Slow cooker too hot?

[BearPear]

I used to have an old-school Tefal slow cooker (beige plastic surround with brown stoneware dish) which unfortunately got broken. I got a replacement new Tefal and did a tester of fail-safe porridge overnight and was presented with burnt offerings the following morning. I returned the pot as I thought it was faulty and got a branded "Crock Pot" instead.

I'm not sure that this replacement is working properly either - I've had it a couple of years and barely use it because it seems so fierce. There's nothing "slow" about it. As an example, this morning I have pre-heated it on low while I prepped a Mexican beef casserole which took about 20 minutes. When I put my casserole in it was actually spitting on contact it was so hot. I have in the past reduced cooking temperature to the warming setting to slow down the cooking time but this can't be right.

Was I spoilt with my trusty old Tefal and this is what new slow cookers are like?

My old faithful slow cooker broke and I replaced it with a Morphy Richards - it was awful and cooked everything far too quickly.

In the end I went out and bought the same brand that I used to have that I've never had any problems with - Argos Cook Works.

I've had a number over the years, I think my original was the same as yours.

Anyway I find the ones with thinner metal cooking pots to be much hotter than ceramic ones.

I currently have an Argos or possibly Tesco 1/2 size with a ceramic pot and a 6l with metal which cooks more quickly despite smaller quantities I adapt recipes accordingly.

I use my slow cooker (Breville 4.5l) a lot but I never pre-heat it. I do find it quite hot if I use it on high - for example, yesterday I made chocolate brownies in mine and they had caught a little after only 1 3/4 hours.