is enabled for DHCP. When it does, you usually also have to power cycle the router and complete the initial setup process again with your thermostat. This should ensure the DHCP is transmitted and connects to the smart thermostat.
Honeywell Thermostat Error e02
Error code e02 occurs whenever the password for connecting to your home’s Wi-Fi router was incorrect. When this error code has appeared 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'll need to do to resolve 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 pop up when the thermostat is notified that a heat pump or air conditioner’s monitoring system has recognized a malfunction. For the most part, this appears when the compressor isn’t turning on despite being instructed to. But this error code can also appear if power is shut off from the outdoor unit for a long period of time. A “High Pressure Fault” error, induced by obstructed airflow, can render this error code. Lastly, you may encounter 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 regular operation. If you reset the thermostat and error code 40 reappears, you should try to get a hold of an experienced technician.
Honeywell Thermostat Error e43
If your Honeywell thermostat shows error code e43, it can’t 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 the wide area network (WAN).
How to Fix Honeywell Thermostat Error e43
Reset the router by unplugging it and leaving it that way for about 30 seconds. The thermostat could also be disconnected if you’ve recently switched the password or the Wi-Fi’s SSID, which is the name you create for it.
Honeywell Thermostat Error e1
Thermostats use sensors to identify the temperature outdoors and indoors. If a sensor malfunctions, you might see error code e1 show up on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A trained technician can change out the sensor and reboot the thermostat, which should take care of error code e1.
Honeywell Thermostat Error 11n
Error code 11n can appear when the thermostat is failing to connect to a heating or cooling unit. This may mean that the equipment itself is faulty and unable to maintain a connection to the thermostat. This can happen when the wiring is bad or even if the thermostat has failed.
How to Fix Honeywell Thermostat Error 11n
A qualified technician can employ a voltmeter to determine if there’s a poor electrical connection. If the wiring on your specific HVAC equipment is bad, the technician can replace it. When the thermostat itself is the issue, it will likely have to be replaced.
Honeywell Thermostat Error e2
If you see error code e2 appear on your Honeywell smart thermostat, it could mean a few different things. Sometimes, one of the sensors that detects the temperature isn’t functioning properly. In other cases, it means the router was disconnected from the outlet before the thermostat finished the setup process.
How to Fix Honeywell Thermostat Error e2
If the error code is a result of sensor failure, a technician will troubleshoot and swap out the impacted sensor. When the problem originates from disconnected power, all you'll need to do is make sure the router stays on during the setup process.