We need some help from the Pro here.

We are installing a 10ton Carrier heat pump split unit system.(R410A) The compressor located on the 8th floor and the fan coil located on the ground floor. Is this require to have liquid solenoid valve?

Also, for the above system the liquid line 1/2 suction line 1 1/8. The install guy use 5/8 for the liquid line and 1 3/8 for the suction. What kind of problem we will face with the over size piping and how can we correct the problem if we can't replace the piping?

Thanks.