No parts needed it seems, though let's see if what they did helps. It will take about a day to regulate again - but for now, it is still cold. Smallsteps will stay at grandma's tonight.
It is definitely annoying. We have had lots of issues with it over the last 3.5 years since it was installed and it was meant to be simple and pain-free.
I was going to say, I feel like you have had some other issues with it that you wrote about as well.