I bought a used ps 40 Winslow pellet stove, got it installed, and now cannot get it to continue running. Ready light gives one short blink and 1 long blink which would indicate vacuum switch. I pulled vacuum switch and if I suck on tube, I get continuity through switch. Using compressed air I blew into nipple on stove and it appears to be clear. The door and ash box seem tight. It has been a couple of years since this has been run. I jumped across vacuum switch and it burns fine. Any thoughts would be appreciated. Thanks.