I have two pumps... Medela Freestyle bought through some FSA money I needed to burn, and an Ameda Purely Yours sent by the insurance company. I was using the Freestyle, but once I came back to work last week it seemed like I got less milk every day. So, yesterday I broke out the Purely Yours to give it a shot.
I just used it for the fourth time... The diaphragm in one flange sometimes collapses a bit more with each pump until it is completely collapsed. Most of the time the diaphragms only collapse a little and then fully expand again before the next pump... but twice now it one side has done the thing where it collapses more and more until all the air has been sucked out of the diaphragm. I tried swapping the diaphragm out for a new one, and reseating the hard plastic cap thingie. I didn't try switching the valve that sits in the bottle opening because I didn't want to mess with the milk in the middle of pumping, but other than that I am not sure what else to try.
Any ideas what is causing that?