I have had the same concerns for a while now. However, I noticed in the product description that one of the features is "Power-interrupt protection;". It seems like this must not have been the case back when most of the shut-off problems occurred. In any case, I ordered on today.
I bought a replacement lid - or should I say I got a replacement lid, paying only shipping charges ($4.99) - so that I can remove the gasket from the original and check out the seal (or lack thereof). I haven't gotten to that yet, but I noticed right away that the rubber on the replacement lid smells different than the rubber on the original lid. My plan is to try the new lid to see if heat affects the smell. If not, i.e. that the new lid doesn't stink, then the Chinese manufacturer of the cooker is using different rubbers. Hamilton Beach customer service, by the way, has absolutely no customer focus and, by the looks of things, no corrective action in place for this issue despite numerous complaints. It took quite a bit of effort on my part just to have them send me a replacement lid instead of a whole new cooker; and had I let them send me a replacement cooker, they wanted the old one back. I will update this discussion once I have more information.
The cooker has three temperature settings: HIGH, LOW and WARM. It is not specified in the manual what these settings represent in terms of temperature. In addition, the cooker has a probe that you can stick in the food and the cooker can be programmed to switch from HIGH or LOW to WARM when the set temperature is reached. This therefore does not work as a thermostat, but simply as a switch when a certain temperature is reached. The short answer to the question is therefore - I believe - no, you cannot set it to hold a 115 degree temperature.
The lowest temp. would be around 140, as temps. between 41 and 140 are considered the danger zone.
Here is a example of how this pot could work with a yogurt recipe:
Pour 1/2 gallon of milk into the the crock pot. Turn it on to the "high" setting. Cover, and walk away. Let it sit there until it reaches 185 degrees. This pot cooks faster than most pots. so instead of 2 and half hours it would likely be around 1 hour.
When the milk reaches 185 degrees, shift the lid so there is a crack for the heat to escape and turn off the crock pot. Let it cool to 110 degrees.
Add the culture-either 1/2 cup plain yogurt OR 3 tablespoons powdered yogurt culture. Replace the lid, and wrap the whole crock pot in a blanket. (You heard me right, a blanket. Make it a warm one.) Let it sit, undisturbed for 5 to 6 hours. This can also be overnight, if that is where you are in your day.
No, but I don't think you will have a problem. This is the best slow cooker I have had in YEARS since I gave away my old one to my ex-daughter-in-law. Let it cook a long time, it will be fine, use manual on low. I have bought at least 3 large slow-cookers looking for the slow-w-w-w cooking I had before and this is the best I have found. I LOVE this slow cooker.