I just purchased a hayward heat pump (HP21404t), they recommend on their user guide 2 manual isolation valve (one on the inlet and one on the outlet of the heat pump) also a bypass valve, and a check valve (if you have an automatic chlorinator or salt system, which i do)... My pool builder says that he normally puts the heatpump straight in without any valve not even the check valve.. What is you guys opinion on this? FIY my pump is a 1.85HP