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Solved: Honeywell Thermostat Error Codes

November 08, 2022

A Honeywell smart thermostat is an excellent way to fine-tune how you use your heating and cooling. But like any technology, you might sometimes run across a problem. With the digital display, Honeywell smart thermostats can display an error code that trained technicians use to understand what's going on. Here are some of the most known error codes you might see on your Honeywell smart thermostat.

Honeywell Thermostat Error e42

You can receive this error code in the event that your home’s Wi-Fi internet did not present an IP address for the thermostat to hook up to. This can happen if your router doesn't execute the Dynamic Host Configuration Protocol, or DHCP. This function automatically sends out the required IP address for your thermostat to link up.

How to Fix Honeywell Thermostat Error e42

You can fix error code e42 by making sure that your router has enabled DHCP. When it does, you might also have to power cycle the router and perform the setup process again with your thermostat. Completing this task should see to it that the DHCP is transmitted and connects to the smart thermostat.

Honeywell Thermostat Error e02

Error code e02 is displayed when the password for accessing your home’s Wi-Fi router is not correct. When this error code appears 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 need to do to clear error e02 is ensure you’re entering the correct Wi-Fi password when configuring the thermostat.

Honeywell Thermostat Error 40

Error code 40 can appear when the thermostat is notified that a heat pump or air conditioner’s monitoring system has identified a malfunction. For the most part, this appears if the compressor isn’t running despite being instructed to. But this error code can also surface if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, triggered by obstructed airflow, can render this error code. And 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 ordinary operation. If you restart the thermostat and error code 40 reappears, it's time to get in touch with 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 the Wi-Fi. This can 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 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 might notice error code e1 appear 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 could appear when the thermostat is unable to connect to a heating or cooling unit. This may mean that the equipment itself is faulty 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 qualified 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. In situations where the thermostat itself is the source of the error code, it will likely have to be replaced.

Honeywell Thermostat Error e2

If you’ve noticed error code e2 show up on your Honeywell smart thermostat, it could mean several different things. Sometimes, one of the sensors that detects the temperature isn’t working properly. In other cases, it means the router was disconnected from the outlet before the thermostat could complete the setup process.

How to Fix Honeywell Thermostat Error e2

In situations where the error code is a result of sensor failure, a technician should troubleshoot and replace the impacted sensor. When the problem stems from disconnected power, all you'll need to do is make sure the router stays on over the course of the setup process.