I have an issue that I'd like to rectify and was hoping for some comments. I have a Quattro that proves pilot before prepurging which is causing the board to time out before the pressure switch gets a chance to close. No crack in the heat exchanger and the pressure switch is good. I also checked for any seal issues in the draft motor assembly and box and all appears fine. Current PS is .52" of WC and I'm thinking of reducing that to solve the issue. Any comments or suggestions?