The E5 (or ES) alert indicates that an internal protector in your Sensi thermostat’s power supply has tripped and your thermostat may no longer effectively control the temperature inside your home. This problem will cause your thermostat to display an E5 - Call for Service error message. In addition, the temperature setting in your Sensi app may deviate from your desired indoor temperature by as much as 10⁰F, which may affect the temperature inside your home. This problem can be caused by a power surge, which can happen during a lightning storm, or by improper wiring of the Sensi thermostat during installation.
If you receive the E5 alert, contact Sensi Technical Support immediately or 888.605.7131 for more information.
You can temporarily disable the E5 error message on your thermostat display by disconnecting the c-wire (or common wire). To disconnect the c-wire, first turn off power to your heating and cooling equipment, then remove the cover from your Sensi thermostat. Next, locate and disconnect the wire from the C terminal (c-wire) and connect it to the L terminal. If a wire is already connected to the L terminal, you can tape the c-wire temporarily to the wall plate, making sure that it does not come into contact with any other terminals.
Disconnecting the c-wire in this manner will disable Wi-Fi so you will not be able to use your Sensi app to change your temperature remotely. However, your thermostat will continue to work to control the temperature in your home.
Important: Even if you temporarily disable the error message on your Sensi thermostat by disconnecting the c-wire, you should still contact Sensi Technical Support immediately at support@sensicomfort.com or 888.605.7131 for more information if you receive the E5 alert.