An apparatus for limiting fluid pressure in a medical catheter retention balloon includes a body that has a fluid inlet port 42 for receiving pressurized fluid and a fluid outlet port 44 connected to the retention balloon. A first passage 40a, 40b, 52, 54 connects the fluid inlet port and the fluid outlet port. A second passage 46a, 46b in the body is connected to the balloon fluid return path 48 and is at the pressure of the retention balloon. A valve 50, 60 prevents fluid flow through the first passage 52 54 when actuated by a pressure-responsive member 60 and is movable to a position to obstruct fluid flow in response to fluid pressure in the second passage exceeding the predetermined level. The ball check valve 56 allows fluid to be withdrawn from the balloon by way of suction applied to inlet port 42.
