Funny you should ask. I have been having the same problem myself. I sometimes wonder if the people that make these crock pots ever thought of testing them out with a good chulent. I guess not!
I have made some changes in my use of these crockpots for Chulent purposes.
First of all, make sure you soak your Beans and Barley overnight. That will eliminate some of the starch. The next important thing is to put about an inch of water in the bottom of the crock, prior to lining it. The liner will prevent the water from getting into the chulent and at the same time, forms a barrier between the liner and the chulent That helps a lot. One more thing is to not use the (Automatic switch) which switches over to warm.
Just start off with manually setting your pot to the warm setting from beginning till end. This should help quite a bit.
Worst case scenario is return the product to the company and tell them it is burning your food. Keep trying other brands if the above doesn't work until you find one that's good for you. Most companies will either replace it (perhaps the thermostat is faulty) and send you a new one.
If down the line you find one that's perfect, let me know so I can pass it along to our readers.
One more thing! I occasionally go back to the good old system. Leaving my oven on all Shabbos and baking the chulent at 200 degrees.
Keep me posted.
Note: Linda Kirshstein sent the following note -
I was reading someone's question about how hot the crock pots are. I changed to the wearever versatility slow cooker. Cholent can be started on the stove and moved to the hot plate type unit Friday afternoon. It isn't as hot probably because the pot isn't "enclosed" in the heating unit, it sits on top.