Solved: Honeywell Thermostat Error Codes

November 08, 2022

A Honeywell smart thermostat is an excellent way to better manage how you use your heating and cooling. But like any technology, you may sometimes run into a problem. With its digital display, Honeywell smart thermostats can provide an error code that trained technicians use to get a better sense of what's happening. Here are a few of the most likely error codes you might see on your Honeywell smart thermostat.

Honeywell Thermostat Error e42

You may receive this error code when your home’s Wi-Fi connection did not provide an IP address for the thermostat to connect to. This can happen if a router doesn't complete the Dynamic Host Configuration Protocol, or DHCP. This process automatically sends out the necessary IP address for your thermostat to connect to the Wi-Fi.

How to Fix Honeywell Thermostat Error e42

You can fix error code e42 by verifying that your router is enabled for DHCP. When it does, you may also need to power cycle the router and perform the setup process again with the thermostat. This should see to it that the DHCP is delivered and connects to your smart thermostat.

Honeywell Thermostat Error e02

Error code e02 occurs whenever the password for accessing your home’s Wi-Fi router is not correct. After this error code has appeared for 30 seconds, the thermostat’s digital display will automatically progress 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 solve error e02 is ensure you’re putting in the correct Wi-Fi password when configuring 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 recognized a malfunction. For the most part, this occurs once the compressor isn’t running despite being directed to. But this error code may also appear if power is shut off from the outdoor unit for a long period of time. A “High Pressure Fault” error, induced by blocked airflow, can display this error code. Finally, you could encounter error code 40 if there’s an issue 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 ordinary operation. If you reset the thermostat and error code 40 reappears, it’s best to contact an experienced technician.

Honeywell Thermostat Error e43

If your Honeywell thermostat presents error code e43, it is failing to communicate with the router, and by extension your Wi-Fi. This may 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

Restart the router by unplugging it and leaving it that way for a short period. The thermostat could also be disconnected if you recently switched the password or the Wi-Fi’s SSID, which is the name you give it.

Honeywell Thermostat Error e1

Thermostats employ 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 skilled technician can replace the sensor and restart the thermostat, which should clear error code e1.

Honeywell Thermostat Error 11n

Error code 11n can appear in situations where the thermostat is failing to connect to a heating or cooling unit. This may mean that the equipment itself is defective and unable to connect with the thermostat. This can happen when the wiring is damaged or even if the thermostat is faulty.

How to Fix Honeywell Thermostat Error 11n

A professional technician can utilize a voltmeter to assess if there’s a faulty electrical connection. When the wiring on your type of HVAC equipment is bad, the technician can replace it. If the thermostat itself is the problem, it should probably be replaced.

Honeywell Thermostat Error e2

If you see error code e2 appear on your Honeywell smart thermostat, it might mean several different things. For example, one of the sensors responsible for detecting the temperature isn’t working correctly. In other instances, it means the router was disconnected from the outlet before the thermostat completed the setup process.

How to Fix Honeywell Thermostat Error e2

In situations where the error code is caused by sensor failure, a technician will troubleshoot and replace the impacted sensor. If the problem originates from disconnected power, all you’ll have to do is verify the router stays on throughout the setup process.