Hi, I purchased an extra ir sensor for my lounge, all added into system no prob, however when I do a walk test every so often which I like to do just to confirm everything is working, when I walk around room or even wave my arms like a looney in front of it nothing happens, all other sensors and door sensors register on walk test fine, when I go into menu and press add sensor then press button on it, it tels me it's all ready added, the only way I can get it to beep on walk test is to delete it from system, then install as new again then it beeps on walk test, this leaves me wondering if it's actually working when I come out of menu.