RonMJ wrote:I called CC and the correct setting is 0.

The only way to be sure the offset is correct is to measure the brew temperature at the group. Best way to do that is with a Scace. Perhaps you can borrow one.

That said, CC may have measured your machine and recorded the result, or their experience with the machine is that the offset is always zero or very close to it. I'm a little skeptical about that because there's almost always a drop in temperature between the boiler and group.