Help CenterThe LED on a the sensor should constantly flash within the first few seconds after you turn it on and then stop flashing. If your window or door sensor led is constantly flashing and not working properly with the alarm system, it means that the battery needs replacing. In this video i will show you how to replace the battery in the OSI Alarm Contact Sensor!🙂
Important: To replace the battery please follow the steps below. You will need one 2450 3V Lithium Coin battery. This is available at any major department store and can also be purchased for approx $5.00 to $7.00 from Amazon for a pack of two or $10 to $20 for a pack of 6 (depending on the brand). We recommend Energizer, Durcell, or Amazon Basics brand.
Step 1: Pry the sensor off with a screw drive. (there is no need to remove the sensor from the 3M adhesive tape)
Step 2: Press the rear tamper switch several times (to discharge the residual power in the capacitor component)
Step 3: Replace the battery with a brand new 2450 3V Lithium Coin battery . It is important that it is replaced with a brand new battery.
When you have replaced the battery, keep the sensor off for a few minutes then turn it back on to test the sensor.
Please follow step by step video tutorial below on how to replace contact sensor battery!