A.fill the unit with saltwater B.fill the unit with de-scaling compound C.completely drain the unit D.tightly seal the unit to exclude air
A.dischargeendbeingsmallerthanthesuctionend B.smallsizeofimpeller C.lackofmovingparts D.easeatwhichthewearingringsmaybechanged
A.fusion B.vaporization C.sublimation D.condensation