I just bought a Fissler pressure cooker and attempted to test it according to the manual directions. I filled it half full of water and brought that to a boil, attached the lid and then waited for the automatic valve to close.....and waited...and waited. Just to see if I was crazy I ran a timer and after 10 minutes it still hadn't reached the first pressure level. I checked the valves for adequate movement, removed and reset the gasket etc. Am I not waiting long enough or does this sound like one of the valves is defective?