Error Code E42: How to Fix This Honeywell Thermostat Code

A Honeywell smart thermostat is an excellent way to optimize how you use your HVAC system. But like any mechanical system, you may sometimes run into a problem. With a digital display, Honeywell smart thermostats can display an error code that professional technicians can use to figure out what's going on. Here are a few of the most likely error codes you may see on your Honeywell smart thermostat.

Error Code e42 for Honeywell Thermostats

You might see this error code in the event that your home’s Wi-Fi internet did not provide an IP address for the thermostat to connect with. This can happen if the router doesn't 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 has enabled DHCP. If it does, you may also have to power cycle the router and repeat the initial setup process with your thermostat. Completing this task should see to it that the DHCP is transmitted and connects to the smart thermostat.

Honeywell Error Code e02

Error code e02 occurs if the password for accessing your home’s Wi-Fi router is not correct. 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 the password again.

How to Fix Honeywell Thermostat Error e02

All you'll need to do to clear error e02 is verify you’re putting in the correct Wi-Fi password when setting up the thermostat.

Honeywell Thermostat Error 40

Error code 40 can pop up when the thermostat is alerted that a heat pump or air conditioner’s monitoring system has detected a malfunction. Most commonly, this occurs when the compressor isn’t working despite being instructed to. But this error code can also show up if power is shut off from the outdoor unit for a lengthy 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 refrigerant, 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, it’s best to get in touch with an experienced technician.

Honeywell Error Code e43

If your Honeywell thermostat displays 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 the wide area network (WAN).

How to Fix Honeywell Thermostat Error e43

Reset the router by unplugging it and leaving it that way for around 30 seconds. The thermostat may also be disconnected if you have recently updated the password or the Wi-Fi’s SSID, which is the name you provide it.

Error Code e1 for Honeywell Thermostats

Thermostats employ sensors to determine the temperature outdoors and indoors. If a sensor fails, you could notice error code e1 appear on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

A trained technician can replace the sensor and restart the thermostat, which should take care of error code e1.

Error Code 11n for Honeywell Thermostats

Error code 11n could appear in situations where the thermostat can’t 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 use a voltmeter to determine if there’s a faulty electrical connection. If 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.

Honeywell Error Code e2

If you’ve noticed error code e2 appear on your Honeywell smart thermostat, it could mean several different things. For example, one of the sensors that detects the temperature isn’t functioning 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

If the error code is a result of sensor failure, a technician can troubleshoot and swap out the damaged sensor. When the problem stems from disconnected power, all you have to do is see to it that the router remains on during the setup process.