A Honeywell smart thermostat is an excellent way to optimize how you use your heating and cooling. But like any utility, you may occasionally run across a problem. With its digital display, Honeywell smart thermostats can show an error code that trained technicians will use to understand what's wrong. Here are some of the most likely error codes you may see on your Honeywell smart thermostat.
Honeywell Error Code e42
You can encounter this error code when your home’s Wi-Fi internet did not provide an IP address for the thermostat to hook up to. This can happen if a router doesn't complete the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically transmits the necessary IP address for your thermostat to connect.
How to Fix Honeywell Thermostat Error e42
You can resolve error code e42 by making sure that your router can complete the DHCP. Assuming it does, you usually also need to power cycle the router and perform the setup process again with the thermostat. Completing this task should ensure the DHCP is sent and connects to the smart thermostat.
Honeywell Error Code e02
Error code e02 occurs if the password for connecting to your home’s Wi-Fi router is not correct. 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 need to do to clear error e02 is verify you’re entering the correct Wi-Fi password when configuring the thermostat.
Honeywell Error Code 40
Error code 40 can appear when the thermostat is informed that a heat pump or air conditioner’s monitoring system has recognized a malfunction. For the most part, this happens when the compressor isn’t turning on despite being directed to. But this error code may also appear if power is disconnected from the outdoor unit for an extended period of time. A “High Pressure Fault” error, triggered by obstructed airflow, can lead to this error code. Lastly, you could encounter error code 40 if there’s a problem with the refrigerant, 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 ordinary operation. If you restart the thermostat and error code 40 reappears, it's time to get a hold of an experienced technician.
Honeywell Error Code e43
If the Honeywell thermostat shows error code e43, it can’t 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 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.
Error Code e1 for Honeywell Thermostats
Thermostats use sensors to identify the temperature outdoors and indoors. If a sensor malfunctions, you may notice error code e1 show up on your Honeywell smart thermostat.
How to Fix Honeywell Thermostat Error e1
A trained technician can swap out the sensor and reboot the thermostat, which should clear error code e1.
Honeywell Error Code 11n
Error code 11n could appear when the thermostat is failing to recognize a heating or cooling unit. This may mean that the equipment itself is faulty and unable to communicate 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 professional technician can use a voltmeter to assess if there’s a bad electrical connection. In situations where the wiring on your existing HVAC equipment is bad, the technician can replace it. In situations where the thermostat itself is the source of the error code, it should probably be replaced.
Honeywell Thermostat Error e2
If you’ve noticed error code e2 show up on your Honeywell smart thermostat, it might mean several different things. Sometimes, one of the sensors used to detect the temperature isn’t operating properly. Other times, it means the router was disconnected from the outlet before the thermostat could complete 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 replace the affected sensor. When the problem stems from disconnected power, all you’ll have to do is see to it that the router stays on over the course of the setup process.