The lid to this one has a small, circular hole in it which acts as a vent. I seem to recall reading somewhere not to latch the lid down while cooking so more steam can escape, and only use the latches for transporting food. You may have had the temperature too high, and if the crock pot was more than 3/4 full it could overflow or splatter. There are a few variables. Here is where you can find some user manuals: http://www.crock-pot.com/service-%26-support/product-support/instruction-manuals/instruction-manuals.html. Good luck!
The setting on "fast cook" hot does runs a little hot, so instead of 4 hours, I just turn it to "slow cook" around 3.7 hours. Really is nothing major... I have it for awhile now and use it at least once a week. Still love it! Hope this helps.