Pressure Switch Adjustment Home › Forums › Public Forums › General Plumbing › Pressure Switch Adjustment This topic has 1 reply, 2 voices, and was last updated 21 years ago by Robert Stephen Morton. Viewing 1 reply thread Author Posts 17 Apr 2003 at 12:38 am #276520 MasterPlumbersKeymaster On my pressure tank based water system the pressure switch has two springs that determine the low and high pressure setting in order to turn the well pump on and off. Which spring is which? There is a big one and a small one. 17 Apr 2003 at 1:50 am #294308 Robert Stephen MortonParticipant PeterA, Be extremely careful in this area because there is live power, call an electrician.Bob 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