A universal valve body includes a front face having a circular opening for receiving a valve cartridge, a rear face, a frustoconical side wall connecting the front face to the rear face, and a first inlet port and a first outlet port obliquely disposed in the frustoconical side wall. A cap for the valve body includes a base and a structure extending from the base. The structure extending from the base may block at least one of the inlet port or outlet port in the valve body. A service valve for a valve body includes a base rotatable between an open orientation and a closed orientation relative to the valve body and a tab extending from the base. When the base is in the open orientation, the tab prevents removal of a cover from the valve body.