I have the insurance version of the Medela PISA, a double electric. It works just fine as a double, but I have noticed if I ever try to pump just one side the suction sucks (ha, no pun intended!). There is a little plug you are meant to put in the side you aren't using, but there is a tiny hole in the plug. When I pumped one side yesterday (I wanted to leave one side for the baby when she woke up) there was very little suction unless I put my finger over the tiny hole, in which case there was too much suction. Am I doing something wrong here?

I just ordered a manual pump through insurance for this kind of situation anyway so it probably won't come up very often anymore anyway, just curious.