possible because of predetermined leakage of water past the piston either around its outer periphery or through one or more small openings provided through the piston until the piston reaches the bottom of the cylinder after a predetermined time interval engaging the end of pin 26a and pushing it downwardly to close the primary inlet valve with the primary inlet valve 26 closed it is not possible for additional water to flow into the tank until a flush cycle is again initiated by operating the flush lever thus even if a leak should develop past the outlet valve 21 resulting in a lowering of the water level in the tank and dropping of the float enabling the inlet valve 13 to open no additional water can flow into the tank since the primary inlet valve 26 remains closed due to contact of the piston 38 with the valve pin 26a a modification of the actuator system for opening the primary inlet valve 26 is shown in fig4 wherein the cable 24 extends to a housing 43 through which the cable wire end 31 extends into close proximity with the abutment 33 on valve pin 26a for direct action on the valve pin rather than acting through an intermediate lever as in the embodiment of fig3 the cable wire 31 is biased away from the abutment 33 by a spring 44 and the end 31 of the cable wire may be encased in a seal 36 such as that used in the embodiment of fig3 in all other respects this form of the invention functions the same as that described in relation to fig3 a modification of the invention of fig2 is indicated generally.