Hello fellow firefighters, I am new to the forum, glad to have joined, and am hoping someone here can help me out. My Volunteer Department purchased all new Scott 4500 Airpacks about 3 years ago. We have had no problems whatsoever with them until now. The other day i was going through a few of them and doing regular checks (changing batteries....etc) and noticed that after one of them comes on and the indicator for air level and battery go off, i get a red light in the bottom left corner of the regulator display that blinks rapidly. Looked in the book and couldn't find anything on this. I have tried to call Scott Tech support and can not get ahold of anyone. I was just wondering if anyone here might have an idea as to what is going on. Any help is greatly appreciated. Thank You