Solved: Honeywell Thermostat Error Codes

November 08, 2022

A Honeywell smart thermostat is an excellent way to optimize how you use your HVAC system. But like any technology, you might occasionally experience a problem. With a digital display, Honeywell smart thermostats can provide an error code that professional technicians can use to get a better sense of what's happening. Here are a few of the most likely error codes you could see on your Honeywell smart thermostat.

Honeywell Thermostat Error e42

You may 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 take place if a router doesn't execute 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 clear error code e42 by confirming that your router can complete the DHCP. Assuming it does, you may also have to power cycle the router and perform the setup process again with your thermostat. This should see to it that the DHCP is delivered and connects to your smart thermostat.

Honeywell Thermostat Error e02

Error code e02 is displayed when the password for communicating with your home’s Wi-Fi router is incorrect. After this error code is displayed for 30 seconds, the thermostat’s digital display will automatically progress to the Wi-Fi setup screen so you can attempt to enter the password again.

How to Fix Honeywell Thermostat Error e02

All you have to do to solve error e02 is make sure you’re putting in the correct Wi-Fi password when setting up the thermostat.

Honeywell Thermostat Error 40

Error code 40 can show up when the thermostat is informed 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 working despite being directed to. But this error code could also show up if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, induced by obstructed airflow, can display this error code. Finally, you may experience error code 40 if there’s a problem with the coolant, 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 normal operation. If you restart the thermostat and error code 40 reappears, you should try to get in touch with an experienced technician.

Honeywell Thermostat Error e43

If the Honeywell thermostat displays error code e43, it can’t 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 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 may also be disconnected if you have recently switched the password or the Wi-Fi’s SSID, which is the name you give it.

Honeywell Thermostat Error e1

Thermostats utilize sensors to identify the temperature outdoors and indoors. If a sensor breaks down, you might see error code e1 turn up on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

A skilled technician can swap out the sensor and reboot the thermostat, which should clear error code e1.

Honeywell Thermostat Error 11n

Error code 11n can appear when the thermostat is failing to recognize a heating or cooling unit. This might mean that the equipment itself is defective and unable to maintain a connection to the thermostat. This can happen when the wiring is damaged or even if the thermostat has failed.

How to Fix Honeywell Thermostat Error 11n

A qualified technician can employ a voltmeter to find out if there’s a faulty electrical connection. In situations where the wiring on your type of HVAC equipment is bad, the technician can replace it. If 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 pop up on your Honeywell smart thermostat, it might mean several different things. Sometimes, one of the sensors used to detect the temperature isn’t working properly. In other cases, it means the router was disconnected from its power source before the thermostat completed the setup process.

How to Fix Honeywell Thermostat Error e2

When the error code stems from sensor failure, a technician will troubleshoot and swap out the affected sensor. Any time the problem originates from disconnected power, all you have to do is make sure the router remains on during the setup process.