Is it safe to use a 20a breaker for a 15a mini split

The question is far too vague.
What is a "15A mini split"?

What do the specs say?
What is the MCA, or minimum circuit ampacity?
What is the maximum breaker rating?

This info should be on the side of the condensing unit.

Min ampacity is 12 and it says max fuse size (time delay) 15.What happened is I ran 12-2 wire because I thought if I ever wanted a larger unit I would not have to run another wire.Then to save room in the panel I wanted 2 single breakers replaced with the breaker that has 2 single 15 on the outside and a double 15 in the middle. I assume the electrician saw the 12-2 wire and thought it was 2 single 15 and a double 20 that I wanted and that is what he installed.Just noticed it and was wondering about it. THX.

If it says max fuse/breaker is 15 you really should change it. If anything for warranty reasons if you ever have a problem. It's a cheap and easy fix.

OK. Thank You.