I have a 2 1/2 ton system to change out and upgrade to R-410. The existing liquid line is only 1/4 inch. Suction is 3/4. The A/H is in an attic on a 3rd floor so replacing the lineset is not an option unless ran externally. If the lineset is flushed properly w/ R-11 what problems, if any , will I have with the 1/4 inch liquid line????