expansion tank Home › Forums › Public Forums › General Plumbing › expansion tank This topic has 1 reply, 2 voices, and was last updated 18 years, 8 months ago by DUNBAR. Viewing 1 reply thread Author Posts 11 Sep 2005 at 4:51 am #277676 MasterPlumbersKeymaster I’m replacing a exp.tank that has a pin hole.Do i need to drain any water or bleed the pressure from its valve before disconnecting it ?And when I connect the new one ,do I have to pressurize it or is it factory pressured already? Thanks 11 Sep 2005 at 5:30 am #296881 DUNBARParticipant No. Just shut off the main cold water line and remove tank. Make sure that you gauge your working water pressure in the home. This way you can set the pressure of the tank to the working pressure of the home, preventing premature wear of the bladder. I do believe that Watts requires this on all of their expansion tanks. DUNBAR Website Moderator Author Posts Viewing 1 reply thread You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In