I have an old commercial coffee machine and it's been having a problem when it brews. Here's a list of its conditions I observed: 1. Once it's cooled down, it doesn't seem to be able to bring its temp up to its brewing temp, which is 200 degrees. 2. When its whole body is covered with layers of industrial plastic bags and have some heats maintained inside of it, the machine heats up, only when I keep pressing BREW button. 3. With its body covered, the machine takes several hours to heat up to 200 degrees. I replaced its motherboard with a new one last year. So I didn't think the trouble is from it program. Does anyone has any idea what is going on with it?

Coffee Makers & Espresso... - Bunn