A Honeywell smart thermostat is a great way to optimize how you use your home comfort system. But like any mechanical system, you may occasionally run across a problem. With the digital display, Honeywell smart thermostats can provide an error code that professional technicians use to understand what's happening. Here are a few of the most common error codes you may see on your Honeywell smart thermostat.
Honeywell Thermostat Error e42
You can see this error code if your home’s Wi-Fi internet did not provide an IP address for the thermostat to connect with. This can happen if the router does not execute the Dynamic Host Configuration Protocol, or DHCP. This function automatically supplies the necessary IP address for your thermostat to link up.
How to Fix Honeywell Thermostat Error e42
You can clear error code e42 by confirming that your router is enabled for DHCP. When it does, you usually also need to power cycle the router and repeat the initial setup process with your thermostat. Completing this task should ensure the DHCP is transmitted and connects to the smart thermostat.
Honeywell Thermostat Error e02
Error code e02 is displayed whenever the password for accessing your home’s Wi-Fi router is incorrect. Once this error code is displayed for 30 seconds, the thermostat’s digital display should automatically transition to the Wi-Fi setup screen so you can attempt to enter the password again.
How to Fix Honeywell Thermostat Error e02
All you need to do to solve error e02 is verify you’re entering the correct Wi-Fi password when setting up the thermostat.
Honeywell Thermostat Error 40
Error code 40 can show up when the thermostat is notified that a heat pump or air conditioner’s monitoring system has identified a malfunction. Most often, this happens when the compressor isn’t working despite being instructed to. But this error code can also appear if power is shut off from the outdoor unit for an extended period of time. A “High Pressure Fault” error, triggered by blocked airflow, can display this error code. 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 restart the thermostat and error code 40 reappears, it's time to contact an experienced technician.
Honeywell Thermostat Error e43
If the Honeywell thermostat displays error code e43, it is unable to communicate with the router, and by extension the Wi-Fi. This might 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 a short period. The thermostat may also be disconnected if you have recently switched the password or the Wi-Fi’s SSID, which is the name you create for it.
Honeywell Thermostat Error e1
Thermostats utilize sensors to detect 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 swap out the sensor and restart the thermostat, which should clear error code e1.
Honeywell Thermostat Error 11n
Error code 11n can appear if the thermostat is unable to detect a heating or cooling unit. This might mean that the equipment itself is malfunctioning and unable to connect with the thermostat. This sometimes happens 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 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. When the thermostat itself is the problem, it will likely have to be replaced.
Honeywell Thermostat Error e2
If you see error code e2 appear on your Honeywell smart thermostat, it might mean a couple of different things. In some cases, one of the sensors responsible for detecting the temperature isn’t working properly. In other cases, it means the router was disconnected from its power source before the thermostat could complete 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 damaged sensor. When the problem comes from disconnected power, all you’ll have to do is verify the router stays on over the course of the setup process.