Oh, I use it as a slow cooker all the time! I LOVE that function of it. I find that it works the same heat wise as my old skool slow cooker. The reason I prefer using it to my old skool slow cooker is because of the lid. I know lots of people LOVE when their house is filled with the delicious aroma of cooking dinner all day long, but I'm home all day and having such a food filled aroma tempt me all day is too hard.
So i prefer that lid because it holds in more of the smells.
That said, I do use the pressure cooker function more often.
For beans, I always presoak overnight. I know with the IP you don't *have* to but it's easy and plus presoaking increases the nutritional value of beans (or more specifically makes the nutrients more accessible to your body).
Then I do the manual setting (I've never done the bean setting) for between 20 and 25 minutes depending which bean I'm cooking.
They always come out great.
If your water isn't even hot something went awry.
Did the lid seal? Have you had problems with any other dishes or just this one?