SENSI 1F87U-42WF, ST55 SMART THERMOSTAT Installation guide

SENSI 1F87U-42WF, ST55 SMART THERMOSTAT Installation guide

SENSI 1F87U-42WF, ST55 Table of Contents

  • Downloading the app and creating an account
  • Installing the Sensi thermostat
  • Connecting the Sensi thermostat
  • Troubleshooting
  • Notes


You Will Need

Gather this information before you begin installation for a smoother walk through

  • Sensi Passwor
  • Found on the back of the Welcome Guide, or back of the thermostat face plate labelled “Sensi Security Code”)
  • Wi-Fi Network Name/SSID
  • Make sure this is a 2.4GHz network.
  • Wi-Fi Network Password
  • Screwdriver
  • Hardware in Sensi Smart thermostat packaging 

Download the Sensi app

The smart Sensi thermostat is a WiFi enabled device. To properly install and configure the thermostat, you must use the Sensi app. To start the installation process, download the Sensi app to your smartphone or tablet. This is a free download. The Sensi app requires the following operating system (OS) software to download: Android (Google Play) version 5.0 or later iOS (Apple) version 10.0 or later

* Note that the Sensi app will ONLY show up in the iOS store if you search for "iPhone only". On iPad, change the search criteria in the App Store.

Create an account

When you download the Sensi app, you will be asked to create an account. This is necessary to access your thermostat remotely and use all the features that Sensi has to offer. Use a valid email address and password of your choice to create an account. Remember this email address and password. Your Sensi thermostat will be linked to this email address upon registration.


  1. Installation After downloading the Sensi app and creating an account, you can mount the thermostat on the wall and connect it to Wi-Fi. If no thermostat is listed yet, tap the "+" sign to add a thermostat. Then select the thermostat you purchased.
    • 1F87U-42WF series
    • ST55 seriesI Note: You can check your model number on the back of the thermostat's faceplate.
  2. Installation path After creating an account, log in and select your model. The app asks whether the thermostat is wall mounted or not. You select "No, needs to be installed" or "Yes, is on the wall". The first option goes through the entire installation process. If you haven't professionally installed this thermostat, choose this option. The second option is to just connect your thermostat to Wi-Fi. If your thermostat was installed by a professional and you only need to connect the Sensi thermostat to your home Wi-Fi network, choose this option. No, it needs to be installed. This option will guide you through the entire installation process, including identifying and connecting your cable and connecting to Wi-Fi. The Sensi app goes through the installation process step by step.
  3. Gather Tools and Package Contents Gather all necessary installation tools. Choose your thermostat
  4. Turn Off Power Turn off the power to your heating and air conditioning system before working on the thermostat wiring.
  5. Remove Old Thermostat Cover Remove the cover with a screwdriver or by pressing a push button. Some covers are removed while others need to be loosened with a screwdriver.
  6. Photograph Your Wiring THIS IS IMPORTANT. The Sensi app will ask you to take a photo of your existing thermostat and old cable in case you need it later. It can be useful for troubleshooting with our technical support team if needed. The captured photo will be saved in your camera or photo gallery.
  7. Throw Away Any Jumper Wires Sensi has jumper cables built-in and you don't need jumper cables from your old device.
  8. Choose Wire Terminals Select the terminal designation to which your old thermostat wires are attached here. The app will notify you if you have a valid configuration. If you get an invalid configuration message, you can learn more about compatibility at C-conductors or "common conductors" are required for heating, cooling and heat pump applications only. For more information about installing c-wire, see
  9. System Type Select the type of system you have.
  10. Label Your Wires Use the included label sticker to label your cables by removing the cables one at a time.
  11. Disconnect Wires and Remove Base Once all your cables are labeled, remove the old thermostat base from the wall.
  12. Install Sensi Base Use the provided mounting screws and secure the Sensi base to the wall.
  13. Connect the Wires Once the Sensi base is attached and secured to the wall, insert the cables into the clamps. Simply slide the cable into the connector slot. Use a screwdriver to tighten each cable
  14. Attach Cover Attaching the cover Press the front screen into the thermostat base.
  15. Turn On Power Turn on Restart the system..
  16. Connecting to Wi-Fi This section of the installation guide describes how to connect your thermostat to Wi-Fi. If you select "No, needs to be installed", the app will provide instructions on how to install and connect your thermostat before connecting to WiFi. If your Sensi-Thermostat has been installed by a professional, or if you have installed and connected your own Sensi-Thermostat but are not yet connected to WiFi, select "Yes, it's on the wall". This app connects your thermostat directly to WiFi.
    1. BROADCAST SENSI NETWORK On the thermostat, press Menu then Mode. The Wi-Fi icon in the upper-left corner will flash and 00, 11, or 22 will appear in the center of the thermostat. This determines which version of Sensi you have.
    2. CONNECT YOUR SENSI THERMOSTAT TO YOUR WI-FI NETWORK WITH THE SENSI APP Follow the step by step instructions in the Sensi app. Depending on your device operating system (iOS/Android), Sensi app version and your Sensi thermostat version, the WiFi connection process is slightly different. If you connect your iPhone/iPad and see 11 or 22 on the screen, you have the option to connect a thermostat to Apple HomeKit. Once you have connected to the Sensi network, enter the Sensi password printed in the welcome guide (or found on the back of the front panel of the thermostat as “Sensi security code”). You will then be connected to your Wi-Fi network.
  17. Name Thermostat You can choose a name or a custom name for your thermostat. Click next to continue.
  18. Register thermostat After successfully connecting the Sensi, the app will ask you to register the thermostat. You can select the "Find me" option or manually enter your street, city, state, zip code, country and time zone. Click next to continue.
  19. Contractor Information If a specialist installer has professionally installed your thermostat and is a registered Sensi partner, they can enter their phone number here. If no registered number is available, simply click Next to continue.
  20. Start Using Sensi Congratulations on the successful installation of Sensi. Click “Start using Sensi” to open the main application screen.


Connecting to Wi-Fi Troubleshooting

If you're having trouble connecting to WiFi, here are some tips to try:

  • Make sure the Sensi app is up to date and working with the latest version available in your app store.
  • Restart your smartphone.
  • Restart the router by unplugging it from the wall outlet for a few minutes, then turn it back on.
  • Once your router restarts and your WiFi network is able to access the internet again, make sure your phone is connected to your 2.4 GHz WiFi network.
  • If you're using an iPhone, make sure the keychain is turned on and home data is enabled for the Sensi app.
  • If you're using Android, access your phone's advanced Wi-Fi settings and turn off the switch to cellular data feature. (Depending on your Android device, it might say "Smart Network Switch" or "Avoid Bad Connections.")
  • It might be easier to disable the mobile data setting completely. You can find it in your connection settings.
  • Try using another smartphone or tablet. Just download the Sensi app and sign in to the app using the email address and password you used when creating your account.

Reconnecting to Wi-Fi

If you've changed your router or WiFi password, you'll need to reconnect the thermostat to WiFi. This depends on what smart device you are using. For more information about reconnecting, see our support article.

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Title : SENSI 1F87U-42WF, ST55 SMART THERMOSTAT Installation guide
Format : PDF
Pages : 56 Pages
Language : English
File Size : 5 MB


SENSI 1F87U-42WF, ST55 SMART THERMOSTAT Installation guide 

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