Darrell said it right. If your old system was smaller, the liquid line may be too small for the new larger system. The installer should have figured that out before he installed the new system. By the way, why did he install a larger unit? Did he do a load calculation? He may have oversized the system. There may be a refrigerant leak in the new system. At any rate, the contractor should come back and take care of the problem.
Stretch