Abstract: A bypass valving fluid control arrangement for a fluid system including a fluid treatment device which permits the removal of the fluid treatment device from the system without interrupting system operation and wherein the bypass valving control comprises a single unitary structure having a single manual control means and valving operation is responsive to pressure conditions within the fluid control arrangement.

Abstract: Actuator means of the pressure- and/or temperature-responsive type are disclosed for controlling valve means which supply pressure fluid (such as a combustible gas) to a load (such as a gas-fired boiler), characterized in that the actuator means are operable (1) when the boiler pressure exceeds a given limit, (2) when the boiler temperature exceeds a given limit, or (3) when the temperature a given region external of the boiler exceeds a given limit. The valve means is normally in an open condition, said actuator means being operable to close the valve means when at least one of the aforementioned limits is exceeded.