WT540 Module Home › Forums › Trade Technical & Spare Parts Forums › Trade Technical Enquiries › WT540 Module This topic has 0 replies, 1 voice, and was last updated 12 years, 9 months ago by aqua_serve. Viewing 1 post (of 1 total) Author Posts July 8, 2013 at 7:08 am #76120 aqua_serveParticipant Hi Guys, Just a quick question. I wonder if any of you could tell me what would cause the relay identified as ‘K3’ on this board to fail. Any advice would be appreciated. Mark Author Posts Viewing 1 post (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In