Kent Ace 7 RO is making a continuous beep... It has been one year only & being a small family, my usages of RO is very less... so why it's giving beep signal... I assume it's asking me to change the filter but why I have to change it so early while I am using an external filter also... this external filter was recommended by person who came for installation & demo of product after purchase... Request someone to help me please...