You can turn off your Honeywell Security System by disconnecting its backup battery and unplugging its transformer. This will completely power down the panel so that you can safely make changes. When powering the system back on, you should connect the transformer before the backup battery. There are many reasons why you might need to power down your Resideo System (formerly Honeywell). You might need to install an alarm monitoring communicator. You might be replacing a PROM Chip on the main board. Or maybe the system isn't working properly, and you are trying a reboot as a troubleshooting step. Regardless of the reason, powering down a Resideo Panel is very easy. You just need to disconnect the backup battery and unplug the transformer. Please note that many wireless Resideo Panels will have a system reboot option found within the Master Tools Menu. This will have the panel reboot without disconnecting anything. The Panel will power back on immediately, so this isn't useful if you need to make hardware changes. But this is effectively the same as powering down the panel for a troubleshooting step. You will need the Master Code for the system to access this menu and reboot in this manner. Complete the following steps to power down your Resideo System: 1. Unplug the backup battery. Go to your panel and disconnect the backup battery. If you have a hardwired Resideo Panel, it is likely hidden somewhere inside a beige metal enclosure. Popular locations for hardwired panels include basements, attics and storage closets. You can find the backup battery in this enclosure. Wireless panels will need to be opened up to disconnect the backup battery. You may need a screwdriver to complete this process. 2. Disconnect the power transformer. Next disconnect the power transformer. You unplug it from the wall outlet. If you have a Honeywell LT-Cable, you can just disconnect the barrel connector. This is effectively the same as unplugging the transformer. 3. Confirm the shutdown. Check the display screen for your panel or its keypad. The screen should be blank. This indicates that the system has been powered down successfully. You can then proceed to make any necessary hardware changes.