A valve for controlling the flow of a liquid coolant in a circuit interconnecting several hollow welding electrodes with a pressurized coolant source has dual ball check valves in the supply and return lines respectively and a spring and pressure responsive device for holding the ball check valve in the supply line open when the fluid pressure of the coolant in the cooling circuit is maintained. The device is responsive in operation to loss of pressure in the coolant supply line and the hollow electrodes to permit the dual ball check valves to close upon a loss of pressure as occasioned by the burn out of one of the electrodes or the removal of the electrode from the circuit. The device may also originate an appropriate signal which may be directed to a remote electrical switch controlling the welding current.