Radiator connector fitting

A fitting for connection between a supply and return of a heat source and an inlet and an outlet of a radiator, the fitting comprising:

• a one-piece body extending along an axis, having two axially opposite ends and two transversely oppositely facing sides, and having on one side a transversely open inlet connector connectable to the heat-source supply and parallel thereto an outlet connector connectable to the heat-source return and on an opposite side a transversely open outlet connector connectable to the radiator inlet and parallel thereto an inlet connector connectable to the radiator outlet, each of the outlet connectors being transversely opposite to a respective one of the inlet connectors, the body being formed with two L-shaped passages each having a transversely extending branch opening at one of the connectors and another axially extending branch opening at one axial end of the body;
• a valve at the one axial end shiftable between a closed position blocking both of the axial branches and an open position unblocking both of the axial passages;
• and
• an accessory releasably connected to the one axial end and communicating with at least one of the axial branches.