17500 gal pool 1hp pump S210T (44 gpm) ....I am hooking up a pool heater (jandy 250K) and the CPVC nipples they give you for entry and exit are 2".....

Skimmer and low suction fitting were going to be piped in 1 1/2" thru pump and filter....can I upsize to 2" for the heater and then make the return (2 returns) 2" or should I stay with 1 1/2" the whole way?

Also....is an equalizer valve a code requirement on the suction side or is just a good idea? Should I take two suction lines both off the skimmer since I have two ports in the skimmer bottom?